Engine Mechanical - 4.3l Chevrolet Chevy Express G3500

Fastener Tightening Specifications

Fastener Tightening Specifications

Engine Mechanical Specifications

Engine Mechanical Specifications

Sealers, Adhesives, and Lubricants

Sealers, Adhesives, and Lubricants

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

1. The Vehicle Identification Number (VIN) Derivative is located on the left side rear of the engine block (1) or on the right side rear (2) and typically is a 9 digit number stamped or laser etched onto the engine at the vehicle assembly plant. The first digit identifies the division. The second digit identifies the model year. The third digit identifies the assembly plant. The fourth through ninth digits are the last six digits of the VIN.
2. Engines built at the Romulus engine plant have the engine identification number located at the right front top of the engine block. The first digit (1) is the source code. The second and third digits (2) are the month of build. The fourth digit (3) is the hour of the build. The fifth and sixth digits (4) are the date of build. The seventh, eighth, and ninth digits (5) are the broadcast code.

Diagnostic Starting Point - Engine Mechanical

Begin the system diagnosis by reviewing the Disassembled Views , Engine Component Description , Lubrication Description , New Product Information and the Drive Belt System Description . Reviewing the description and operation information will help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing the description and operation information will also help you determine if the condition described by the customer is normal operation. Refer to Symptoms - Engine Mechanical in order to identify the correct procedure for diagnosing the system and where the procedure is located.

Strategy Based Diagnostics

1. Perform the «Diagnostic System Check - Engine Controls»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-diagnostic-information-procedures) in Engine Controls before using the symptom tables, if applicable.
2. Review the system operations in order to familiarize yourself with the system functions. Refer to «Disassembled Views»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) , «Engine Component Description»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) , «Lubrication Description»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__lubrication-description) , and «New Product Information»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__new-product-information) in Engine Unit Repair Manual and to «Drive Belt System Description»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__drive-belt-system-description) .

All diagnosis on a vehicle should follow a logical process. Strategy based diagnostics is a uniform approach for repairing all systems. The diagnostic flow may always be used in order to resolve a system problem. The diagnostic flow is the place to start when repairs are necessary. For a detailed explanation, refer to Strategy Based Diagnosis in General Information.

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Engine. Refer to «Checking Aftermarket Accessories»(/chevrolet/chevy-express-g3500/1996-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__checking-aftermarket-accessories) in Wiring Systems.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Check for the correct oil level, proper oil viscosity, and correct filter application.
4. Verify the exact operating conditions under which the concern exists. Note factors such as engine RPM, ambient temperature, engine temperature, amount of engine warm-up time, and other specifics.
5. Compare the engine sounds, if applicable, to a known good engine and make sure you are not trying to correct a normal condition.

Intermittent

Test the vehicle under the same conditions that the customer reported in order to verify the system is operating properly.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Base Engine Misfire without Internal Engine Noises»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__base-engine-misfire-without-internal-engine)
2. «Base Engine Misfire with Abnormal Internal Lower Engine Noises»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__base-engine-misfire-with-abnormal-internal)
3. «Base Engine Misfire with Abnormal Valve Train Noise»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__base-engine-misfire-with-abnormal-valve)
4. «Base Engine Misfire with Coolant Consumption»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__base-engine-misfire-with-coolant-consumption)
5. «Base Engine Misfire with Excessive Oil Consumption»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__base-engine-misfire-with-excessive-oil)
6. «Engine Compression Test»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-compression-test)
7. «Engine Noise on Start-Up, but Only Lasting a Few Seconds»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-noise-on-start-up-but-only)
8. «Upper Engine Noise, Regardless of Engine Speed»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__upper-engine-noise-regardless-of-engine)
9. «Lower Engine Noise, Regardless of Engine Speed»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__lower-engine-noise-regardless-of-engine)
10. «Engine Noise Under Load»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-noise-under-load)
11. «Engine Will Not Crank - Crankshaft Will Not Rotate»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-will-not-crank-crankshaft)
12. «Oil Consumption Diagnosis»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__oil-consumption-diagnosis)
13. «Oil Pressure Diagnosis and Testing»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__oil-pressure-diagnosis-and-testing)
14. «Oil Leak Diagnosis»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__oil-leak-diagnosis)

Base Engine Misfire without Internal Engine Noises

Base Engine Misfire Without Internal Engine Noises

Base Engine Misfire with Abnormal Internal Lower Engine Noises

Base Engine Misfire With Abnormal Internal Lower Engine Noises

Base Engine Misfire with Abnormal Valve Train Noise

Base Engine Misfire With Abnormal Valve Train Noise

Base Engine Misfire with Coolant Consumption

Base Engine Misfire With Coolant Consumption

Base Engine Misfire with Excessive Oil Consumption

Base Engine Misfire With Excessive Oil Consumption

Engine Noise on Start-Up, but Only Lasting a Few Seconds

Engine Noise On Start-Up, But Only Lasting A Few Seconds

Upper Engine Noise, Regardless of Engine Speed

Upper Engine Noise, Regardless Of Engine Speed

Lower Engine Noise, Regardless of Engine Speed

Lower Engine Noise, Regardless Of Engine Speed

Engine Noise Under Load

Engine Noise Under Load

Engine Will Not Crank - Crankshaft Will Not Rotate

Engine Will Not Crank - Crankshaft Will Not Rotate

Coolant in Combustion Chamber

Coolant In Combustion Chamber

Coolant in Engine Oil

Coolant In Engine Oil

Engine Compression Test

1. Ensure that the vehicle batteries are in good condition, and fully charged.
2. Operate the vehicle until the engine is at normal operating temperature.
3. Disconnect the positive ignition coil wire plug from the ignition coil.
4. Disconnect the fuel injector electrical connector.
5. Remove all of the spark plugs.
6. Block the throttle linkage wide open.
7. Install the engine cylinder compression gage to the cylinder being tested.
8. Using the vehicle starter motor, rotate, or crank the engine for 4 compression strokes, or puffs, for the cylinder being tested. If the engine rotates for more than 4 compression strokes, test the cylinder again.
9. Record the compression reading.
10. Remove the engine cylinder compression gage from the cylinder being tested.
11. Repeat steps 8-11 for each additional cylinder. All cylinders must be tested to obtain valid test results.
12. If any cylinders have low compression, inject approximately 15 ml (1 oz) of engine oil into the cylinder through the spark plug hole.
13. Repeat steps 8-11 for all low compression cylinders.
14. The minimum compression in any one cylinder should not be less than 70 percent of the highest cylinder. No cylinder should read less than 690 kpa (100 psi). For example, if the highest pressure in any one cylinder is 1035 kPa (150 psi), the lowest allowable pressure for any other cylinder would be 725 kPa (105 psi). Multiply the highest cylinder pressure by 70 percent, 1035 kPa x 70 percent = 725 kPa (150 psi x 70 percent = 105 psi), in order to determine the lowest allowable pressure in any other cylinder. Normal The compression builds up quickly and evenly to the specified compression. Piston rings leaking Compression is low on the first compression stroke. The compression builds up on the following strokes, but does not reach normal. Compression improves considerably when you add oil. Valves leaking Compression is low on the first compression stroke. The compression does not build up on the following strokes, and does not reach normal. Compression does not improve much, if at all, when you add oil. Head gasket leaking Compression is low on the first stroke. The compression does not build up on the following strokes, and does not reach normal. Compression does not improve much, if at all, when you add oil. Adjacent cylinders have the same, or similar, low compression readings.
15. If one or more cylinders fails to meet the minimum specified compression, repair or replace all damaged or worn components and test the engine again.

Cylinder Leakage Test

Tools Required: J 35667-A Cylinder Head Leakdown Tester. See Special Tools and Equipment .

With the use of air pressure, a cylinder leakage test will aid in the diagnosis. Use the cylinder leakage test in conjunction with the engine compression test in order to isolate the cause of leaking cylinders.

1. Disconnect the battery ground negative cable.
2. Remove the spark plugs. Refer to «Spark Plug Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
3. Rotate the crankshaft to place the piston in the cylinder being tested at top dead center (TDC) of the compression stroke, with both valves closed.
4. Install the J 35667-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Apply shop air pressure to the J 35667-A and adjust according to the manufacturer instructions. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
6. Record the cylinder leakage value. Cylinder leakage that exceeds 25 percent is considered excessive and may require component service. In excessive leakage situations, inspect for the following conditions: Air leakage from the intake or exhaust system may indicate a worn or burnt valve or a broken valve spring. Remove the valve rocker arm cover of the suspect cylinder head. Refer to «Valve Rocker Arm Cover Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Valve Rocker Arm Cover Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Ensure that both valves are closed. Inspect the cylinder head for a broken valve spring. Remove and inspect the suspect cylinder head. Refer to «Cylinder Head Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Cylinder Head Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Air leakage from the crankcase, oil level indicator, or oil fill tube may indicate worn piston rings, a damaged piston, a worn or scored cylinder bore, a damaged engine block or a damaged cylinder head. Remove the piston from the suspect cylinder. Refer to «Piston, Connecting Rod, and Bearing Removal»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__piston-connecting-rod-and-bearing-removal) or «Piston, Connecting Rod, and Bearing Installation»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__piston-connecting-rod-and-bearing-installation) . Inspect the piston and connecting rod assembly. Refer to «Piston, Connecting Rod, and Bearings Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Inspect the engine block. Refer to «Engine Block Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-block-cleaning-and-inspection) . Inspect the cylinder head. Refer to «Cylinder Head Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__cylinder-head-cleaning-and-inspection) . Air bubbles in the cooling system may indicate a damaged cylinder head or a damaged cylinder head gasket. Remove both cylinder heads. Refer to «Cylinder Head Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Cylinder Head Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Inspect both cylinder heads. Refer to «Cylinder Head Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__cylinder-head-cleaning-and-inspection) . Inspect the engine block. Refer to «Engine Block Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-block-cleaning-and-inspection) .
7. Remove the J 35667-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
8. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 4.3L.
9. Connect the battery ground negative cable.

Oil Consumption Diagnosis

Excessive oil consumption, not due to leaks, is the use of 1 liter (1 quart) of engine oil within 3 200 kilometers (2,000 miles). However, during initial engine break-in periods 4 828-6 437 kilometers (3,000-4,000 miles), oil consumption may exceed 1 liter (1 quart) or more. The causes of excessive oil consumption include the following conditions

1. External oil leaks Tighten the bolts and/or replace gaskets and oil seals as necessary.
2. Incorrect oil level or improper reading of oil level indicator With the vehicle on a level surface, allow adequate drain down time and check for the correct oil level.
3. Improper oil viscosity Use recommended SAE viscosity for the prevailing temperatures.
4. Continuous high speed driving and/or severe usage
5. Crankcase ventilation system restrictions or malfunctioning components
6. Valve guides and/or valve stem oil seals worn, damaged, or the seal omitted Ream the valve guides and install oversize service valves and/or new valve stem oil seals.
7. Piston rings broken, improperly installed, worn, or not seated properly Allow adequate time for the piston rings to seat. Replace broken or worn piston rings as necessary.
8. Piston improperly installed or miss-fitted

Oil Pressure Diagnosis and Testing

1. With the vehicle on a level surface, allow adequate drain down time, 2-3 minutes, and measure for a low engine oil level. Add the recommended grade engine oil, and fill the crankcase until the oil level measures FULL on the oil level indicator.
2. Operate the engine and verify low or no oil pressure on the vehicle oil pressure gage or the oil indicator light. Listen for a noisy valve train or a knocking noise.
3. Inspect for the following: Engine oil diluted by moisture or unburned fuel mixtures Improper engine oil viscosity for the expected temperature Incorrect or faulty oil pressure gage sensor Incorrect or faulty oil pressure gage Plugged oil filter Malfunctioning oil filter bypass valve
4. Remove the oil pressure gage sensor or another engine block oil gallery plug.
5. Install an oil pressure gage.
6. Start the engine and then allow the engine to reach normal operation temperature.
7. Measure the engine oil pressure at the following RPM: Specification: 42 kPa (6 psig) minimum, at 1,000 RPM 125 kPa (18 psig) minimum, at 2,000 RPM 166 kPa (24 psig) minimum, at 4,000 RPM
8. If the engine oil pressure is below minimum specifications, inspect the engine for one or more of the following: Oil pump worn or dirty Malfunctioning oil pump pressure relief valve Oil pump screen loose, plugged, or damaged Excessive bearing clearance Cracked, porous or restricted oil galleries Engine block oil gallery plugs missing or incorrectly installed Broken valve lifters

Oil Leak Diagnosis

Oil Leak Diagnosis

Results Of Incorrect Operation

1. A plugged valve or hose may cause the following conditions: Rough idle Stalling or slow idle speed Oil leaks Oil in air cleaner Sludge in engine
2. A leaking crankcase ventilation valve or hose may cause the following conditions: Rough idle Stalling High idle speed

Functional Check

With these systems, any blow-by in excess of the system capacity, from a badly worn engine, sustained heavy load, etc., is exhausted into the air cleaner and is drawn into the engine.

Proper operation of the crankcase ventilation system depends upon a sealed engine. If oil slugging or dilution is noted and the crankcase ventilation system is functioning properly, check the engine for a possible cause. Correct any problems.

If an engine is idling rough, check for a clogged crankcase ventilation valve, a dirty vent filter, air cleaner element, or plugged hose. Replace as required. Use the following procedure

1. Remove the crankcase ventilation valve from the rocker arm cover.
2. Operate the engine at idle.
3. Place your thumb over the end of the valve in order to check for a vacuum. If there is no vacuum at the valve, check for the following items: Plugged hoses The manifold port The crankcase ventilation valve
4. Turn OFF the engine. Remove the crankcase ventilation valve. Shake the valve. Listen for the rattle of the check needle inside of the valve. If valve does not rattle, replace the valve.

Diagnostic Aids

The symptom may be intermittent due to moisture on the drive belts or the pulleys. It may be necessary to spray a small amount of water on the drive belts in order to duplicate the customers concern. If spraying water on the drive belts duplicates the symptom, cleaning the belt pulleys may be the probable solution.

A loose or improper installation of a body component, a suspension component, or other items of the vehicle may cause the chirping noise.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 2: The noise may not be engine related. This step is to verify that the engine is making the noise. If the engine is not making the noise do not proceed further with this table.
2. 3: The noise may be an internal engine noise. Removing the drive belt and operating the engine for a brief period will verify the noise is related to the drive belt. When removing the drive belts the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belt removed.
3. 4: Inspect all drive belt pulleys for pilling. Pilling is the small balls or pills or it can be strings in the drive belt grooves from the accumulation of rubber dust.
4. 6: Misalignment of the pulleys may be caused from improper mounting of the accessory drive component, incorrect installation of the accessory drive component pulley, or the pulley bent inward or outward from a previous repair. Test for a misalign pulley using a straight edge in the pulley grooves across two or three pulleys. If a misalign pulley is found refer to that accessory drive component for the proper installation procedure for that pulley.
5. 10: Inspecting of the fasteners can eliminate the possibility that a wrong bolt, nut, spacer, or washer was installed.
6. 12: Inspecting the pulleys for being bent should include inspecting for a dent or other damage to the pulleys that would prevent the drive belt from not seating properly in all of the pulley grooves or on the smooth surface of a pulley when the back side of the belt is used to drive the pulley.
7. 14: Replacing the drive belt when it is not damaged or there is not excessive pilling will only be a temporary repair.

Drive Belt Chirping Diagnosis

A loose or improper installation of a body component, a suspension component, or other items of the vehicle may cause the squeal noise.

If the noise is intermittent, verify the accessory drive components by varying their loads making sure they are operated to their maximum capacity. An overcharged A/C system, power steering system with a pinched hose or wrong fluid, or a generator failing are suggested items to inspect.

The numbers below refer to the step numbers on the diagnostic table.

1. 2: The noise may not be engine related. This step is to verify that the engine is making the noise. If the engine is not making the noise do not proceed further with this table.
2. 3: The noise may be an internal engine noise. Removing the drive belt and operating the engine for a brief period will verify the squeal noise is the drive belts or an accessory drive component. When removing the drive belt the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belt removed.
3. 4: This test is to verify that an accessory drive component does not have a seized bearing. With the belt remove test the bearings in the accessory drive components for turning smoothly. Also test the accessory drive components with the engine operating by varying the load on the components to verify that the components operate properly.
4. 5: This test is to verify that the drive belt tensioner operates properly. If the drive belt tensioner is not operating properly, proper belt tension may not be achieved to keep the drive belt from slipping which could cause a squeal noise.
5. 6: This test is to verify that the drive belt(s) is not too long, which would prevent the drive belt tensioner from working properly. Also if an incorrect length drive belt was installed, it may not be routed properly and may be turning an accessory drive component in the wrong direction.
6. 7: Misalignment of the pulleys may be caused from improper mounting of the accessory drive component, incorrect installation of the accessory drive component pulley, or the pulley bent inward or outward from a previous repair. Test for a misalign pulley using a straight edge in the pulley grooves across two or three pulleys. If a misalign pulley is found refer to that accessory drive component for the proper installation procedure for that pulley.
7. 8: This test is to verify that the pulleys are the correct diameter or width. Using a known good vehicle compare the pulley sizes.

Drive Belt Squeal Diagnosis

The drive belts will not cause the whine noise.

If the whine noise is intermittent, verify the accessory drive components by varying their loads making sure they are operated to their maximum capacity. Such items but not limited to may be an A/C system overcharged, the power steering system restricted or the wrong fluid, or the generator failing.

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This test is to verify that the noise is being caused by the drive belt(s) or the accessory drive components. When removing the drive belt the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belt removed.
2. 4: The inspection should include checking the drive belt tensioner and the drive belt idler pulley bearings. The drive belts may have to be installed and the accessory drive components operated separately by varying their loads. Refer to the suspected accessory drive component for the proper inspection and replacement procedure.

Drive Belt Whine Diagnosis

Vibration from the engine operating may cause a body component or another part of the vehicle to make rumbling noise.

The drive belts may have a condition that can not be seen or felt. Sometimes replacing the drive belt may be the only repair for the symptom.

If replacing the drive belts, completing the diagnostic table, and the noise is only heard when the drive belts is installed, there might be an accessory drive component with a failure. Varying the load on the different accessory drive components may aid in identifying which component is causing the rumbling noise.

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This test is to verify that the symptom is present during diagnosing. Other vehicle components may cause a similar symptom.
2. 3: This test is to verify that the drive belts is causing the rumbling noise. Rumbling noise may be confused with an internal engine noise due to the similarity in the description. Remove only one drive belt at a time if the vehicle has multiple drive belts. When removing the drive belt the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belt removed.
3. 4: Inspecting the drive belts is to ensure that it is not causing a the noise. Small cracks across the ribs of the drive belt will not cause the noise. Belt separation is identified by the plys of the belt separating and may be seen at the edge of the belt our felt as a lump in the belt.
4. 5: Small amounts of pilling is normal condition and acceptable. When the pilling is severe the drive belt does not have a smooth surface for proper operation.

Drive Belt Rumbling Diagnosis

The accessory drive components can have an affect on engine vibration. Such as but not limited to the A/C system over charged, the power steering system restricted or the incorrect fluid, or an extra load on the generator. To help identify an intermittent or an improper condition, vary the loads on the accessory drive components.

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This test is to verify that the symptom is present during diagnosing. Other vehicle components may cause a similar symptom such as the exhaust system, or the drivetrain.
2. 3: This test is to verify that the drive belts or accessory drive components may be causing the vibration. When removing the drive belt the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belt removed.
3. 4: The drive belts may cause a vibration. While the drive belts is removed this is the best time to inspect the condition of the belt.
4. 6: Inspecting of the fasteners can eliminate the possibility that a wrong bolt, nut, spacer, or washer was installed.
5. 8: This step should only be performed if the fan is driven by the drive belt. Inspect the engine cooling fan for bent, twisted, loose, or cracked blades. Inspect the fan clutch for smoothness, ease of turning. Inspect for a bent fan shaft or bent mounting flange.
6. 9: This step should only be performed if the water pump is driven by the drive belt. Inspect the water pump shaft for being bent. Also inspect the water pump bearings for smoothness and excessive play. Compare the water pump with a known good water pump.
7. 10: Accessory drive component brackets that are bent, cracked, or loose may put extra strain on that accessory component causing it to vibrate.

Drive Belt Vibration Diagnosis

If the drive belts repeatedly falls off the drive belt pulleys, this is because of pulley misalignment.

An extra load that is quickly applied on released by an accessory drive component may cause the drive belt to fall off the pulleys. Verify the accessory drive components operate properly.

If the drive belt(s) is the incorrect length, the drive belt tensioner may not keep the proper tension on the drive belt.

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This inspection is to verify the condition of the drive belt. Damage may of occurred to the drive belt when the drive belt fell off. The drive belt may of been damaged, which caused the drive belt to fall off. Inspect the belt for cuts, tears, sections of ribs missing, or damaged belt plys.
2. 4: Misalignment of the pulleys may be caused from improper mounting of the accessory drive component, incorrect installation of the accessory drive component pulley, or the pulley bent inward or outward from a previous repair. Test for a misaligned pulley using a straight edge in the pulley grooves across two or three pulleys. If a misaligned pulley is found refer to that accessory drive component for the proper installation procedure of that pulley.
3. 5: Inspecting the pulleys for being bent should include inspecting for a dent or other damage to the pulleys that would prevent the drive belt from not seating properly in all of the pulley grooves or on the smooth surface of a pulley when the back side of the belt is used to drive the pulley.
4. 6: Accessory drive component brackets that are bent or cracked will let the drive belt fall off.
5. 7: Inspecting of the fasteners can eliminate the possibility that a wrong bolt, nut, spacer, or washer was installed. Missing. loose, or the wrong fasteners may cause pulley misalignment from the bracket moving under load. Over tightening of the fasteners may cause misalignment of the accessory component bracket.

Drive Belt Falls Off Diagnosis

Excessive wear on a drive belts is usually caused by an incorrect installation or the wrong drive belt for the application.

Minor misalignment of the drive belt pulleys will not cause excessive wear, but will probably cause the drive belts to make a noise or to fall off.

Excessive misalignment of the drive belt pulleys will cause excessive wear but may also make the drive belts fall off.

The numbers below refer to the step numbers on the diagnostic table.

1. 2: The inspection is to verify the drive belts is correctly installed on all of the drive belt pulleys. Wear on the drive belts may be caused by mis-positioning the drive belts by one groove on a pulley.
2. 3: The installation of a drive belt that is two wide or two narrow will cause wear on the drive belt. The drive belt ribs should match all of the grooves on all of the pulleys.
3. 4: This inspection is to verify the drive belts is not contacting any parts of the engine or body while the engine is operating. There should be sufficient clearance when the drive belt accessory drive components load varies. The drive belts should not come in contact with an engine or a body component when snapping the throttle.

Drive Belt Excessive Wear Diagnosis

Inspection Procedure

1. Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Position a 3/8 inch drive wrench on the drive belt tensioner arm and rotate the arm counterclockwise.
3. Move the drive belt tensioner through it's full travel. The movement should feel smooth. There should be no binding. The tensioner should return freely.
4. If any binding is observed, replace the drive belt tensioner. Refer to «Drive Belt Tensioner Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Removal Procedure

1. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
2. Remove the retaining bolt for the coolant recovery reservoir and set the reservoir aside.
3. Install a 3/8 inch drive wrench on the drive belt tensioner arm and rotate the arm counterclockwise.
4. Remove the drive belt.
5. Slowly release the tension on the drive belt tensioner arm.

Installation Procedure

1. Route the drive belt over all the pulleys except the drive belt tensioner arm.
2. Observe the drive belt routing for vehicles without air conditioning.
3. Observe the drive belt routing for vehicles with air conditioning.
4. Install a 3/8 inch drive wrench on the drive belt tensioner arm and rotate the arm counterclockwise.
5. Install the drive belt over the drive belt tensioner pulley.
6. Slowly release the tension on the drive belt tensioner arm.
7. Confirm that the belt is properly routed.
8. Inspect for the drive belt being properly installed on the pulleys.
9. Avoid mis-positioning the drive belt by one or more grooves.
10. Confirm for the proper drive belt size and the correct drive belt routing by observing the location of the fix pointer and the index marks on the drive belt tensioner. With a new drive belt installed, the fix pointer should align within the indentation on the drive belt tensioner.
11. With a used drive belt installed, the fix pointer should not align past the index mark.
12. Position the coolant recovery reservoir and install the retaining bolt. Tighten: Tighten the coolant recovery reservoir bolt to 11 N.m (97 lb in).
13. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.

1. Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the bolt.
3. Remove the drive belt tensioner.

1. Install the drive belt tensioner assembly.
2. Install the attaching bolt. Tighten: Tighten the tensioner assembly bolt to 50 N.m (37 lb ft).
3. Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Remove the upper fan shroud. Refer to «Fan Shroud Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
2. Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Remove the belt idler pulley bolt.
4. Remove the belt idler pulley from the power steering pump mounting bracket.

1. Install the belt idler pulley and bolt to the power steering pump mounting bracket. Tighten: Tighten the idler pulley bolt to 50 N.m (37 lb ft).
2. Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Install the upper fan shroud. Refer to «Fan Shroud Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.

Engine Mount Inspection

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Inspect for loose or missing bolts at the following locations: The engine mount bracket to the engine. The engine mount to the frame.
3. Replace loose or missing bolts. Refer to the following procedures: «Engine Mount Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) «Engine Mount Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l)
4. Remove the starter, when checking the right side only. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
5. Using a jack on the square tab at the rear of the engine block raise the engine in order to complete the following tasks: Remove weight from the engine mount. Place a slight tension on the rubber cushion. Observe the engine mount while raising the engine.
6. Replace the engine mount if the following conditions exist: Heat check cracks cover the hard rubber surface. The rubber cushion is separated from the metal plate of the engine mount. There is a split through the rubber cushion.
7. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the engine mount to frame mounting bolts.
3. Use a jack on the square tab at the rear of the engine block, and raise the engine, left side shown.
4. Remove the engine mount to engine mounting bolts.
5. Remove the engine mount.

1. Install the engine mount to the vehicle.
2. Install the engine mount to engine mounting bolts. Tighten: Tighten the engine mount to engine bolts to 50 N.m (37 lb ft).
3. Lower the engine.
4. Install the engine mount to frame mounting bolts. Tighten: Tighten the engine mount to frame bolts to 60 N.m (44 lb ft).
5. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the starter. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
3. Remove the engine mount to frame mounting bolts.
4. Use a jack on the square tab at the rear of the engine block, and raise the engine, left side shown.
5. Remove the engine mount to engine mounting bolts.
6. Remove the engine mount from the vehicle.

1. Install the engine mount to the vehicle.
2. Install the engine mount to engine mounting bolts. Tighten: Tighten the engine mount to engine mounting bolts to 50 N.m (37 lb ft).
3. Lower the engine.
4. Install the engine mount to the frame mounting bolts. Tighten: Tighten the engine mount to frame mounting bolts to 60 N.m (44 lb ft).
5. Install the starter. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
6. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the engine mount. Refer to «Engine Mount Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Engine Mount Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Remove the engine mount adapter mounting bolts.
4. Remove the engine mount adapter.

1. Install the engine mount adapter.
2. Install the engine mount adapter mounting bolts. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
3. Install the engine mount. Refer to «Engine Mount Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Engine Mount Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Lower the vehicle.

1. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
2. Disconnect the PCV valve hose assembly from the intake manifold.
3. Disconnect the PCV valve hose assembly from the left valve rocker arm cover.
4. Inspect the tube and hose for cuts or cracking.
5. Inspect the grommets in the valve rocker arm covers for cuts or cracking.
6. Replace the PCV hose/tube as required.

1. Connect the PCV valve hose assembly to the intake manifold.
2. Connect the PCV valve hose assembly to the left valve rocker arm cover.
3. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.

1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Disconnect the positive crankcase ventilation (PCV) tube from the air cleaner duct.
3. Disconnect the PCV tube from the right valve rocker arm cover.
4. Disconnect the PCV valve hose assembly from the intake manifold.
5. Disconnect the PCV valve hose assembly from the left valve rocker arm cover.
6. Inspect the tube and hose for cuts or cracking.
7. Inspect the grommets in the valve rocker arm covers for cuts or cracking.
8. Replace the PCV hose/tube as required.

1. Connect the PCV valve hose assembly to the intake manifold.
2. Connect the PCV valve hose assembly to the left valve rocker arm cover.
3. Connect the positive crankcase PCV tube to the air cleaner duct.
4. Connect the PCV tube to the right valve rocker arm cover.
5. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
3. Remove the coolant reservoir bolt and set the reservoir aside.
4. Disconnect the positive crankcase ventilation (PCV) tube from the air cleaner outlet duct.
5. Remove the retaining nut (1) from the air cleaner outlet.
6. Remove the air cleaner outlet duct (2) from the throttle body assembly.
7. Disconnect the accelerator control cable from the throttle shaft and the accelerator control cable bracket. Refer to «Accelerator Controls Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
8. Disconnect the cruise control cable, if equipped, from the throttle shaft and the accelerator control cable bracket. Refer to «Cruise Control Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cruise-control-systems/#cruise-control-system) in Cruise Control.
9. Remove the PCV valve hose assembly from the intake manifold and the valve rocker arm cover.
10. Disconnect the following electrical connectors: The fuel meter body assembly connector (1) The EVAP canister purge solenoid valve (2) The manifold absolute pressure (MAP) sensor (3)
11. Disconnect the following electrical connectors: The throttle position (TP) sensor (1) The idle air control (IAC) motor (2) The engine coolant temperature (ECT) gage sensor (3) The A/C high pressure switch (4), if equipped
12. Remove the engine wiring harness bracket from the intake manifold stud.
13. Move and secure the engine wiring harness out of the way.
14. Disconnect the A/C vacuum hose from the intake manifold.
15. Remove the power brake booster vacuum hose bracket and nut from the intake manifold stud.
16. Disconnect the power brake booster vacuum hose from the intake manifold.
17. Remove the accelerator control cable bracket from the throttle body and the intake manifold.
18. Remove the EVAP canister purge solenoid valve. Refer to «Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
19. Remove the fuel lines from the fuel meter body assembly. Refer to «Fuel Hose/Pipes Replacement - Engine Compartment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
20. Remove the distributor cap. Refer to «Distributor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Electrical.
21. Remove the ignition control module. Refer to «Ignition Control Module Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Electrical.
22. Remove the studs for the upper intake manifold.
23. Remove the upper intake manifold.
24. Remove the upper intake manifold gasket from the groove.
25. Discard the gasket.
26. Remove the seal from the fuel meter body assembly.
27. Discard the seal.
28. Clean all sealing surfaces and the inside of the upper intake manifold with a shop towel and cleaning solvent.
29. Inspect the upper intake manifold for the following: Cracks or other damage to the exterior Cracking or damage to the gasket grooves Loose or damaged bolt hole thread inserts
30. If replacing the upper intake manifold, turn and remove the power brake booster vacuum tube fitting from the upper intake manifold.
31. Remove and discard the seal.
32. If replacing the upper intake manifold, turn and remove the PCV valve cover from the upper intake manifold.
33. Remove and discard the seal.
34. Remove the throttle body if replacing the upper intake manifold. Refer to «Throttle Body Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
35. Remove the MAP sensor if replacing the upper intake manifold. Refer to «Manifold Absolute Pressure (MAP) Sensor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.

Scheme 8

Scheme 9

Scheme 10

Scheme 11

1. Install the throttle body, if removed. Refer to «Throttle Body Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) .
2. Install the MAP sensor, if removed. Refer to «Manifold Absolute Pressure (MAP) Sensor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
3. Install the PCV valve cover, if removed, using the following procedure: Install a NEW seal (O-ring) on the PCV valve cover. Lubricate the seal with clean engine oil. Install the PCV valve cover in the upper intake manifold. Turn and lock the PCV valve cover in position.
4. Install the power brake booster vacuum tube fitting, if removed, using the following procedure: Install a NEW seal (O-ring) on the power brake booster vacuum tube fitting. Lubricate the seal with clean engine oil. Install the power brake booster vacuum tube fitting in the upper intake manifold. Turn and lock the power brake booster vacuum tube fitting in position.
5. Install a NEW seal on the fuel meter body assembly.
6. Lubricate the seal with clean engine oil.
7. Install a NEW upper intake manifold to lower intake manifold gasket in the groove of the upper intake manifold.
8. Install the upper intake manifold onto the lower intake manifold.
9. If reusing the fasteners, apply Threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the upper intake manifold attaching bolts.
10. Install the upper intake manifold attaching studs. Tighten: Tighten the upper intake manifold attaching studs on the first pass to 5 N.m (44 lb in). Tighten the upper intake manifold attaching studs on the final pass to 9 N.m (80 lb in).
11. Install the fuel lines to the fuel meter body assembly. Refer to «Fuel Hose/Pipes Replacement - Engine Compartment»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
12. Install the distributor cap. Refer to «Distributor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Electrical.
13. Install the ignition control module. Refer to «Ignition Control Module Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Electrical.
14. Install the EVAP canister purge solenoid valve. Refer to «Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
15. Install the accelerator control cable bracket, studs, and nuts to the intake manifold and the throttle body. Tighten: Tighten the accelerator control cable bracket nuts and studs to 12 N.m (106 lb in).
16. Connect the A/C vacuum hose to the intake manifold.
17. Install the power brake booster vacuum hose bracket and nut to the intake manifold stud. Tighten: Tighten the power brake booster vacuum hose bracket nut to 11 N.m (97 lb in).
18. Connect the power brake booster vacuum hose to the intake manifold.
19. Install the bracket for the engine wiring harness on the lower intake manifold stud.
20. Install the engine wiring harness bracket nut. Tighten: Tighten the engine wiring harness bracket nut to 12 N.m (106 lb in).
21. Connect the following electrical connectors: The fuel meter body assembly connector (1) The EVAP canister purge solenoid valve (2) The manifold absolute pressure (MAP) sensor (3)
22. Connect the following electrical connectors: The throttle position (TP) sensor (1) The idle air control (IAC) motor (2) The engine coolant temperature (ECT) gage sensor (3) The A/C high pressure switch (4), if equipped
23. Connect the PCV valve hose assembly to the intake manifold and the valve rocker arm cover.
24. Install the cruise control cable, if equipped to the throttle shaft and the accelerator control cable bracket. Refer to «Cruise Control Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cruise-control-systems/#cruise-control-system) in Cruise Control.
25. Install the accelerator control cable to the throttle shaft and the accelerator control cable bracket. Refer to «Accelerator Controls Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
26. Install the air cleaner outlet duct (2) on the throttle body assembly.
27. Tighten the retaining nut (1). Tighten: Tighten the nut to 2 N.m (18 lb in).
28. Connect the PCV tube to the air cleaner outlet duct.
29. Position the coolant reservoir. Install the bolt. Tighten: Tighten the bolt to 11 N.m (97 lb in).
30. Install the air cleaner. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
31. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

Scheme 12

1. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Drain the cooling system. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Remove the upper intake. Refer to «Intake Manifold Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Disconnect the A/C compressor (1) and the exhaust gas recirculation (EGR) connector (2).
5. Remove the ground wire (4) from the stud at the water outlet.
6. Remove the radiator inlet hose at the water outlet. Refer to «Radiator Hose Replacement - Inlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
7. Remove the heater hose from the intake manifold. Refer to «Heater Hose Replacement - Inlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) and «Heater Hose Replacement - Outlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
8. Remove the water pump inlet hose from the intake manifold.
9. Remove the accelerator control cable bracket from the throttle body and the intake manifold.
10. Remove the distributor. Refer to «Distributor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
11. Remove the spark plug wire harness retainer from the EGR valve inlet pipe.
12. In order to remove the front intake manifold bolt, perform the following: Remove the A/C compressor discharge hose from the vehicle. Refer to «Discharge Hose Replacement (4.8L, 5.3L, 6.0L )»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Discharge Hose Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning. Remove the A/C compressor suction hose from the vehicle. Refer to «Suction Hose Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning. Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Loosen the nut for the power steering pump rear bracket. Remove the bolts and the nut for the power steering pump mounting bracket. Leave the A/C compressor, if equipped, and the power steering pump on the bracket. Slide the power steering pump bracket forward to access the bolt at the front of the intake manifold.
13. Remove the engine coolant temperature (ECT) sensor wire connector, if equipped, from the engine wiring harness bracket.
14. Remove the lower intake manifold bolts.
15. Remove the intake manifold assembly.
16. Remove and discard the lower intake manifold gaskets.
17. Clean all sealing surfaces and the intake manifold. Refer to «Intake Manifold Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
18. If the intake manifold requires replacement refer to «Intake Manifold Disassemble (LU3)»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__intake-manifold-disassemble-lu3) and «Intake Manifold Assemble (LU3)»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Scheme 13

1. Apply a 4.0 mm (0.157 in) patch of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent to the cylinder head side of the lower intake manifold gasket at each end.
2. Install the lower intake manifold gasket onto the cylinder head. Use the gasket locator pins in order to properly seat the lower intake manifold gasket on the cylinder head.
3. Apply a 5 mm (0.197 in) bead of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent to the front top of the engine block.
4. Extend the adhesive bead 13 mm (0.50 in) onto each lower intake manifold gasket.
5. Apply a 5 mm (0.197 in) bead of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent to the rear top of the engine block.
6. Extend the adhesive bead 13 mm (0.50 in) onto each lower intake manifold gasket.
7. Install the lower intake manifold onto the engine block.
8. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the lower intake manifold bolts.
9. Install the lower intake manifold bolts.
10. Tighten the lower intake manifold bolts. Tighten: Tighten the bolts on the first pass in sequence (1-8) to 3 N.m (27 lb in). Tighten the bolts on the second pass in sequence (1-8) to 12 N.m (106 lb in). Tighten the bolts on the final pass in sequence (1-8) to 15 N.m (11 lb ft).
11. Position the power steering pump mounting bracket.
12. Install the power steering pump mounting bracket, 3 bolts and the nut. Tighten: Tighten the power steering pump mounting bracket bolts and the nut to 41 N.m (30 lb ft). Tighten the power steering pump rear bracket nut to 41 N.m (30 lb ft). Tighten the power steering pump mounting bracket bolts and the nut and the power steering pump rear bracket nut to 41 N.m (30 lb ft).
13. Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
14. Install the A/C compressor discharge hose from the vehicle. Refer to «Discharge Hose Replacement (4.8L, 5.3L, 6.0L )»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Discharge Hose Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
15. Install the A/C compressor suction hose from the vehicle. Refer to «Suction Hose Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
16. Remove the spark plug for number one cylinder.
17. Rotate the crankshaft until number one cylinder is in the compression stroke.
18. Align the 2 reference marks on the crankshaft balancer (1) and (4) with the 2 alignment marks (2) and (3) on the front cover.
19. Install the spark plug. Refer to «Spark Plug Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
20. Install the distributor. Refer to «Distributor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
21. Install the upper intake. Refer to «Intake Manifold Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
22. Install the accelerator control cable bracket, studs, and nuts to the intake manifold and the throttle body. Tighten: Tighten the accelerator control cable bracket nuts and studs to 12 N.m (106 lb in).
23. Install the water pump inlet hose to the intake manifold.
24. Install the heater hoses. Refer to «Heater Hose Replacement - Inlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) and «Heater Hose Replacement - Outlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
25. Install the radiator inlet hose to the water outlet. Refer to «Radiator Hose Replacement - Inlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
26. Connect the following electrical connectors: The fuel meter body assembly connector (1) The evaporative emission (EVAP) canister purge solenoid valve (2) The manifold absolute pressure (MAP) sensor (3) The A/C high pressure switch (4), if equipped
27. Connect the following electrical connectors: The A/C compressor clutch (1), if equipped The EGR valve (2) The ECT sensor (3)
28. Install the ground wire (4) and the nut to the water outlet stud. Tighten: Tighten the ground wire nut to 10 N.m (88 lb in).
29. Install the cruise control cable, if equipped to the throttle shaft and the accelerator control cable bracket. Refer to «Cruise Control Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cruise-control-systems/#cruise-control-system) in Cruise Control.
30. Install the accelerator control cable to the throttle shaft and the accelerator control cable bracket. Refer to «Accelerator Controls Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
31. Refill the cooling system. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
32. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls-4.3L.
33. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
34. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
3. Remove the positive crankcase ventilation hose from the valve rocker arm cover.
4. Disconnect the engine coolant temperature (ECT) gage sensor electrical connector.
5. Remove the ECT gage sensor connector from the bracket.
6. Remove the spark plug wires for the left side of the engine from the distributor cap.
7. Remove the air conditioning compressor discharge hose, if equipped. Refer to «Discharge Hose Replacement (4.8L, 5.3L, 6.0L )»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Discharge Hose Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
8. Remove the air conditioning compressor suction hose, if equipped. Refer to «Suction Hose Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
9. Remove the valve rocker arm cover bolts.
10. Remove the valve rocker arm cover.

1. Install the NEW valve rocker arm cover gasket into the groove of the valve rocker arm cover.
2. Install the NEW valve rocker arm cover bolt grommets into the valve rocker arm cover.
3. Install the valve rocker arm cover onto the cylinder head.
4. Install the valve rocker arm cover bolts. Tighten: Tighten the valve rocker arm cover bolts to 12 N.m (106 lb in).
5. Install the air conditioning compressor discharge hose, if equipped. Refer to «Discharge Hose Replacement (4.8L, 5.3L, 6.0L )»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Discharge Hose Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
6. Install the air conditioning compressor suction hose, if equipped. Refer to «Suction Hose Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
7. Connect the spark plug wires to the distributor cap.
8. Install the ECT gage sensor electrical connector to the bracket.
9. Connect the ECT gage sensor electrical connector.
10. Install the PCV hose to the valve rocker arm cover.
11. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
12. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.

1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
3. Remove the coolant reservoir bolt and set the reservoir aside.
4. Remove the spark plug wires for the right side of the engine from the distributor cap.
5. Remove the positive crankcase ventilation (PCV) tube from the valve rocker arm cover and the air inlet duct.
6. Move the engine wiring harness aside.
7. Remove the screw holding the oil fill tube to the oil fill tube lower support.
8. Remove the oil fill tube from the right valve rocker arm cover and move aside.
9. Remove the valve rocker arm cover bolts.
10. Remove the valve rocker arm cover.

1. Install the NEW valve rocker arm cover gasket into the groove of the valve rocker arm cover.
2. Install the NEW valve rocker arm cover bolt grommets into the valve rocker arm cover.
3. Install the valve rocker arm cover onto the cylinder head.
4. Install the valve rocker arm cover bolts. Tighten: Tighten the valve rocker arm cover bolts to 12 N.m (106 lb in).
5. Install the oil fill tube in the right valve rocker arm cover.
6. Install the oil fill tube and bolt to the oil fill tube lower support. Tighten: Tighten the oil fill tube to lower support bolt to 5 N.m (44 lb in).
7. Install the PCV hose in the valve rocker arm cover and to the air inlet duct.
8. Connect the spark plug wires to the distributor cap.
9. Position the engine wiring harness.
10. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
11. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
12. Reposition the coolant reservoir and install the bolt. Tighten: Tighten the bolt to 11 N.m (97 lb in).

1. Remove the valve rocker arm cover. Refer to «Valve Rocker Arm Cover Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Valve Rocker Arm Cover Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the valve rocker arms.
3. Remove the valve rocker arm supports.
4. Remove the valve pushrods.
5. Clean and inspect the valve rocker arm and the valve pushrod. Refer to «Valve Rocker Arm and Push Rods Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Scheme 14

Scheme 15

1. Install the valve pushrods.
2. Install the valve rocker arm supports.
3. Apply prelube GM P/N 12345501 (Canadian P/N 992704) or equivalent to the following valve rocker arm contact surfaces: Valve pushrod socket (1) Roller pivot (2) Valve stem tip (3)
4. Install the valve rocker arm assemblies as follows: Finger start the bolt at location (1) Finger start the bolt at location (2) Finger start the bolt at location (3) Finger start the remaining valve rocker arm bolts
5. Rotate the crankshaft balancer to position the crankshaft balancer alignment mark (1) 57-63 degrees clockwise or counterclockwise from the engine front cover alignment tab (2).
6. Tighten the valve rocker arm bolts. Tighten: Tighten the valve rocker arm bolts to 30 N.m (22 lb ft).
7. Install the valve rocker arm cover. Refer to «Valve Rocker Arm Cover Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Valve Rocker Arm Cover Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Valve Stem Oil Seal and Valve Spring Replacement

Tools Required

1. J 22794 Spark Plug Port Adapter. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 38606 Valve Spring Compressor. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. J 5892-D Valve Spring Compressor. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. J 42073 Valve Stem Seal Installer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Remove the valve rocker arm cover. Refer to «Valve Rocker Arm Cover Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Valve Rocker Arm Cover Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l)
2. Remove the required valve rocker arms. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Remove the required spark plugs. Refer to «Spark Plug Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
4. Install the J 22794 into the spark plug hole. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Connect a shop air supply hose and apply compressed air in order to hold the valves in place.
6. Remove a bolt from a valve rocker arm.
7. Install a flat washer on the bolt.
8. Install the bolt in the valve rocker arm bolt hole for the valve spring requiring removal.
9. Use the J 5892-D in order to compress the valve spring. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Hook the slotted end of J 5892-D under the washer on the valve rocker arm bolt. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Apply steady pressure on the valve spring cap until the valve keys are accessible.
10. Use J 38606 when J 5892-D will not fit. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
11. Remove the valve keys (1).
12. Carefully release the valve spring tension.
13. Remove the J 5892-D or J 38606 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
14. Remove the valve spring cap (2) and valve spring (3).
15. Remove the valve stem oil seal (4).

Scheme 16

1. Assemble the valve into the proper valve guide.
2. Select the proper valve stem oil seal for the specific valve guide.
3. Lubricate the valve stem oil seal and the outside diameter of the valve guide with clean engine oil.
4. Assemble the valve stem oil seal onto the valve stem.
5. Using the J 42073 , install the valve stem oil seal onto the valve guide. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tap the valve stem oil seal onto the valve guide until the J 42073 bottoms against the valve spring seat. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Inspect the valve stem oil seal. The valve stem oil seal should not be bottomed against the valve guide. There should be a 1-2 mm (0.03937-0.07874 in) gap between the bottom edge of the valve stem oil seal and the valve guide.
6. Install the valve spring (3).
7. Install the valve spring cap (2) onto the valve spring (3), over the valve stem.
8. Use the J 5892-D in order to compress the valve spring. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Hook the slotted end of J 5892-D under the washer on the valve rocker arm bolt. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
9. Apply steady pressure on the valve spring cap until the valve keys are accessible.
10. Use the J 38606 if the clearance does not permit use of the J 5892-D . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
11. Install the valve stem O-ring seal.
12. Install the valve stem keys. Use grease in order to hold the valve stem keys in place.
13. Carefully release the valve spring pressure, making sure the valve stem keys stay in place.
14. Remove the J 5892-D or the J 38606 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Look to ensure that the valve stem keys seat properly in the upper groove of the valve stem. Tap the end of the valve stem with a plastic faced hammer in order to seat the valve stem keys, if necessary.
15. Remove the J 22794 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
16. Install the spark plugs. Refer to «Spark Plug Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
17. Install the valve rocker arms to the cylinder head. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
18. Install the valve rocker arm cover. Refer to «Valve Rocker Arm Cover Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Valve Rocker Arm Cover Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Tools Required

J 3049-A Valve Lifter Remover. See Special Tools and Equipment .

1. Remove the lower intake manifold. Refer to «Intake Manifold Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the valve rocker arms and the valve pushrods. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Remove the bolts and valve lifter pushrod guide.
4. Remove the valve lifters.
5. Use the J 3049-A in order to remove the stuck valve lifters. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
6. Use a cleaning solvent and a shop towel to clean any varnish from the valve lifter bores.
7. Inspect the valve lifter bores for excessive wear or scoring. Replace the engine block if there is excessive wear or deep scoring.
8. Inspect the camshaft for wear or damage. If the wear is questionable remove the camshaft and inspect. Refer to «Camshaft and Bearings Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__camshaft-and-bearings-cleaning-and-inspection) .
9. Clean and inspect the valve lifters and the valve pushrod guide. Refer to «Valve Lifters and Guides Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Apply lubricant GM P/N 12345501 (Canadian P/N 992704) or equivalent to the valve lifter rollers.
2. Install the valve lifters.
3. Install the valve lifter pushrod guides. Tighten: Tighten the valve lifter pushrod guide bolts to 16 N.m (12 lb ft).
4. Install the valve rocker arms and pushrods. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Install the lower intake manifold. Refer to «Intake Manifold Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

J 45059 Angle Meter. See Special Tools and Equipment .

1. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
3. Drain the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
4. Remove the fan shroud. Refer to «Fan Shroud Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) and to «Fan Shroud Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
5. Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
6. Remove the air conditioning compressor discharge hose, if equipped. Refer to «Discharge Hose Replacement (4.8L, 5.3L, 6.0L )»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Discharge Hose Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
7. Remove the air conditioning compressor suction hose, if equipped. Refer to «Suction Hose Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
8. Remove the mounting bolts (2) for the air conditioning compressor (1), if equipped.
9. Move the compressor aside and support.
10. Remove the drive belt idler pulley if not equipped with A/C. Refer to «Drive Belt Idler Pulley Replacement - without Air Conditioning»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
11. Remove the power steering pump pulley. Refer to «Power Steering Pulley Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/manual-power-steering/#power-steering-system__power-steering-pulley-replacement) in Power Steering Systems.
12. Remove the 3 bolts holding the power steering pump to the power steering pump mounting bracket. The power steering pump can remain on the engine.
13. Remove the 3 bolts and nut holding the power steering pump mounting bracket to the engine.
14. Slide the power steering pump mounting bracket off the stud and power steering pump.
15. Remove the power steering pump mounting bracket stud from the cylinder head.
16. Remove the lower intake manifold. Refer to «Intake Manifold Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
17. Remove the exhaust manifold. Refer to «Exhaust Manifold Replacement - Left (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Replacement - Left (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
18. Remove the ground wires at the rear of the cylinder head.
19. Remove the transmission control cable bracket.
20. Remove the valve pushrods. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
21. Remove the engine coolant temperature sensor if applicable.
22. Remove the engine coolant temperature gage sensor if applicable.
23. Remove the spark plugs.
24. Remove the bolts and the spark plug wire support.
25. Remove the cylinder head bolts.
26. Remove the cylinder head.
27. Remove and discard the cylinder head gasket.
28. Remove the dowel pins cylinder head locator if required.
29. Clean the engine block and the cylinder head sealing surfaces.
30. Clean the cylinder head bolts and the engine block bolt holes.
31. For further service to the cylinder head refer to the following: «Cylinder Head Disassemble»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__cylinder-head-disassemble) , «Cylinder Head Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__cylinder-head-cleaning-and-inspection) , «Valve Guide Reaming/Valve and Seat Grinding»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Cylinder Head Assemble»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__cylinder-head-assemble) .

1. Clean the cylinder head gasket surfaces on the engine block.
2. Inspect the dowel pins (cylinder head locator) for proper installation.
3. Clean the cylinder head gasket surfaces on the cylinder head.
4. Install the NEW cylinder head gasket in position over the dowel pins, cylinder head locator.
5. Install the cylinder head onto the engine block. Guide the cylinder head carefully into place over the dowel pins and the cylinder head gasket.
6. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent to the threads of the cylinder head bolts.
7. Install the cylinder head bolts finger tight.
8. Tighten the cylinder head bolts in sequence on the first pass. Tighten: Tighten the bolts in sequence on the first pass to 30 N.m (22 lb ft).
9. Using the J 45059 tighten the cylinder head bolts in sequence on the final pass. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten: Tighten the long bolts (1, 4, 5, 8, and 9) on the final pass in sequence to 75 degrees. Tighten the medium bolts (12, and 13) on the final pass in sequence to 65 degrees. Tighten the short bolts (2, 3, 6, 7, 10, and 11) on the final pass in sequence to 55 degrees.
10. Install the spark plug wire support and bolts. Tighten: Tighten the spark plug wire support bolts to 12 N.m (106 lb in).
11. Measure the NEW spark plugs for the proper gap. Adjust the spark plug gap if necessary. Specification: Spark plug gap: 1.52 mm (0.060 in).
12. Install the spark plugs. Tighten: Tighten the spark plugs for a USED cylinder head to 15 N.m (11 lb ft). Tighten the spark plugs for the initial installation of a NEW cylinder head to 30 N.m (22 lb ft).
13. If reusing the engine coolant temperature gage sensor, if applicable, apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent to the threads of the engine coolant temperature gage sensor.
14. Install the engine coolant temperature gage sensor, if applicable. Tighten: Tighten the engine coolant temperature gage sensor to 20 N.m (15 lb ft).
15. If reusing the engine coolant temperature sensor, if applicable, apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent to the threads of the engine coolant temperature gage sensor.
16. Install the engine coolant temperature sensor, if applicable. Tighten: Tighten the engine coolant temperature sensor to 20 N.m (15 lb ft).
17. Install the valve pushrods. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
18. Install the ground wires and nut at the rear of the cylinder head. Tighten: Tighten the ground wire nut to 10 N.m (88 lb in).
19. Install the transmission control cable bracket and bolts at the rear of the cylinder head. Tighten: Tighten the transmission control cable bracket bolts to 40 N.m (30 lb ft).
20. Install the exhaust manifold. Refer to «Exhaust Manifold Replacement - Left (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Replacement - Left (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
21. Install the lower intake manifold. Refer to «Intake Manifold Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
22. Install the stud for the power steering pump mounting bracket to the cylinder head. Tighten: Tighten the power steering pump mounting bracket stud to 20 N.m (15 lb ft).
23. Slide the power steering pump mounting bracket on the stud and the power steering pump.
24. Install the 3 bolts and the nut. Tighten: Tighten the power steering pump mounting bolts and the nut to 41 N.m (30 lb ft).
25. Install the 3 bolts for the power steering pump. Tighten: Tighten the power steering pump mounting bracket to the power steering pump bolts to 50 N.m (37 lb ft).
26. Install the power steering pump pulley. Refer to «Power Steering Pulley Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/manual-power-steering/#power-steering-system__power-steering-pulley-replacement) in Power Steering Systems.
27. Install the air conditioning compressor, if equipped. Refer to «Compressor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Compressor Replacement (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
28. Install the air conditioning compressor discharge hose, if equipped. Refer to «Discharge Hose Replacement (4.8L, 5.3L, 6.0L )»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Discharge Hose Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
29. Install the air conditioning compressor suction hose, if equipped. Refer to «Suction Hose Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation and Air Conditioning.
30. Install the drive belt idler pulley if not equipped with A/C. Refer to «Drive Belt Idler Pulley Replacement - without Air Conditioning»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
31. Install the fan shroud. Refer to «Fan Shroud Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) and to «Fan Shroud Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
32. Fill the engine coolant system. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
33. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
34. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

J 45059 Angle Meter. See Special Tools and Equipment .

1. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
3. Drain the engine coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
4. Remove the fan shroud. Refer to «Fan Shroud Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) and to «Fan Shroud Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
5. Remove the generator mounting bracket. Refer to «Generator Bracket Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
6. Remove the generator mounting bracket stud from the cylinder head.
7. Remove the lower intake manifold. Refer to «Intake Manifold Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
8. Remove the exhaust manifold. Refer to «Exhaust Manifold Replacement - Right (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Replacement - Right (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
9. Remove the ground wires at the rear of the cylinder head.
10. Remove the valve pushrods. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
11. Remove the spark plugs.
12. Remove the rear bolt and the spark plug wire support.
13. Remove the cylinder head bolts.
14. Remove the cylinder head.
15. Remove and discard the cylinder head gasket.
16. Remove the dowel pins (cylinder head locator), if required.
17. Clean the engine block and the cylinder head sealing surfaces.
18. Clean the cylinder head bolts and the engine block bolt holes.
19. For further service to the cylinder head refer to the following: «Cylinder Head Disassemble»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__cylinder-head-disassemble) , «Cylinder Head Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__cylinder-head-cleaning-and-inspection) , «Valve Guide Reaming/Valve and Seat Grinding»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) or «Cylinder Head Assemble»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__cylinder-head-assemble) .

1. Clean the cylinder head gasket surfaces on the engine block.
2. Inspect the dowel pins (cylinder head locator) for proper installation.
3. Clean the cylinder head gasket surfaces on the cylinder head.
4. Install the NEW cylinder head gasket in position over the dowel pins cylinder head locator.
5. Install the cylinder head onto the engine block. Guide the cylinder head carefully into place over the dowel pins and the cylinder head gasket.
6. Apply sealant GM P/N 12346004 (Canadian P/N 12346004) or equivalent to the threads of the cylinder head bolts.
7. Install the cylinder head bolts finger tight.
8. Tighten the cylinder head bolts in sequence on the first pass. Tighten: Tighten the bolts in sequence on the first pass to 30 N.m (22 lb ft).
9. Using the J 45059 tighten the cylinder head bolts in sequence on the final pass. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten: Tighten the long bolts (1, 4, 5, 8, and 9) on the final pass in sequence to 75 degrees. Tighten the medium bolts (12 and 13) on the final pass in sequence to 65 degrees. Tighten the short bolts (2, 3, 6, 7, 10, and 11) on the final pass in sequence to 55 degrees.
10. Install the spark plug wire support and bolts. Tighten: Tighten only the rear spark plug wire support bolt to 12 N.m (106 lb in).
11. Remove the front spark plug wire support bolt. The front spark plug wire support bolt is used to fasten the oil level indicator tube, and will be installed within the oil level indicator tube installation procedure.
12. Measure the NEW spark plugs for the proper gap. Adjust the spark plug gap if necessary. Specification: Spark plug gap to 1.52 mm (0.060 in).
13. Install the spark plugs. Tighten: Tighten the spark plugs for a USED cylinder head to 15 N.m (11 lb ft). Tighten the spark plugs for the initial installation of a NEW cylinder head to 30 N.m (22 lb ft).
14. Install the valve pushrods. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
15. Install the ground wires and nut at the rear of the cylinder head. Tighten: Tighten the ground wire nut to 10 N.m (88 lb in).
16. Install the exhaust manifold. Refer to «Exhaust Manifold Replacement - Right (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Replacement - Right (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
17. Install the intake manifold. Refer to «Intake Manifold Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
18. Install the stud for the generator mounting bracket to the cylinder head. Tighten: Tighten the generator mounting bracket stud to 20 N.m (15 lb ft).
19. Install the generator mounting bracket. Refer to «Generator Bracket Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
20. Install the fan shroud. Refer to «Fan Shroud Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) and to «Fan Shroud Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
21. Fill the engine coolant system. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
22. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
23. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

J 23523-F Balancer Remover and Installer. See Special Tools and Equipment .

1. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Remove the fan shroud assembly. Refer to «Fan Shroud Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Remove the crankshaft balancer bolt and washer.
5. Remove the bolts and the crankshaft pulley.
6. Use the J 23523-F in order to remove the crankshaft balancer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install the J 23523-F plate and bolts onto the crankshaft balancer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten: Tighten the bolts to 25 N.m (18 lb ft). Install the J 23523-F forcing screw into the plate. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Rotate the J 23523-F forcing screw clockwise in order to remove the crankshaft balancer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
7. Remove the J 23523-F from the crankshaft balancer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
8. Note the position and length of any front groove pins (crankshaft balancer), if applicable.
9. Clean and inspect all parts. Refer to «Crankshaft Balancer Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Scheme 17

1. Apply a small amount of grease to the crankshaft front cover oil seal sealing surface.
2. Look to ensure that the front groove pin (crankshaft balancer) is installed in the proper location if applicable. The length and location of the pins must be the same as the original length and location.
3. Apply a small amount of adhesive GM P/N 12346141 (Canadian P/N 1093433) or equivalent onto the crankshaft balancer keyway in order to seal the crankshaft balancer keyway and crankshaft joint.
4. Align the keyway of the crankshaft balancer with the crankshaft balancer key.
5. Install the crankshaft balancer onto the end of the crankshaft.
6. Use the J 23523-F in order to press the crankshaft balancer onto the crankshaft. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . NOTE: Refer to «Fastener Notice»(/chevrolet/chevy-express-g3500/1996-2012/remont/oem-general-information/#cautions-and-notices__fastener-notice) in Cautions and Notices. Install the J 23523-F plate and bolts onto the front of the crankshaft balancer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten: Tighten the plate bolts to 25 N.m (18 lb ft). Install the J 23523-F screw into the end for the crankshaft. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install the J 23523-F bearing, the washer, and the nut onto the screw. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Rotate the J 23523-F nut clockwise until the crankshaft balancer hub is completely seated against the crankshaft position sensor reluctor ring. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
7. Remove the J 23523-F . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
8. Install the crankshaft pulley and bolts. Tighten: Tighten the crankshaft pulley bolts to 58 N.m (43 lb ft).
9. Ensure that the crown of the crankshaft balancer washer (2) is faced away from the engine.
10. Install the crankshaft balancer washer and the bolt. Tighten: Tighten the crankshaft balancer bolt to 95 N.m (70 lb ft).
11. Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
12. Install the fan shroud assembly. Refer to «Fan Shroud Replacement - Lower»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
13. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

J 35468 Cover Aligner/Seal Installer. See Special Tools and Equipment .

1. Remove the crankshaft balancer. Refer to «Crankshaft Balancer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Use a suitable prying tool to remove the crankshaft front oil seal.
3. Inspect the engine front cover seal bore for damage.
4. Inspect the crankshaft balancer seal area. Refer to «Crankshaft Balancer Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Lubricate the exterior of the crankshaft front oil seal with clean engine oil.
2. Use the J 35468 with a hammer in order to install the crankshaft front oil seal. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Inspect to ensure the crankshaft front oil seal is flush and square to the engine front cover.
4. Install the crankshaft balancer. Refer to «Crankshaft Balancer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Remove the engine oil pan. Refer to «Oil Pan Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the crankshaft balancer. Refer to «Crankshaft Balancer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Remove the water pump. Refer to «Water Pump Replacement (4.3L Engine)»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Water Pump Replacement (4.8L, 5.3L, and 6.0L Engines)»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
4. Remove the crankshaft position (CKP) sensor. Refer to «Crankshaft Position (CKP) Sensor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls.
5. Remove the crankshaft position sensor seal (O-ring).
6. Discard the crankshaft position sensor seal (O-ring).
7. Remove the engine front cover bolts.
8. Remove the engine front cover.
9. Discard the engine front cover.
10. Clean all sealing surfaces.

1. Install the NEW engine front cover.
2. Install the engine front cover bolts. Tighten: Tighten the bolts to 12 N.m (106 lb in).
3. Lubricate the NEW crankshaft position sensor seal (O-ring) with clean engine oil.
4. Install the NEW crankshaft position sensor seal (O-ring) onto the crankshaft position sensor.
5. Install the CKP sensor. Refer to «Crankshaft Position (CKP) Sensor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls.
6. Install the engine oil pan. Refer to «Oil Pan Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
7. Install the water pump. Refer to «Water Pump Replacement (4.3L Engine)»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Water Pump Replacement (4.8L, 5.3L, and 6.0L Engines)»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
8. Install the crankshaft balancer. Refer to «Crankshaft Balancer Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

J 5590 Pinion Bearing Race Installer - Rear. See Special Tools and Equipment .

1. Remove the engine front cover. Refer to «Engine Front Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the crankshaft position sensor reluctor ring.

Scheme 18

1. Install the crankshaft position sensor reluctor ring. Align the keyway on the crankshaft position sensor reluctor ring with the crankshaft balancer key in the crankshaft. Use the J 5590 in order to push the crankshaft position sensor reluctor ring onto the crankshaft until completely seated against the crankshaft sprocket. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Install the engine front cover. Refer to «Engine Front Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Timing Chain, Sprockets, and/or Tensioner Replacement

Tools Required

1. J 5590 Rear Pinion Bearing Race Installer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 5825-A Crankshaft Gear Remover. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Note. In order to rotate the engine install a bolt with the same threads as the crankshaft, but do not use the crankshaft balancer bolt or a bolt longer than 1 inch, in the crankshaft. Failing to do so will cause damage to the bolt threads and the crankshaft threaded hole when removing the bolt.

Scheme 19

1. Remove the crankshaft position (CKP) sensor reluctor ring. Refer to «Crankshaft Position (CKP) Reluctor Ring Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Install a 7/16-20 x 1 inch bolt into the end of the crankshaft.
3. Rotate the crankshaft until: The timing marks on both sprockets line up. The number 4 cylinder is at top dead center (TDC) of the compression stroke.
4. Unsnap the timing chain tensioner shoe from the pin (1).
5. Remove the camshaft sprocket bolts.
6. Remove the camshaft sprocket and the camshaft timing chain.
7. Using J 5825-A and an open end wrench, remove the crankshaft sprocket. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
8. Remove the crankshaft balancer key.
9. If necessary, remove the timing chain tensioner bracket bolt and bracket.
10. Clean and inspect the timing chain and sprockets, if necessary. Refer to «Timing Chain and Sprockets Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. If necessary, install the timing chain tensioner bracket and bolt. Tighten: Tighten the bolt to 12 N.m (106 lb in).
2. Install the key into the crankshaft keyway. The crankshaft balancer key should be parallel to the crankshaft or with a slight incline.
3. Align the keyway of the crankshaft sprocket with the crankshaft balancer key.
4. Using J 5590 , install the crankshaft sprocket. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Install the camshaft sprocket and the camshaft timing chain. Wrap the timing chain around the crankshaft sprocket and position to the driver's side of the engine.
6. Install the timing chain tensioner shoe onto the bracket and position the top of the shoe under the tab at the top of the bracket.
7. Insert the camshaft timing chain sprocket into the timing chain and position so when the camshaft timing chain sprocket is installed on the camshaft, the camshaft timing marks will line up. IMPORTANT: Do not use a hammer to install the camshaft sprocket onto the camshaft. To do so may dislodge the expansion cup plug.
8. Install the camshaft sprocket bolts. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
9. Ensure that the crankshaft sprocket is aligned at the 12 o'clock position and camshaft sprocket is aligned at the 6 o'clock position.
10. Remove the bolt that was installed in the end of the crankshaft.
11. Install the CKP sensor reluctor ring. Refer to «Crankshaft Position (CKP) Reluctor Ring Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Balance Shaft Replacement

Tools Required

1. J 8092 Universal Driver Handle. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 45059 Angle Meter. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. J 36996 Balance Shaft Installer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Remove the radiator. Refer to «Radiator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
2. Remove the A/C condenser, if equipped. Refer to «Condenser Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
3. Remove the valve lifter pushrod guide. Refer to «Valve Lifter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Remove the camshaft timing chain and sprockets. Refer to «Timing Chain, Sprockets, and/or Tensioner Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__timing-chain-sprockets-andor-tensioner-replacement) .
5. Remove the balance shaft drive gear.
6. Remove the balance shaft driven gear bolt from the balance shaft. Use a wrench in order to secure the balance shaft. Place the wrench onto the balance shaft near to the balance shaft front bearing. Remove the balance shaft bolt. Remove the wrench from the balance shaft.
7. Remove the balance shaft driven gear from the balance shaft.
8. Remove the bolts and the balance shaft retainer.
9. Use a soft-faced hammer in order to remove the balance shaft from the engine block.
10. Clean and inspect the balance shaft. Refer to «Balance Shaft Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Apply clean engine oil GM P/N 12345610 (Canadian P/N 993193) or equivalent to the balance shaft front bearing.
2. Use the J 36996 and the J 8092 in order to install the balance shaft. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Install the balance shaft retainer and bolts. Tighten: Tighten the bolts to 12 N.m (106 lb in).
4. Install the balance shaft driven gear onto the balance shaft.
5. If reusing the fastener, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the balance shaft driven gear bolt.
6. Install the balance shaft driven gear bolt. Use a wrench to secure the balance shaft. Place the wrench onto the balance shaft near to the balance shaft front bearing. Install the balance shaft driven gear bolt. Tighten: Tighten the balance shaft driven gear bolt on the first pass to 20 N.m (15 lb ft). Tighten the balance shaft driven gear bolt on the final pass using the J 45059 an additional 35 degrees. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
7. Remove the wrench from the balance shaft.
8. Rotate the balance shaft by hand in order to ensure that there is clearance between the balance shaft and the valve lifter pushrod guide. If the balance shaft does not rotate freely, check to ensure that the retaining ring on the balance shaft front bearing is seated on the case.
9. Install the balance shaft drive gear. DO NOT install the camshaft sprocket bolts at this time.
10. Rotate the engine camshaft so that the timing mark on the balance shaft drive gear is in the 12 o'clock position.
11. Remove the balance shaft drive gear.
12. Rotate the balance shaft so that the timing mark on the balance shaft driven gear is in the 6 o'clock position.
13. Position the balance shaft drive gear onto the engine camshaft.
14. Look to ensure that the balance shaft drive gear and the balance shaft driven gear timing marks are aligned.
15. Install the camshaft timing chain and the camshaft sprocket. Refer to «Timing Chain, Sprockets, and/or Tensioner Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__timing-chain-sprockets-andor-tensioner-replacement) .
16. Install the crankshaft position reluctor ring and the engine front cover. Refer to «Crankshaft Position (CKP) Reluctor Ring Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
17. Install the valve lifter pushrod guide. Refer to «Valve Lifter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
18. Install the A/C condenser, if equipped. Refer to «Condenser Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
19. Install the radiator. Refer to «Radiator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.

Balance Shaft Bearing and/or Bushing Replacement

Tools Required

1. J 26941 Bushing/Bearing Remover. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 38834 Balance Shaft Service Kit. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Remove the balance shaft. Refer to «Balance Shaft Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__balance-shaft-replacement) .
2. Use the J 38834 and the J 26941 in order to remove the balance shaft rear bearing. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install J 26941 legs behind the balance shaft rear bearing and secure. Install the J 38834-1 with the short threaded end through the balance shaft bore in the front of the engine block. Install the J 38834-1 into J 26941 . Slide the J 38834-2 onto the J 38834-1 and into the balance shaft bore of the engine block. Install the J 38834 bearing, washer, and nut onto the J 38834-1. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Using a wrench secure the J 38834-1 and then rotate the J 38834 nut clockwise until the balance shaft rear bearing is removed from the engine block. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Remove the J 26941 from the balance shaft rear bearing.
3. Discard the balance shaft rear bearing.

1. Use the J 38834 in order to install the balance shaft rear bearing. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install the J 38834-3 onto the short threaded end of the J 38834-1. Install the J 38834 nut, the washer, and the bearing on the long threaded end of the J 38834-1. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install the J 38834-2 onto the J 38834-1 so that the smaller diameter of the J 38834-2 will be facing the front of the engine block. Install the J 38834-2 on the inside of the balance shaft front bearing bore. Lubricate the NEW balance shaft rear bearing with clean engine oil. Install the balance shaft rear bearing onto the J 38834-2. Align the balance shaft rear bearing for installation. Using a wrench secure the J 38834-1 into place. Rotate the J 38834 nut until the balance shaft rear bearing is properly and completely pushed into the balance shaft rear bearing bore. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the J 38834 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Install the balance shaft. Refer to «Balance Shaft Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__balance-shaft-replacement) .

Scheme 20

1. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
3. Remove the radiator. Refer to «Radiator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
4. Remove the A/C condenser. Refer to «Condenser Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
5. Remove the engine cooling fan. Refer to «Fan Clutch Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
6. Remove the valve lifters. Refer to «Valve Lifter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
7. Remove the timing chain and the camshaft sprocket. Refer to «Timing Chain, Sprockets, and/or Tensioner Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__timing-chain-sprockets-andor-tensioner-replacement) .
8. Remove the balance shaft drive gear.
9. Remove the camshaft retainer bolts and retainer.
10. Remove the engine camshaft. Install the three 5/16-18 x 4.0 inch bolts into the engine camshaft front bolt holes. Using the bolts as a handle, carefully rotate and pull the engine camshaft out of the camshaft bearings. Remove the bolts from the front of the engine camshaft.
11. Clean and inspect the camshaft and the bearings. Refer to «Camshaft and Bearings Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__camshaft-and-bearings-cleaning-and-inspection) .

1. Apply clean engine oil GM P/N 12345610 (Canadian P/N 993193) or equivalent, or engine oil supplement GM P/N 1052367 (Canadian P/N 992367) or equivalent to the following components: The engine camshaft lobes The camshaft bearing journals The camshaft bearings
2. Install three 5/16-18 x 4.0 inch bolts into the engine camshaft front bolt holes.
3. Use the bolts as a handle in order to install the engine camshaft.
4. Remove the 3 bolts from the front of the engine camshaft.
5. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the camshaft retainer bolts.
6. Install the camshaft retainer and bolts. Tighten: Tighten the camshaft retainer bolts to 12 N.m (106 lb in).
7. Install the balance shaft drive gear. Refer to «Balance Shaft Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__balance-shaft-replacement) for alignment of the balance shaft drive gear and the driven gear.
8. Install the timing chain and camshaft sprocket. Refer to «Timing Chain, Sprockets, and/or Tensioner Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__timing-chain-sprockets-andor-tensioner-replacement) .
9. Install the valve lifters. Refer to «Valve Lifter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
10. Install the A/C condenser. Refer to «Condenser Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
11. Install the engine cooling fan. Refer to «Fan Clutch Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
12. Install the radiator. Refer to «Radiator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
13. Fill the engine cooling system. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
14. Recharge the air conditioning system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) in Heating, Ventilation, and Air Conditioning.
15. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
16. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Position a suitable container to catch the engine oil.
3. Remove the oil filter.
4. Disconnect the engine oil cooler pipes from the oil filter adapter. Refer to «Engine Oil Cooler Hose/Pipe Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
5. Remove the oil filter adapter bolts.
6. Remove the oil filter adapter and the oil filter adapter gasket.
7. Discard the oil filter adapter gasket.
8. Remove the oil filter adapter seal O-ring.
9. Discard the oil filter adapter seal O-ring.

1. Install the NEW oil filter adapter seal O-ring into the groove in the oil filter adapter.
2. Install the oil filter adapter and NEW oil filter adapter gasket.
3. Install the oil filter adapter bolts. Tighten: Tighten the oil filter adapter bolts to 21 N.m (15 lb ft).
4. Install the oil cooler pipes to the oil filter adapter. Refer to «Engine Oil Cooler Hose/Pipe Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
5. Install the oil filter. Refer to «Engine Oil and Oil Filter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
6. Lower the vehicle.
7. Operate the vehicle and check for leaks.
8. Check the oil level and add as required.

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Position a suitable container to catch the engine oil.
3. Remove the oil filter.
4. Remove the oil filter adapter. Refer to «Oil Filter Adapter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Using a suitable prying tool remove the oil filter bypass valve.
6. Clean and inspect valve bore for damage.

Scheme 21

1. Install a NEW oil filter bypass valve using the following procedure: Use a brass drift that is the same diameter as the outside diameter of the oil filter bypass valve. Install the oil filter bypass valve into the oil gallery bore until slightly below flush with the surface of the engine block. Using a pointed punch, stake the engine block area around the oil filter bypass valve. Stake in 3 locations 120 degrees apart.
2. Install the oil filter adapter. Refer to «Oil Filter Adapter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Install the oil filter. Refer to «Engine Oil and Oil Filter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Lower the vehicle.

1. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the oil pan drain plug and drain the engine oil into a suitable container.
4. Remove the oil filter.
5. Remove the oil filter adapter. Refer to «Oil Filter Adapter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
6. If equipped with AWD, remove the front differential carrier. Refer to «Differential Carrier Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/differentials-drive-axles/#front-drive-axle) in Front Drive Axle.
7. Remove the bolt holding the bracket for the starter wire and the transmission cooler pipes.
8. Remove the crankcase position (CKP) sensor wiring harness from the retainer.
9. Remove the starter. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
10. Remove the transmission cover.
11. Remove the access plugs for the oil pan rear nuts.
12. Remove the transmission to oil pan bolts.
13. Remove and discard the engine oil level sensor, if applicable.
14. Remove the oil pan bolts and nuts.
15. Remove the oil pan.
16. Remove the oil pan gasket.
17. Discard the oil pan gasket.
18. Clean all sealing surfaces on the engine and the oil pan. Refer to «Oil Pan Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Apply a 5 mm (0.197 in) wide and 25 mm (1.0 in) long bead of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent to both the right and left sides of the engine front cover to engine block junction at the oil pan sealing surfaces.
2. Apply a 5 mm (0.197 in) wide and 25 mm (1.0 in) long bead of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent to both the right and left sides of the crankshaft rear oil seal housing to engine block junction at the oil pan sealing surfaces.
3. Install the NEW oil pan gasket into the groove in the oil pan.
4. Install the oil pan onto the engine block. Press the oil pan gasket into the grooves of the engine front cover and crankshaft rear oil seal housing.
5. Slide the oil pan back against a suitable straight edge.
6. Install the oil pan bolts and nuts, but do not tighten.
7. Measure the pan-to-transmission housing clearance using a feeler gage and a straight edge. Use a feeler gage to check the clearance between the oil pan-to-transmission housing measurement points. If the clearance exceeds 0.3 mm (0.011 in) at any of the 3 oil pan-to-transmission housing measurement points (1), then repeat the step until the oil pan-to-transmission housing clearance is within the specification. The oil pan must always be forward of the rear face of the engine block.
8. Tighten the oil pan bolts and nuts in sequence (1-12). Tighten: Tighten the oil pan bolts to 25 N.m (18 lb ft).
9. Measure the clearance between the 3 oil pan-to-transmission housing measurement points in order to ensure proper alignment.
10. Install a NEW oil pan drain plug seal (O-ring) onto the oil pan drain plug.
11. Install the oil pan drain plug into the oil pan. Tighten: Tighten the oil pan drain plug to 25 N.m (18 lb ft).
12. Install the NEW engine oil level sensor, if applicable. Tighten: Tighten the engine oil level sensor to 13 N.m (115 lb in).
13. Install the transmission to oil pan bolts. Tighten: Tighten the bolts to 47 N.m (35 lb ft).
14. Install the transmission cover. Tighten: Tighten the transmission cover bolts to 12 N.m (106 lb in).
15. Install the access plugs for the oil pan rear nuts.
16. Install the starter motor. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
17. Install the bolt holding the bracket for the starter wiring harness and the transmission cooler pipes. Tighten: Tighten the bracket bolt to 9 N.m (80 lb in).
18. Install the CKP sensor wiring harness in the retainer.
19. Install the oil filter adapter. Refer to «Oil Filter Adapter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
20. Install the oil filter and the oil pan drain plug. Refer to «Engine Oil and Oil Filter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
21. If equipped with AWD, install the front differential carrier. Refer to «Differential Carrier Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/differentials-drive-axles/#front-drive-axle) in Front Drive Axle.
22. Lower the vehicle.
23. Fill the crankcase with engine oil. Refer to «Engine Oil and Oil Filter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
24. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

J 41712 Oil Pressure Switch Socket. See Special Tools and Equipment .

1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Disconnect the engine oil pressure gage sensor electrical connector.
3. Hold the engine oil pressure gage sensor fitting with a wrench.
4. Remove the engine oil pressure gage sensor using J 41712 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Remove the engine oil pressure gage sensor fitting, if necessary.

Scheme 22

1. Install the engine oil pressure gage sensor fitting, if removed. Tighten: Tighten the engine oil pressure gage sensor fitting to 15 N.m (11 lb ft). IMPORTANT: Do not loosen the sensor fitting. Do not tighten the sensor fitting more than one turn to align. Tighten the sensor fitting until properly align.
2. Install the engine oil pressure gage sensor.
3. Hold the engine oil pressure gage sensor fitting with a wrench to prevent from turning. Tighten: Using J 41712 tighten the engine oil pressure gage sensor to 30 N. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .m (22 lb ft).
4. Connect the engine oil pressure gage sensor electrical connector.
5. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
2. Remove the bolt holding the coolant recovery reservoir and set the reservoir aside.
3. Remove the oil level indicator.
4. Remove the screw holding the oil level indicator and the transmission fluid fill tube to the oil fill tube lower support.
5. Remove the top half of the oil level indicator tube from the bottom half.
6. Clean the old sealer from the tube.
7. Remove the oil level indicator tube bolt.
8. Remove the oil level indicator tube from the engine using a twisting motion.
9. Clean the old sealer from the oil level indicator tube and the engine block.

1. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent around the oil level indicator tube 13 mm (0.5 in) below the tube bead.
2. Install the oil level indicator tube into the engine block. Rotate the oil level indicator tube into position.
3. Apply sealer, GM P/N 12346004 (Canadian P/N 10953480) or equivalent, on the upper oil level indicator tube to the area where it fits into the lower half.
4. Install the oil level indicator tube upper half to the lower half.
5. Install the bolt that holds the oil level indicator tube and the transmission fluid fill tube to the oil fill tube lower support. Tighten: Tighten the oil fill level indicator tube and the transmission fluid fill tube to lower support bolt to 5 N.m (44 lb in).
6. Install the oil level indicator.
7. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
8. Position the coolant recovery reservoir and install the bolt.

1. Remove the engine oil pan. Refer to «Oil Pan Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the oil pump bolt.
3. Remove the oil pump.
4. Inspect the pins (oil pump locator) for damage, and replace the pins if required.
5. Clean and inspect all parts. Refer to «Oil Pump Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__oil-pump-cleaning-and-inspection) .

1. Inspect for properly installed pins (oil pump locator).
2. Install the oil pump.
3. Position the oil pump onto the pins.
4. Install the oil pump bolt attaching the oil pump to the rear crankshaft bearing cap. Tighten: Tighten the oil pump bolt to 90 N.m (66 lb ft).
5. Install the oil pan. Refer to «Oil Pan Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

J 35621-B Rear Main Seal Installer. See Special Tools and Equipment .

1. Remove the transmission assembly. Refer to «Transmission Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) in Automatic Transmission-4L60-E.
2. Remove the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Remove the crankshaft rear oil seal from the crankshaft rear oil seal housing. Insert a suitable tool into the access notches and then carefully pry the crankshaft rear oil seal from the crankshaft rear oil seal housing.
4. Discard the crankshaft rear oil seal.
5. Clean off any dirt or rust in the area.

1. Apply a small amount (2 to 3 drops) of clean engine oil to the bore of the crankshaft rear oil seal housing.
2. Apply a small amount (2 to 3 drops) of clean engine oil to the outside diameter of the engine flywheel pilot flange.
3. Apply a small amount (1 drop) of clean engine oil to the outside diameter of the flywheel locator pin.
4. Apply a small amount (2 to 3 drops) of clean engine oil to the crankshaft seal surface.
5. Inspect the J 35621-B flange for imperfections that may damage the crankshaft rear oil seal. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Minor imperfections may be removed with a fine grade emery cloth.
6. Remove the sleeve from the crankshaft rear oil seal.
7. Apply a small amount (2 to 3 drops) of clean engine oil to the outside diameter of the crankshaft rear oil seal.
8. Install the crankshaft rear oil seal onto the J 35621-B . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
9. Install the J 35621-B onto the rear of the crankshaft and hand tighten the tool bolts until snug. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
10. Install the crankshaft rear oil seal onto the crankshaft and into the crankshaft rear oil seal housing. Turn the J 35621-B wing nut clockwise until the crankshaft rear oil seal is installed near to flush and square to the crankshaft rear oil seal housing. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Increased resistance will be felt when the crankshaft rear oil seal has reached the bottom of the crankshaft rear oil seal housing bore. Turn the J 35621-B wing nut counterclockwise to release the. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . J 35621-B from the crankshaft rear oil seal. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Remove the J 35621-B from the crankshaft. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Wipe off any excess engine oil with a clean rag.
11. Install the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
12. Install the transmission assembly. Refer to «Transmission Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) in Automatic Transmission-4L60-E.

1. Remove the oil pan. Refer to «Oil Pan Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the transmission assembly. Refer to «Transmission Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) in Automatic Transmission - 4L60-E.
3. Remove the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Remove the bolts and the nut holding the crankshaft rear oil seal housing to the engine.
5. Remove the crankshaft rear oil seal housing.
6. Remove and discard the crankshaft rear oil seal housing gasket.
7. Clean all the sealing surfaces.
8. Inspect the crankshaft rear oil seal housing for warping, cracks, wear, or damage.

1. Install a NEW crankshaft rear oil seal housing gasket.
2. Install the NEW crankshaft rear oil seal housing with the oil seal to the engine block using the following procedure. Leave the sleeve in the crankshaft rear oil seal and use the sleeve as a guide to ease the seal lip over the end of the crankshaft. Push the crankshaft rear oil seal housing with the seal, fully onto the crankshaft until the crankshaft rear oil seal housing is against the crankshaft rear oil seal gasket and the engine.
3. Install the three bolts and the one nut to the crankshaft rear oil seal housing. Tighten: Tighten the crankshaft rear oil seal housing bolts and nut to 12 N.m (106 lb in).
4. Install the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Install the transmission assembly. Refer to «Transmission Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) in Automatic Transmission - 4L60-E.
6. Install the oil pan. Refer to «Oil Pan Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Remove the transmission assembly. Refer to «Transmission Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) in Automatic Transmission.
2. Remove the bolts and the engine flywheel.
3. Clean and inspect all parts. Refer to «Engine Flywheel Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Install the engine flywheel to the crankshaft.
2. Align the locator hole to the pin.
3. Install the engine flywheel bolts. Tighten: Tighten the engine flywheel bolts in sequence to 100 N.m (74 lb ft).
4. Install the transmission assembly. Refer to «Transmission Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) in Automatic Transmission.

J 41427 Engine Lift Bracket. See Special Tools and Equipment .

Scheme 23

1. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
2. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
3. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
4. Remove air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-48l-53l-60l-introduction) in Engine Controls - 4.3L.
5. Remove the front bumper. Refer to «Bumper Replacement - Front»(/chevrolet/chevy-express-g3500/1996-2012/remont/exterior-body-panels/#bumper-system) in Bumpers.
6. Remove the grille. Refer to «Grille Replacement (Uplevel)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) or «Grille Replacement (Base)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) in Exterior Trim.
7. Remove the radiator support. Refer to «Radiator Support Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exterior-body-panels/#body-front-end) in Body Front End.
8. Remove the A/C condenser. Refer to «Condenser Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
9. Remove the radiator. Refer to «Radiator Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
10. Remove the accelerator control cable. Refer to «Accelerator Controls Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
11. Remove the cruise control cable, if equipped from the throttle shaft and the accelerator control cable bracket. Refer to «Cruise Control Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cruise-control-systems/#cruise-control-system) in Cruise Control.
12. Remove the stud and bolt holding the ground wires to the rear of both cylinder heads.
13. Remove the nut holding the wiring harness at the transmission to engine stud.
14. Disconnect the following electrical connectors: The throttle position (TP) sensor (1) The idle air control (IAC) motor (2) The engine coolant temperature (ECT) gage sensor (3) The A/C high pressure switch (4), if equipped
15. Disconnect the following electrical connectors: The fuel meter body assembly connector (1) The EVAP canister purge solenoid valve (2) The manifold absolute pressure (MAP) sensor (3)
16. Disconnect the following electrical connectors: The distributor (2) The engine oil pressure sensor (3) The knock (KS) sensor (1)
17. Disconnect the following electrical connectors: The A/C compressor clutch (1), if equipped The EGR valve (2) The engine coolant temperature (ECT) sensor (3)
18. Remove the ground wire (4) from the stud at the water outlet.
19. Disconnect the crankshaft position (CKP) sensor (3).
20. Remove the engine wiring harness clip (1) from the stud on the generator mounting bracket.
21. Remove the engine wiring harness clip (2) at the front of the engine.
22. Move the engine wiring harness aside.
23. Remove the bolt holding the battery negative cable and the ground strap to the front of the engine.
24. Remove the generator mounting bracket.
25. Remove the heater hoses from the engine. Refer to «Heater Hose Replacement - Inlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) and «Heater Hose Replacement - Outlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
26. Remove the radiator inlet and outlet hoses. Refer to the following procedures: «Radiator Hose Replacement - Inlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling «Radiator Hose Replacement - Outlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling
27. Remove the A/C compressor Discharge Hose from the vehicle. Refer to «Discharge Hose Replacement (4.8L, 5.3L, 6.0L )»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Discharge Hose Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
28. Remove the A/C compressor Suction Hose from the vehicle. Refer to «Suction Hose Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
29. Remove the power steering pump mounting bracket.
30. Remove the power steering pump rear mounting bracket from the engine. Set the pump aside.
31. Remove the distributor. Refer to «Distributor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
32. In order to allow access for the lifting device, remove the upper intake manifold. Refer to «Intake Manifold Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
33. Remove the spark plug wire harness retainer from the exhaust gas recirculation (EGR) valve inlet pipe.
34. Remove the clamp bolt for the EGR valve inlet pipe.
35. Remove the EGR valve inlet pipe from the intake and the exhaust manifolds.
36. Remove the transmission control cable bracket from the rear of the left cylinder head.
37. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
38. Remove both exhaust manifolds. Refer to the following procedures: «Exhaust Manifold Replacement - Left (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Replacement - Left (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) in Engine Exhaust «Exhaust Manifold Replacement - Right (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Replacement - Right (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) in Engine Exhaust
39. Remove the oil pan drain plug and drain the engine oil into a suitable container.
40. Remove the engine oil filter.
41. Remove the engine oil cooler pipes from the engine. Refer to «Engine Oil Cooler Hose/Pipe Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
42. Remove the starter motor. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
43. Remove the transmission cover.
44. Remove the torque converter bolts from the flywheel through the transmission cover opening.
45. Remove the transmission cooler pipes from the engine.
46. Remove the bolts holding the transmission to the engine except the top 2 bolts.
47. Lower the vehicle.
48. Support the transmission with a strap between the frame rails or use a suitable transmission jack.
49. Install the J 41427 using the following procedure: Remove the 2 right rear lower intake manifold bolts. Install the J 41427 marked RIGHT REAR. Install the retaining bolts. Tighten: Tighten the retaining bolts to 15 N.m (11 lb ft). Remove the 2 left front lower intake manifold bolts. Install the J 41427 marked LEFT FRONT with the arrow pointing to the front of the engine. Install the retaining bolts. Tighten: Tighten the retaining bolts to 15 N.m (11 lb ft).
50. Attach a suitable engine lifting device to the J 41427.
51. Remove the engine mounts from the engine mount frame brackets. Refer to the following procedures: «Engine Mount Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) «Engine Mount Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l)
52. Remove the two remaining engine to transmission bolts.
53. Remove the engine assembly from the vehicle.

1. Install the engine assembly to the vehicle.
2. Loosely install the 2 upper transmission to engine bolts.
3. Install the engine mounts to the engine mount frame brackets. Refer to the following procedures: «Engine Mount Replacement - Left»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) «Engine Mount Replacement - Right»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l)
4. Remove the engine lifting device.
5. Remove the J 41427 from the engine.
6. Apply thread lock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the lower intake manifold bolts.
7. Install the lower intake manifold bolts. Tighten: Tighten the bolts to 3 N.m (27 lb in). Tighten the bolts to 12 N.m (106 lb in). Tighten the bolts to 15 N.m (11 lb ft).
8. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
9. Install the remaining bolts from the transmission to the engine. Refer to «Transmission Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) in Automatic Transmission - 4L60-E/4L65-E for location of the proper bolts and tightening specifications.
10. Install the bolt holding the transmission cooler pipes bracket to the oil pan. Tighten: Tighten the bolt to 9 N.m (80 lb in).
11. Install the torque converter bolts to the flywheel. Tighten: Tighten the bolts to 62 N.m (46 lb ft).
12. Install the transmission cover. Tighten: Tighten the transmission cover bolts to 12 N.m (106 lb in).
13. Install the starter motor. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
14. Install the engine oil cooler pipes to the engine. Refer to «Engine Oil Cooler Hose/Pipe Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
15. Install the exhaust manifolds. Refer to the following procedures: «Exhaust Manifold Replacement - Left (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Replacement - Left (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) in Engine Exhaust «Exhaust Manifold Replacement - Right (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Replacement - Right (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) in Engine Exhaust
16. Lower the vehicle.
17. Install the upper intake manifold to the engine. Refer to «Intake Manifold Replacement - Upper»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
18. Install the EGR valve inlet pipe. Refer to «Exhaust Gas Recirculation (EGR) Pipe Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
19. Install the spark plug wire harness retainer on the EGR valve inlet pipe.
20. Install the transmission control cable bracket to the rear of the left cylinder head. Tighten: Tighten the transmission control cable bracket bolts to 40 N.m (30 lb ft).
21. Install the distributor. Refer to «Distributor Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
22. Install the power steering pump with the rear bracket to the engine. Refer to «Power Steering Pump Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/manual-power-steering/#power-steering-system) or «Power Steering Pump Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/manual-power-steering/#power-steering-system) in Power Steering System.
23. Install the power steering pump mounting bracket.
24. Install the A/C compressor Discharge Hose from the vehicle. Refer to «Discharge Hose Replacement (4.8L, 5.3L, 6.0L )»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Discharge Hose Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
25. Install the A/C compressor Suction Hose from the vehicle. Refer to «Suction Hose Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
26. Install the radiator inlet and outlet hoses to the engine. Refer to the following procedures: «Radiator Hose Replacement - Inlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling «Radiator Hose Replacement - Outlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling
27. Install the heater hoses to the engine. Refer to «Heater Hose Replacement - Inlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) and «Heater Hose Replacement - Outlet»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
28. Install the generator mounting bracket.
29. Install the stud and bolt holding the ground wires to the rear of both cylinder heads. Tighten: Tighten the bolt and the stud to 10 N.m (88 lb in).
30. Install the nut holding the engine wiring harness at the transmission to engine stud. Tighten: Tighten the nut to 10 N.m (88 lb in).
31. Connect the crankshaft position (CKP) sensor (3).
32. Install the engine wiring harness clip (1) from the stud on the generator mounting bracket.
33. Install the engine wiring harness clip (2) at the front of the engine.
34. Connect the following electrical connectors: The fuel meter body assembly connector (1) The EVAP canister purge solenoid valve (2) The manifold absolute pressure (MAP) sensor (3)
35. Connect the following electrical connectors: The distributor (2) The engine oil pressure sensor (3) The knock (KS) sensor (1)
36. Connect the following electrical connectors: The throttle position (TP) sensor (1) The idle air control (IAC) motor (2) The engine coolant temperature (ECT) gage sensor (3) The A/C high pressure switch (4), if equipped
37. Disconnect the following electrical connectors: The A/C compressor clutch (1), if equipped The EGR valve (2) The engine coolant temperature (ECT) sensor (3)
38. Install the nut holding the ground wire (4) to the water outlet stud. Tighten: Tighten the nut to 10 N.m (88 lb in).
39. Install the bolt holding the battery negative cable and the ground strap to the front of the engine. Tighten: Tighten the bolt to 25 N.m (18 lb ft).
40. Install a NEW accelerator control cable. Refer to «Accelerator Controls Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
41. Install the cruise control cable, if equipped to the throttle shaft and the accelerator control cable bracket. Refer to «Cruise Control Cable Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cruise-control-systems/#cruise-control-system) in Cruise Control.
42. Install the fan clutch to the water pump. Refer to «Fan Clutch Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
43. Install the radiator support. Refer to «Radiator Support Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exterior-body-panels/#body-front-end) in Body Front End.
44. Install the oil filter and fill the engine with engine oil. Refer to «Engine Oil and Oil Filter Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
45. Fill the cooling system with the proper quantity and type of coolant. Refer to «Draining and Filling Cooling System»(/chevrolet/chevy-express-g3500/1996-2012/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
46. Recharge the A/C system. Refer to «Refrigerant Recovery and Recharging»(/chevrolet/chevy-express-g3500/1996-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging) in Heating, Ventilation, and Air Conditioning.
47. With the ignition OFF or disconnected, crank the engine several times. Listen for any unusual noises or evidence that any of the parts are binding.
48. Start the engine and listen for unusual noises.
49. Check the vehicle oil pressure gage or light and confirm that the engine has acceptable oil pressure. If necessary, install an oil pressure gage and measure the engine oil pressure.
50. Operate the engine at about 1,000 RPM until the engine has reached normal operating temperature.
51. Listen for improperly adjusted or sticking valves, sticking valve lifters, or other unusual noises.
52. Inspect for oil and/or coolant leaks while the engine is operating.
53. Verify that the distributor is properly positioned.
54. Perform a final inspection for the proper engine oil and coolant levels.
55. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the oil pan drain plug and drain the engine oil in a suitable container.
3. Remove the engine oil filter.
4. Inspect to ensure the engine oil filter gasket is removed.

1. Lubricate the engine oil filter gasket with clean engine oil.
2. Install the engine oil filter.
3. Follow the tightening instructions on the oil filter.
4. Install the oil pan drain plug to the oil pan. Tighten: Tighten the oil pan drain plug to 25 N.m (18 lb ft).
5. Lower the vehicle.
6. Fill the engine with the proper capacity and quality of engine oil. Refer to «Capacities - Approximate Fluid»(/chevrolet/chevy-express-g3500/1996-2012/remont/lubrication-system/#maintenance-and-lubrication__capacities-approximate-fluid) in Maintenance and Lubrication. Refer to «Explanation of Scheduled Services»(/chevrolet/chevy-express-g3500/1996-2012/remont/lubrication-system/#maintenance-and-lubrication__explanation-of-scheduled-services) in Maintenance and Lubrication.
7. Operate the engine, check for leaks and oil pressure.

Draining Fluids and Oil Filter Removal

1. Remove the oil pan drain plug and allow the engine oil to drain into a suitable container.
2. Remove the oil filter.
3. Discard the oil filter.
4. Remove both the engine block coolant drain hole plugs and allow the coolant to drain into a suitable container.

Engine Flywheel Removal

1. Remove the engine flywheel bolts.
2. Remove the engine flywheel.

Exhaust Manifold Removal - Left

1. Remove the spark plug wires from the spark plugs. Rotate the spark plug wire boot one half turn. Pull outward on the spark plug wire boot to release from the spark plug.
2. Remove the spark plug wires from the spark plug wire retainers.
3. Remove the exhaust manifold bolts and the stud.
4. Remove the spark plug wire shields, if applicable, and the exhaust manifold.
5. Remove and discard the exhaust manifold gaskets.

Exhaust Manifold Removal - Right

1. Remove the spark plug wires from the spark plugs. Rotate the spark plug wire boot one half turn. Pull outward on the spark plug wire boot to release from the spark plug.
2. Remove the spark plug wires from the spark plug wire retainers.
3. Remove the exhaust manifold bolts.
4. Remove the spark plug wire shields and the exhaust manifold.
5. Remove and discard the exhaust manifold gaskets.

Oil Level Indicator and Tube Removal

1. Remove the oil level indicator from the oil level indicator tube, if required.
2. Remove the oil level indicator tube bolt.
3. Remove the oil level indicator tube from the engine block.

Water Pump Removal

Tools Required: J 41240 Fan Clutch Remover and Installer. See Special Tools and Equipment .

1. Remove the bolts and the fan and water pump pulley using the J 41240 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the clamps and the water pump inlet hose.
3. Remove the water pump bolts.
4. Remove the water pump.
5. Remove the water pump gaskets.
6. Discard the water pump gaskets.

Crankshaft Balancer Removal

Tools Required: J 23523-F Balancer Remover and Installer. See Special Tools and Equipment .

1. Remove the crankshaft balancer bolt and washer.
2. Remove the bolts and the crankshaft pulley.
3. Use the J 23523-F in order to remove the crankshaft balancer. Install the J 23523-F plate and bolts onto the crankshaft balancer. Tighten: Tighten the bolts to 25 N.m (18 lb ft). Install the J 23523-F forcing screw into the plate. Rotate the J 23523-F forcing screw clockwise in order to remove the crankshaft balancer.
4. Remove the J 23523-F from the crankshaft balancer.
5. Note the position and length of any crankshaft balancer front groove pins, if applicable.

Valve Rocker Arm Cover Removal - Left

1. Remove the valve rocker arm cover bolts.
2. Remove the valve rocker arm cover bolt grommets.
3. Discard the valve rocker arm cover bolt grommets.
4. Remove the valve rocker arm cover.
5. Remove the valve rocker arm cover gasket.
6. Discard the valve rocker arm cover gasket.

Valve Rocker Arm Cover Removal - Right

1. Remove the valve rocker arm cover bolts.
2. Remove the valve rocker arm cover bolt grommets.
3. Discard the valve rocker arm cover bolt grommets.
4. Remove the valve rocker arm cover.
5. Remove the valve rocker arm cover gasket.
6. Discard the valve rocker arm cover gasket.

Distributor Removal

1. Remove the ignition coil wire harness from the ignition coil and distributor cap.
2. Remove the distributor clamp bolt.
3. Remove the distributor and the distributor clamp.
4. Remove the distributor gasket and discard.

Scheme 24

1. Remove the evaporative emission (EVAP) canister purge solenoid valve harness. Push the quick disconnect clip and hold in place. Pull outward on the harness elbow.
2. Remove the engine coolant temperature (ECT) sensor wire connector, if equipped, from the engine wiring harness bracket.
3. Remove the lower intake manifold bolts.
4. Remove the intake manifold assembly.
5. Remove and discard the lower intake manifold gaskets.

Valve Rocker Arm and Push Rod Removal

1. Remove the valve rocker arms.
2. Remove the valve rocker arm supports.
3. Remove the valve pushrods.

Cylinder Head Removal - Left

1. Remove the engine coolant temperature sensor, if applicable.
2. Remove the engine coolant temperature gage sensor, if applicable.
3. Remove the spark plugs.
4. Remove the bolts and the spark plug wire support.
5. Remove the cylinder head bolts and discard.
6. Remove the cylinder head.
7. Remove and discard the cylinder head gasket.
8. Remove the cylinder head locator dowel pins, if required.

Cylinder Head Removal - Right

1. Remove the spark plugs.
2. Remove the rear bolt and the spark plug wire support.
3. Remove the cylinder head bolts and discard.
4. Remove the cylinder head.
5. Remove and discard the cylinder head gasket.
6. Remove the cylinder head locator dowel pins, if required.

Valve Lifter Removal

Tools Required: J 3049-A Valve Lifter Remover. See Special Tools and Equipment .

1. Remove the bolts and valve lifter pushrod guide.
2. Remove the valve lifters.
3. Use the J 3049-A in order to remove the stuck valve lifters. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Oil Filter Adapter Removal

1. Remove the oil filter adapter bolts.
2. Remove the oil filter adapter and the oil filter adapter gasket.
3. Discard the oil filter adapter gasket.
4. Remove the oil filter adapter seal (O-ring).
5. Discard the oil filter adapter seal (O-ring).

Oil Pan Removal

1. Remove the oil pan bolts and nuts.
2. Remove the oil pan.
3. Remove the oil pan gasket.
4. Discard the oil pan gasket.

Oil Pump Removal

1. Remove the oil pump bolt.
2. Remove the oil pump.
3. Inspect the oil pump locator pins for damage, and replace the pins if required.

Engine Front Cover Removal

1. Remove the crankshaft position sensor bolt.
2. Remove the crankshaft position sensor.
3. Remove the crankshaft position sensor seal, O-ring.
4. Discard the crankshaft position sensor seal, O-ring.
5. Remove the engine front cover bolts.
6. Remove the engine front cover.
7. Discard the engine front cover.

Timing Chain and Sprockets Removal

Tools Required: J 5825-A Crankshaft Gear Remover. See Special Tools and Equipment .

Scheme 25

1. Remove the crankshaft position sensor reluctor ring.
2. Remove the timing chain tensioner shoe (229) using a downward motion.
3. Remove the timing chain tensioner bracket bolt and bracket (227 and 228).
4. Check the camshaft timing chain free play. Rotate the camshaft sprocket (1) counterclockwise until all slack is removed from the camshaft timing chain (2). Measure the free play on the slack side (3) of the camshaft timing chain. If the camshaft timing chain can be moved side to side in excess of 11 mm (0.43 in), replacement of the camshaft timing chain and the sprockets is recommended during assembly.
5. Remove the camshaft sprocket bolts.
6. Remove the camshaft sprocket and the camshaft timing chain.
7. Remove the crankshaft sprocket using the J 5825-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
8. Remove the crankshaft balancer key.

Balance Shaft Removal

1. Remove the balance shaft drive gear.
2. Remove the balance shaft driven gear bolt from the balance shaft. Use a wrench in order to secure the balance shaft. Place the wrench onto the balance shaft near to the balance shaft front bearing. Remove the balance shaft bolt. Remove the wrench from the balance shaft.
3. Remove the balance shaft driven gear from the balance shaft.
4. Remove the bolts and the balance shaft retainer.
5. Use a soft-faced hammer in order to remove the balance shaft from the engine block.

Camshaft Removal

1. Remove the camshaft retainer bolts and retainer.
2. Remove the engine camshaft. Install the three 5/16-18 x 4.0 inch bolts into the engine camshaft front bolt holes. Using the bolts as a handle, carefully rotate and pull the engine camshaft out of the camshaft bearings. Remove the bolts from the front of the engine camshaft.

Piston, Connecting Rod, and Bearing Removal

Tools Required

1. J 5239 Connecting Rod Bolt Guide Set. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 24270 Cylinder Bore Ridge Reamer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Scheme 26

1. Use the J 24270 in order to remove the cylinder ring ridge. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Turn the crankshaft until the piston is at the bottom of the stroke. Place a cloth on top of the piston. Use the J 24270 to remove all of the cylinder ring ridge. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Turn the crankshaft so the piston is at the top of the stroke. Remove the cloth. Remove the cutting debris.
2. Remove the connecting rod nuts.
3. Remove the connecting rod cap.
4. Use the J 5239 in order to protect the crankshaft journals and remove the connecting rod and the piston out of the top of the engine block. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Remove the connecting rod bearings. Keep the connecting rod bearings with the original connecting rod and connecting rod cap. Wipe the oil from the connecting rod bearings. Wipe the oil from the crankpins.

Crankshaft Rear Oil Seal and Housing Removal

1. Remove the crankshaft rear oil seal from the crankshaft rear oil seal housing. Insert a suitable tool into the access notches and then carefully pry the crankshaft rear oil seal from the crankshaft rear oil seal housing.
2. Discard the crankshaft rear oil seal.
3. Remove the crankshaft rear oil seal housing nut and bolts.
4. Remove the crankshaft rear oil seal housing.
5. Remove the crankshaft rear oil seal housing gasket.
6. Discard the crankshaft rear oil seal housing gasket.
7. Remove the crankshaft rear oil seal housing retainer stud from the engine block.

Crankshaft and Bearings Removal

1. Mark or identify the crankshaft bearing cap locations, direction, and positions for assembly.
2. Remove the crankshaft bearing cap bolts and discard.
3. Remove the crankshaft bearing caps.
4. Remove the crankshaft.
5. Remove the crankshaft bearings from the crankshaft bearing caps.
6. Remove the crankshaft bearings from the engine block.

Engine Block Plug Removal

Tools Required: J 41712 Oil Pressure Switch Socket. See Special Tools and Equipment .

Scheme 27

1. Remove the knock sensor retaining bolt (1).
2. Remove the knock sensor (2).
3. Remove the engine oil pressure gage sensor using the J 41712 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Remove the engine oil pressure sensor fitting.
5. Remove the transmission locator dowel straight pins, if required.
6. Remove the engine block left side oil gallery plug.
7. Remove the engine block left rear oil gallery plug.
8. Remove the engine block right rear oil gallery plug.
9. Remove the expansion cup plug from the camshaft rear bearing hole and discard.
10. Remove the expansion cup plug from the balance shaft rear bearing hole and discard.
11. Remove the crankshaft rear oil seal housing locator spring type S pin, if required.
12. Remove the front oil gallery plugs or balls from the front of the engine block and discard. Insert a 3/8 x 26 inch rod into the rear oil gallery holes in order to drive out the front oil gallery plugs or balls.
13. Remove the engine block core hole plugs. Use a suitable tool in order to drive the engine block core hole plugs into the coolant jacket. Use a suitable tool in order to pull the engine block core hole plugs from the coolant jacket. Discard the engine block core hole plugs.
14. Remove the oil filter bypass valve and discard.

Engine Block Cleaning and Inspection

Tools Required: J 8087 Cylinder Bore Gage. See Special Tools and Equipment .

Scheme 28

Scheme 29

1. Clean all the remaining sealing or gasket material from the sealing surfaces.
2. Clean the engine block with cleaning solvent.
3. Flush the engine block with clean water or steam.
4. Clean the cylinder bores.
5. Clean the oil galleries and the oil passages.
6. Clean the scale and the deposits from the coolant passages.
7. Clean the engine block cylinder head bolt holes.
8. After cleaning the engine block, spray or wipe the cylinder bores and the machined surfaces with clean engine oil.
9. Inspect the following areas: Coolant jackets (1) for cracks Cylinder bores (2) for scratches or gouging Valve lifter bores (3) for excessive scoring or wear Threaded holes (4) for damage Crankshaft bearing webs (5) for cracks Crankshaft bearing caps (6) and the crankshaft bearing bores (7) for damage The crankshaft bearing bores should be round and uniform when measuring the inside diameter (ID). The surface where the crankshaft bearings contact the crankshaft bearing bore should be smooth. If a crankshaft bearing cap is damaged and requires replacement, replace the crankshaft bearing cap first, then rebore the engine block crankshaft bearing bores and check for the proper alignment. Finally, check the crankshaft for the proper clearances. Engine block core hole plug bores (8) for damage Engine block (9) for cracks or damage Engine mount bosses (10) for damage
10. Measure the cylinder bores for taper and out-of-round. Depress the plunger on the J 8087 to 7 mm (0.275 in) or until the J 8087 enters the cylinder bore. Center the J 8087 in the cylinder bore and turn the indicator dial to 0. Move the J 8087 up and down the cylinder bore to determine the cylinder bore taper. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) . Turn the J 8087 to different points around the cylinder bore to determine the cylinder bore out-of-round condition. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) .

Honing Procedure

1. When honing the cylinder bores, follow the manufacturer's recommendations for equipment use, cleaning, and lubrication. Use only clean sharp stones of the proper grade for the amount of material to be removed. Dull, dirty stones cut unevenly and generate excessive heat. DO NOT hone to a final grade with a coarse or medium-grade stone. Leave sufficient metal so that all the stone marks will be removed with the fine grade stones. Perform the final honing with a fine-grade stone and hone the cylinder bore in a cross hatch pattern at 45-65 degrees to obtain the proper clearance.
2. During the honing operation, thoroughly check the cylinder bore. Repeatedly check the cylinder bore fit with the selected piston. All measurements of the piston or cylinder bore should be made with the components at normal room temperature.
3. When honing to eliminate taper in the cylinder bore, use full strokes the complete length of the cylinder bore. Repeatedly check the measurement at the top, the middle, and the bottom of the cylinder bore. The finish marks should be clean but not sharp. The finish marks should be free from imbedded particles or torn or folded metal.
4. When finished, the reconditioned cylinder bores should have less than or meet the specified out-of-round and taper requirements.
5. After the final honing and before the piston is checked for fit, clean the cylinder bore with hot water and detergent. Scrub the cylinder bores with a stiff bristle brush. Rinse the cylinder bores thoroughly with clean hot water. Dry the cylinder bores with a clean rag. Do not allow any abrasive material to remain in the cylinder bores. Abrasive material may cause premature wear of the new piston rings and the cylinder bores. Abrasive material will contaminate the engine oil and may cause premature wear of the bearings.
6. Perform final measurements of the piston and the cylinder bore.
7. Permanently mark the top of the piston for the specified cylinder to which it has been fitted.
8. Apply clean engine oil to each cylinder bore in order to prevent rusting.

Boring Procedure

1. Before starting the honing or reboring operation, measure all the new pistons with the micrometer contacting at points exactly 90 degrees from the piston pin centerline.
2. File the top of the cylinder block in order to remove any dirt or burrs before using any type of boring bar.
3. Follow the instructions furnished by the manufacturer regarding use of the boring equipment.
4. When reboring the cylinders, make sure all the crankshaft bearing caps are installed in the original position and direction.
5. Tighten the crankshaft bearing caps to the proper torque specifications in order to avoid distortion of the cylinder bores in the final assembly.
6. When making the final cut with the boring bar, leave 0.03 mm (0.001 in) on the cylinder bore diameter for finish honing. This gives the required position to the cylinder clearance specifications. Carefully perform the honing and boring operation in order to maintain the specified clearances between the pistons, the piston rings, and the cylinder bores.

Piston and Connecting Rod Disassemble

Tools Required: J 24086-C Piston Pin Remover/Installer. See Special Tools and Equipment .

1. Remove the piston rings from the pistons.
2. Press the piston pin from the connecting rod using the J 24086-C . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . The piston pin has an interference fit into the connecting rod, and is full floating in the piston.
3. Mark, separate, and organize the parts for assembly.

Scheme 30

Scheme 31

1. Clean the piston and connecting rod in solvent.
2. Dry the components with compressed air.
3. Clean the piston ring grooves with a suitable ring groove cleaning tool.
4. Clean the piston oil lubrication holes and slots.
5. Inspect the piston for the following: Eroded areas (1) on the top of the piston Scuffed or damaged skirt (2) Damage to the pin bore (3) Cracks in the piston ring lands, the piston skirt, or the pin bosses Piston ring grooves for nicks, burrs, or other warpage which may cause the piston ring to bind
6. Inspect the piston pin for scoring, wear or other damage.
7. Measure the piston ring-to-piston ring groove side clearance. Insert the edge of the piston ring into the piston ring groove. Roll the piston ring completely around the piston. If binding is caused by a distorted piston ring groove, MINOR imperfections may be removed with a fine file. If binding is caused by a distorted piston ring, replace the piston ring.
8. Measure the piston ring side clearance with a feeler gauge.
9. If the side clearance is too small, try another piston ring set.
10. If the proper piston ring-to-piston ring groove clearance cannot be achieved, replace the piston and pin assembly.
11. To determine the proper piston ring side clearance, refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) .
12. Inspect the connecting rod for an out-of-round bearing bore. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) .
13. Inspect the connecting rod for twisting.
14. Inspect the connecting rod for damage to the bearing cap and bolt threads.
15. Measure the piston compression ring end gap. IMPORTANT: Fit each compression ring to the cylinder in which it will be used. Place the compression ring into the cylinder bore. Push the compression ring into the cylinder bore to approximately 6.5 mm (0.25 in) above the ring travel. The ring must be square to the cylinder wall. Use a feeler gage in order to measure the end gap. Select another size ring set if the end gap exceeds specifications. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) .

J 24086-C Piston Pin Remover/Installer. See Special Tools and Equipment .

Scheme 32

1. Install the new piston pin and connecting rod assembly. Lubricate the piston pin bores with clean engine oil. Use a torch and apply MILD heat to the piston pin end of the connecting rod. Use the J 24086-C in order to press the new piston pin into the piston and connecting rod assembly. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Inspect for the proper installation of the piston and piston pin. The piston must move freely on the new piston pin with no binding or interference.
2. Install the piston rings onto the piston. Install the oil control piston ring spacer. Install the lower oil control piston ring. Install the upper oil control piston ring. Install the lower compression piston ring. The mark on the side of the piston ring should face the top of the piston. Install the upper compression piston ring. The mark on the side of the piston ring should face the top of the piston.
3. Space the compression piston ring end gaps 120 degrees apart.
4. Space the oil control piston ring end gaps a minimum of 90 degrees apart.

Crankshaft and Bearings Cleaning and Inspection

Tools Required

1. J 7872 Magnetic Base Dial Indicator. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 45059 Angle Meter. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. J 43690 Rod Bearing Clearance Checking Tool. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Scheme 33

Scheme 34

Scheme 35

1. Clean the crankshaft in cleaning solvent. Remove all sludge or restrictions from the oil passages.
2. Dry the crankshaft with compressed air.
3. Clean the crankshaft bearings in cleaning solvent. Wipe the crankshaft bearings clean with a soft cloth, do not scratch the crankshaft bearing surfaces.
4. Dry the crankshaft bearings with compressed air.
5. Inspect the crankshaft for the following: Crankshaft journals (1) should be smooth with no evidence of scoring or damage. Deep grooves (2) Scratches or uneven wear (3) Pitted surfaces (4) Wear or damage to the thrust journal surfaces Scoring or damage to the rear seal surface Restrictions to the oil passages Damage to the threaded bolt holes
6. Inspect the crankshaft balancer key (1), the keyway (2), and the threaded hole (3) for damage. Repair or replace the crankshaft as necessary.
7. Measure the crankpins for out-of-round and taper. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) .
8. Use a suitable support to support the crankshaft on the front and rear journals.
9. Use the J 7872 in order to measure the crankshaft journal runout. The proper crankshaft journal runout is 0.025 mm maximum (0.0010 in maximum).
10. Measure the crankshaft end play. IMPORTANT: In order to properly measure the crankshaft end play, the crankshaft, the crankshaft bearings, the crankshaft bearing caps, and the crankshaft bearing cap bolts must be installed into the engine block and the bolts tightened using J 45059 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . The proper crankshaft bearing cap bolt tightening specification first pass is 20 N.m (15 lb ft), final pass is 73 degrees. Firmly thrust the crankshaft first rearward, then forward. This will align the crankshaft rear bearings and the crankshaft thrust surfaces. With the crankshaft pushed forward, insert a feeler gage between the crankshaft and the crankshaft bearing surface and then measure the clearance. The proper crankshaft end play clearance specification is 0.050-0.20 mm (0.002-0.008 in). Turn the crankshaft to check for binding. If the crankshaft does not turn freely, then loosen the crankshaft bearing cap bolts, one crankshaft bearing cap at a time, until the tight crankshaft bearing is located. Burrs on the crankshaft bearing cap or engine block, foreign matter between the crankshaft bearing and the crankshaft bearing cap or the engine block, or a faulty crankshaft bearing could cause a lack of clearance between the crankshaft and crankshaft bearing.
11. Inspect the crankshaft bearings for craters or pockets. Flattened sections on the crankshaft bearing halves also indicate fatigue.
12. Inspect the crankshaft bearings for excessive scoring or discoloration.
13. Inspect the crankshaft bearings for dirt or debris imbedded into the crankshaft bearing material.
14. Inspect the crankshaft bearings for improper seating indicated by bright, polished sections of the crankshaft bearings. If the lower half of the crankshaft bearing is worn or damaged, both the upper and lower halves of the crankshaft bearing should be replaced. Generally, if the lower half of the crankshaft bearing is suitable for use, the upper half of the crankshaft bearing should also be suitable for use.

Measuring Crankshaft Bearing Clearances

1. The crankshaft bearings are of the precision insert type and do not use shims for adjustment. If the clearances are excessive, then new upper and lower crankshaft bearings will be required. The service crankshaft bearings are available in the standard size and an undersize.
2. The selective fitting of the crankshaft bearings are necessary in production in order to obtain close tolerances. For this reason, in one journal bore you may use one-half of a standard crankshaft bearing with one-half of an undersize crankshaft bearing.
3. In order to determine the correct replacement bearing size, the bearing clearance must be measured accurately. When checking main bearing clearances, either the micrometer or plastic gage method may be used; however, the micrometer method gives more reliable results and is preferred. When checking connecting rod bearing clearances, the plastic gage method will result in unreliable measurements. The use of J 43690 is preferred. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Normally the crankshaft bearing journals wear evenly and are not out-of-round. However, if a crankshaft bearing is being fitted to an out-of-round crankshaft bearing journal, be sure to fit to the maximum diameter of the crankshaft bearing journal. If the crankshaft bearing is fitted to the minimum diameter and the crankshaft bearing journal is excessively out-of-round, the interference between the crankshaft bearing and the crankshaft bearing journal will result in rapid crankshaft bearing failure.
5. If the crankshaft bearing clearance is within specifications, the crankshaft bearing is satisfactory. If the clearance is not within specifications, replace the crankshaft bearing. Always replace both the upper and lower crankshaft bearings as a set.
6. A standard or undersize crankshaft bearing combination may result in the proper clearance. If the proper crankshaft bearing clearance cannot be achieved using the standard or the undersize crankshaft bearings, it may be necessary to repair or replace the crankshaft.

Measuring Crankshaft Bearing Clearances - Micrometer Method

1. Measure the crankshaft journal diameter with a micrometer in several places, approximately 90 degrees apart. Average the measurements.
2. Determine the taper and out-of-round of the journal. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) .
3. Install the bearings into the engine block or connecting rod assembly.
4. Install the bearing cap bolts and tighten to specifications. Refer to «Fastener Tightening Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__fastener-tightening-specifications) .
5. Measure the bearing inside diameter (ID) at two points 90 degrees apart. Average the measurements.
6. In order to determine the bearing clearance, subtract the average journal diameter from the average bearing inside diameter.
7. Compare the readings to specifications. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) .
8. Replace bearing halves as required to obtain the proper bearing clearances.

Measuring Connecting Rod Bearing Clearances - J 43690 Method

1. Remove the oil pan and other necessary components to gain access to the connecting rods. Remove the oil pump, screen, and deflector, when applicable.
2. Rotate the crankshaft until the crankshaft journal/connecting rod to be measured is in the 10 o'clock position.
3. Remove the bearing cap bolts, cap and bearing half.
4. Insert a piece of paper card stock onto the crankshaft journal. Install the bearing half, bearing cap, and bolts. Refer to «Fastener Tightening Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__fastener-tightening-specifications) .
5. Install the foot (1) and bolt (2) to the pivot arm assembly (3). Tighten the bolt until snug.
6. Install the screw (1 or 3) to the pivot arm assembly (2).
7. Install the pivot arm assembly (1) onto the connecting rod.
8. Position the foot of the pivot arm assembly over the large end of the connecting rod bolt.
9. Position the screw (1) onto the small end of the connecting rod bolt and tighten securely.
10. Install the base (1) and bolt (2) to the oil pan rail.
11. Align the center of the base (1) with the screw (3) of the pivot arm assembly. Tighten the bolt (2) until snug.
12. Align the link (1) of the pivot arm assembly on a plane (3) equal to that of the connecting rod beam (2).
13. With the link of the pivot arm assembly aligned to the beam of the connecting rod, position the pivot arm to the base and insert the pin (1).
14. Insert the handle (1) to the pivot arm assembly.
15. Select the adapter (2), as required, and install to the swivel base (1). Tighten until snug.
16. Install the indicator (2) to the swivel base (1). Tighten the clamp of the base until snug.
17. Install the swivel base (1) to the oil pan rail of the engine block. Tighten until snug.
18. Adjust the swivel base as required and position the indicator tip slightly above the connecting rod cap. Lock the swivel base in position by rotating the locking lever (1). Do not allow the tip of the indicator to contact the connecting rod at this time.
19. The tip of the indicator should be positioned above and NOT in contact with the cap end of the connecting rod.
20. Rotate the fine adjustment knobs on the dial indicator end of the swivel base to position the tip of the indicator in contact with the connecting rod.
21. Lightly actuate the handle of the pivot arm assembly, multiple times in both directions, to ensure the oil film is removed from the journal.
22. Load the handle in the forward position and zero the dial indicator. Load the handle multiple times in both directions and record the reading.
23. Remove the bearing cap bolts, cap, and paper stock.
24. Replace bearing halves as required to obtain the proper bearing clearances.
25. Install the bearings, cap, and bolts. Refer to «Fastener Tightening Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__fastener-tightening-specifications) .

Measuring Crankshaft Bearing Clearances - Plastic Gage Method

1. Install the crankshaft bearings into the engine block.
2. Install the crankshaft.
3. Install the gaging plastic the full width of the journal.
4. Install the crankshaft bearings into the crankshaft bearing caps.
5. Install the crankshaft bearing caps in the original positions and with the arrow on the crankshaft bearing caps in the direction of the front of the engine block.
6. Install the crankshaft bearing cap bolts. Tighten: Tighten the crankshaft bearing caps to 105 N.m (77 lb ft).
7. Remove the crankshaft bearing cap bolts.
8. Remove the crankshaft bearing caps. The gaging plastic may adhere to either the crankshaft bearing journal or the crankshaft bearing surface.
9. Without removing the gaging plastic, measure the compressed width at the widest point using the graduated scale on the edge of the gaging plastic envelope. If the flattened gaging plastic tapers toward the middle or the ends, there may be a difference in clearance indicating taper, low spot or other irregularity of the crankshaft bearing or the crankshaft bearing journal.
10. Remove the flattened gaging plastic.
11. Measure the remaining crankshaft bearing journals.

Measuring Connecting Rod Bearing Side Clearance

1. Insert a feeler gage between the connecting rod caps and measure the connecting rod side clearance. The proper connecting rod side clearance specification is 0.15-0.44 mm (0.006-0.017 in).
2. Connecting rod side clearances may also be measured with a dial indicator set.

Scheme 36

1. Clean the crankshaft balancer in cleaning solvent.
2. Dry the crankshaft balancer with compressed air.
3. Inspect the crankshaft balancer for the following: Loose or improperly installed crankshaft balancer front groove pin (1) A properly installed front groove pin should be installed until flush or below flush with the face of the crankshaft balancer. IMPORTANT: A crankshaft front oil sealing surface with excessive scoring, grooves, rust, or other damage must be replaced. Worn, grooved, or damaged crankshaft front oil sealing surface (2) Minor imperfections on the crankshaft balancer crankshaft front oil seal surface may be removed with a polishing compound or fine grade emery cloth. Worn, chunking, or deteriorated rubber (3) between the hub and the outer ring Worn or damaged keyway (4) Worn or damaged bolt hole threads (5)

Scheme 37

Scheme 38

1. Clean the engine flywheel (1 or 2) in cleaning solvent.
2. Dry the engine flywheel with compressed air.
3. Inspect the engine flywheel, automatic transmission, if equipped, for the following: Stress cracks around the engine flywheel-to-torque converter bolt hole locations (1) Missing balance weights Stress cracks around the engine flywheel-to-crankshaft bolt hole locations (2 or 3) Welded areas that retain the ring gear onto the engine flywheel for cracking (4), if present Damaged ring gear teeth (5)
4. Inspect the engine flywheel, manual transmission, if equipped, for loose or improperly installed flywheel weights, if applicable. A properly installed flywheel weight should be installed until flush or below flush with the face of the engine flywheel.
5. Inspect the engine flywheel, manual transmission, if equipped, for the following: Pitted friction surface (1) Scoring or grooves (2) Rust or other surface damage (3) Damaged ring gear teeth (4) Loose or improperly positioned ring gear The ring gear has an interference fit onto the engine flywheel and the ring gear should be positioned completely flat against the flange of the engine flywheel.

Camshaft and Bearings Cleaning and Inspection

Tools Required: J 7872 Magnetic Base Dial Indicator. See Special Tools and Equipment .

Scheme 39

Scheme 40

1. Clean the engine camshaft in cleaning solvent.
2. Dry the engine camshaft with compressed air.
3. Inspect the camshaft retainer plate for damage. If the camshaft retainer plate is damaged, replace as necessary.
4. Inspect the camshaft bearings for correct fit into the engine block camshaft bearing bores. The camshaft bearings have an interference fit to the engine block camshaft bearing bores and must not be loose in the engine block camshaft bearing bores.
5. Inspect the camshaft bearings for excessive wear or scoring.
6. Inspect the engine camshaft for the following: Worn, scored, or damaged bearing journals (1) Worn engine camshaft lobes (2) Damaged bolt hole threads (3) Damaged camshaft sprocket locator pin (4)
7. Measure the engine camshaft journals with a micrometer. If the camshaft journals are more than 0.025 mm (0.0010 in) out-of-round, then replace the engine camshaft.
8. Measure for a bent engine camshaft or excessive engine camshaft runout using the J 7872 . Mount the engine camshaft in a suitable stand between centers. Use the J 7872 in order to check the intermediate engine camshaft journals. If the runout exceeds 0.065 mm (0.0026 in), the engine camshaft is bent and must be replaced.
9. Measure the engine camshaft lobe lift using the J 7872 . Place the engine camshaft on the V-blocks. Use the J 7872 in order to measure the engine camshaft lobe lift.
10. Replace the engine camshaft if the engine camshaft lobe lift is not within specifications. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) .

Camshaft Bearing Removal

Tools Required: J 33049 Camshaft Bearing Service Kit. See Special Tools and Equipment .

Scheme 41

1. Select the cone (1), the handle (10), the expanding driver (4-8), the washer (2 or 3), and the expander assembly (15) from the J 33049 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Assemble the J 33049 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Remove the camshaft inner bearings #2 and #3. Insert the J 33049 through the front of the engine block and into the camshaft inner bearing #2. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten the J 33049 expander assembly nut until snug. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Push the J 33049 guide cone into the camshaft front bearing in order to align the J 33049 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Drive the camshaft inner bearing #2 from the camshaft inner bearing bore #2. Loosen the J 33049 expander assembly nut. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Remove the camshaft inner bearing #2 from the J 33049 expander assembly. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Insert the J 33049 expander assembly into the camshaft inner bearing #3. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten the J 33049 expander assembly nut until snug. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Push the J 33049 guide cone into the camshaft front bearing in order to align the J 33049 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Drive the camshaft inner bearing #3 from the camshaft inner bearing bore #3. Loosen the J 33049 expander assembly nut. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Remove the camshaft inner bearing #3 from the J 33049 expander assembly. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Remove the J 33049 from the engine block. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Remove the camshaft outer bearings #1 and #4. Insert the J 33049 into the camshaft outer bearing #1. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten the J 33049 expander assembly nut until snug. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Drive the camshaft outer bearing #1 from the camshaft outer bearing bore #1. Loosen the J 33049 expander assembly nut. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Remove the camshaft outer bearing #1 from the J 33049 expander assembly. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Remove the J 33049 from the engine block. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Insert the J 33049 into the camshaft outer bearing #4. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten the J 33049 expander assembly nut until snug. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Drive the camshaft outer bearing #4 from the camshaft outer bearing bore #4. Loosen the J 33049 expander assembly nut. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Remove the camshaft outer bearing #4 from the J 33049 expander assembly. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
6. Remove the J 33049 from the engine block. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
7. Discard the camshaft bearings.

Camshaft Bearing Installation

Tools Required: J 33049 Camshaft Bearing Service Kit. See Special Tools and Equipment .

Scheme 42

1. Assemble the J 33049 handle (10), the expanding driver (4-8), the washer (2 or 3), and the expander assembly (15). See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Install the NEW camshaft outer bearings #4 and #1. Install the NEW camshaft outer bearing #4 onto the J 33049 expander assembly. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten the J 33049 expander assembly nut until snug. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Align the lubrication hole of the camshaft outer bearing #4 above the 3 o'clock position or the 9 o'clock position of the camshaft outer bearing bore #4 at the rear of the engine block. Drive the camshaft outer bearing #4 into the camshaft outer bearing bore #4 at the rear of the engine block. Loosen the J 33049 expander assembly nut. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Remove the camshaft outer bearing #4 from the J 33049 expander assembly. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install the NEW camshaft outer bearing #1 onto the J 33049 expander assembly. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten the J 33049 expander assembly nut until snug. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Align the lubrication hole of the camshaft outer bearing #1 above the 3 o'clock position or the 9 o'clock position of the camshaft outer bearing bore #1 at the front of the engine block. Drive the camshaft outer bearing #1 into the camshaft outer bearing bore #1 at the front of the engine block. Loosen the J 33049 expander assembly nut. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Carefully slide the J 33049 into the engine block until the J 33049 expander assembly is positioned between the camshaft inner bearing bores. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Install the NEW camshaft inner bearings #3 and #2. Install the NEW camshaft inner bearing #3 onto the J 33049 expander assembly. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten the J 33049 expander assembly nut until snug. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Align the lubrication hole of the camshaft inner bearing #3 above the 3 o'clock position or the 9 o'clock position of the camshaft inner bearing bore #3 of the engine block. Push the J 33049 guide cone into the camshaft front bearing bore #1 in order to align the J 33049 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Drive the camshaft inner bearing #3 into the camshaft inner bearing bore #3. Loosen the J 33049 expander assembly nut. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Carefully slide the J 33049 until the J 33049 expander assembly is positioned between the camshaft inner bearing bore #2 and the camshaft outer bearing bore #1. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install the NEW camshaft inner bearing #2 onto the J 33049 expander assembly. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten the J 33049 expander assembly nut until snug. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Align the lubrication hole of the camshaft inner bearing #2 above the 3 o'clock position or the 9 o'clock position of the camshaft inner bearing bore #2 of the engine block. Push the J 33049 guide cone into the camshaft front bearing bore #1 in order to align the J 33049 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Drive the camshaft inner bearing #2 into the camshaft inner bearing bore #2. Loosen the J 33049 expander assembly nut. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Carefully remove the J 33049 from the engine block. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Balance Shaft Bearing and/or Bushing Removal

Tools Required

1. J 26941 Bushing/Bearing Remover. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 38834 Balance Shaft Service Kit. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Use the J 38834 and the J 26941 in order to remove the balance shaft rear bearing. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install J 26941 legs behind the balance shaft rear bearing and secure. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install the J 38834-1 with the short threaded end through the balance shaft bore in the front of the engine block. Install the J 38834-1 into J 26941 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Slide the J 38834-2 onto the J 38834-1 and into the balance shaft bore of the engine block. Install the J 38834 bearing, washer, and nut onto the J 38834-1. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Using a wrench secure the J 38834-1 and then rotate the J 38834 nut clockwise until the balance shaft rear bearing is removed from the engine block. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Remove the J 26941 from the balance shaft rear bearing. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Discard the balance shaft rear bearing.

Scheme 43

Scheme 44

1. Clean the following components in cleaning solvent: The balance shaft (1) The balance shaft retainer (2) The balance shaft rear bearing (3) The balance shaft driven gear (4) The balance shaft drive gear (5)
2. Dry the following components with compressed air: The balance shaft (1) The balance shaft retainer (2) The balance shaft rear bearing The balance shaft driven gear (4) The balance shaft drive gear
3. Inspect the balance shaft bearings for the following: Front ball bearing for damage or wear Front ball bearing for smoothness of operation Rear sleeve bearing for wear, scoring, or other damage
4. Inspect the balance shaft (1) for the following: Wear or scoring on the rear bearing journal Damaged bolt hole threads Damage to the balance shaft driven gear locator pin
5. Inspect the balance shaft retainer (2) for wear or damage.
6. Inspect the balance shaft retainer bolts (3) for damaged threads.
7. Inspect the driven gear (4) for the following: Excessive wear or damage Nicks, burrs, or scoring
8. Inspect the driven gear bolt (5) for damaged threads.
9. Inspect the balance shaft drive gear for the following: Excessive wear or damage Nicks, burrs, or scoring

Balance Shaft Bearing and/or Bushing Installation

Tools Required: J 38834 Balance Shaft Service Kit. See Special Tools and Equipment .

1. Use the J 38834 in order to install the balance shaft rear bearing. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install the J 38834-3 onto the short threaded end of the J 38834-1. Install the J 38834 nut, the washer, and the bearing on the long threaded end of the J 38834-1. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Install the J 38834-2 onto the J 38834-1 so that the smaller diameter of the J 38834-2 will be facing the front of the engine block. Install the J 38834-2 on the inside of the balance shaft front bearing bore. Lubricate the NEW balance shaft rear bearing with clean engine oil. Install the balance shaft rear bearing onto the J 38834-2. Align the balance shaft rear bearing for installation. Using a wrench secure the J 38834-1 into place. Rotate the J 38834 nut until the balance shaft rear bearing is properly and completely pushed into the balance shaft rear bearing bore. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the J 38834 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Scheme 45

1. Clean the components with cleaning solvent.
2. Dry the components with compressed air.
3. Inspect the camshaft timing chain for binding or wear.
4. Inspect the camshaft sprocket and the crankshaft sprocket for: Broken teeth (1) Damaged teeth (2) Chipped teeth (3) Worn teeth Uneven wear on the edge of the teeth Worn valleys between the sprocket teeth Crankshaft sprocket keyway for wear
5. Inspect the timing chain tensioner bracket and shoe for cracking and wear.

Scheme 46

1. Mark, sort, and organize the components for assembly.
2. Clean the components with cleaning solvent.
3. Dry the components with compressed air.
4. Inspect the valve rocker arm components for the following: Valve rocker arm valve pushrod socket contact surface (1) The contact surface must be smooth with no scoring or excessive wear. Valve rocker arm roller pivot for binding or damage (2) Valve rocker arm valve stem contact surface (3) The contact surface should be smooth with no scoring or excessive wear. Valve rocker arm bolt threads for damage (4)
5. Inspect the valve pushrods for the following: Restriction of the oil passage (1) Wear or scoring of the end contact surfaces (2) The end contact surfaces must be smooth with no scoring or excessive wear. Shaft for bends (3) Roll the valve pushrod on a flat surface to determine if the valve pushrod is bent.
6. Inspect the valve rocker support for excessive wear or damage.

Scheme 47

1. Mark, sort, and organize the components for assembly.
2. Clean the components in cleaning solvent.
3. Dry the components with compressed air.
4. Inspect the valve lifter pushrod guides for excessive wear.
5. Inspect the valve lifter pushrod guides for cracks or damage.
6. Inspect the valve lifter for the following: Broken or damaged clip (1) Worn pushrod socket (2) Scuffed or worn lifter body (3) If the valve lifter shows scuffing or wear, inspect the engine block valve lifter bores for wear. Worn roller (4) Loose or damaged pin (5) Plugged oil hole (6)

Cylinder Head Disassemble

Tools Required: J 8062 Valve Spring Compressor. See Special Tools and Equipment .

1. Use the J 8062 in order to compress the valve springs. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. Remove the valve stem keys (1).
3. Remove the J 8062 from the cylinder head. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Remove the valve spring cap (2).
5. Remove the valve spring (3).
6. Remove the valve stem oil seal (4).
7. Discard the valve stem oil seal.
8. Remove the valve.

Cylinder Head Cleaning and Inspection

Tools Required

1. J 8001 Dial Indicator Set. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 8089 Carbon Removing Brush
3. J 9666 Valve Spring Tester

Scheme 48

Scheme 49

Scheme 50

1. Clean the valve stems and cylinder heads on a buffing wheel.
2. Clean the following components in cleaning solvent: Valve stem keys (1) Valve spring cap (2) Valve spring (3) Cylinder head
3. Dry the components with compressed air.
4. Use the J 8089 to clean the carbon from the cylinder head combustion chambers. Be careful not to scuff the combustion chambers.
5. Inspect the cylinder head for the following: Damage to the gasket surfaces Damage to the threaded bolt holes Burnt or eroded areas in the combustion chamber Cracks in the exhaust ports and combustion chambers External cracks in the water chamber Restrictions in the intake or exhaust passages Restrictions in the cooling system passages Rusted, damaged, or leaking core plugs
6. Measure the cylinder head for warpage with a straight edge and feeler gage. A cylinder head block deck with warpage in excess of 0.10 mm (0.004 in) within a 152.4 mm (6.0 in) area must be repaired or replaced. A cylinder head exhaust manifold deck with warpage in excess of 0.05 mm (0.002 in) within a 152.4 mm (6.0 in) area must be repaired or replaced. A cylinder head intake manifold deck with warpage in excess of 0.10 mm (0.004 in) within a 152.4 mm (6.0 in) area must be repaired or replaced.
7. Use the J 9666 in order to measure the valve spring. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Replace the valve spring if the valve spring tension is less than 338 N (76 lb) at 43.2 mm (1.70 in).
8. Inspect the valve springs for squareness.
9. Valve stems (1) with excessive valve guide (2) clearance must be repaired or the cylinder head replaced.
10. Measure the valve stem-to-guide clearance. Excessive valve stem-to-guide clearance may cause an excessive oil consumption and may also cause a valve to break. Insufficient clearance will result in noisy and sticky functioning of the valve and will disturb the engine assembly smoothness. Clamp the J 8001 on the exhaust port side of the cylinder head. Position the dial indicator so that the movement of the valve stem from side to side, crosswise to the cylinder head, will cause a direct movement of the dial indicator stem. The dial indicator stem must contract the side of the valve stem just above the valve guide. Drop the valve head about 1.6 mm (0.063 in) off the valve seat. Use light pressure and move the valve stem from side to side in order to obtain a valve stem-to-guide clearance reading. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) .

J 5830-02 Valve Guide Reamer Set. See Special Tools and Equipment .

Scheme 51

Scheme 52

1. Measure the valve stem-to-guide clearance. Refer to «Cylinder Head Cleaning and Inspection»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__cylinder-head-cleaning-and-inspection) .
2. Improper valve stem (1) to valve guide (2) clearance may cause excessive oil consumption.
3. Use the J 5830-3 in order to ream the exhaust valve guide in order to achieve the correct valve stem-to-guide clearance.
4. Always recondition the exhaust valve seat after reaming the exhaust valve guide bores and installing new exhaust valves.
5. Inspect the valves for the following: Burnt or damaged areas (1) Undersized margin (2) Bent stem (3) Scoring or other damage to the stem (4) Worn key groove (5) Worn stem tip (6)
6. Inspect the valve contact surface for the following: Undersized margin (1) Pitted surface (2) Burnt or eroded areas (3) Acceptable edge margin (4) Valves with excessive damage must be replaced. Minor imperfections of the valve or valve seat may be repaired.
7. Reconditioning of the valves and valve seats: The valves must seat perfectly for the engine to deliver optimum power and performance. Cooling the valve heads is another important factor. Good contact between each valve and valve seat in the cylinder head is necessary to insure that the heat in the valve head is properly carried away. Regardless of what type of equipment is used, it is essential that the valve guide bores are free from carbon or dirt in order to ensure the proper centering of the pilot in the valve guide. The valve seats should be concentric to within 0.05 mm (0.002 in) total indicator reading. Reface pitted valves on a valve refacing machine in order to ensure the correct relationship between the valve head and the valve stem. Replace the valve if the valve stem is excessively worn or warped. Replace the valve if the edge margin (4) of the valve head is less than 0.79 mm (0.031 in) thick after grinding. Several different types of equipment are available for reconditioning valves and valve seats. Follow the equipment manufacturer's recommendations for equipment use to attain the proper results.

Cylinder Head Assemble

Tools Required

1. J 8062 Valve Spring Compressor. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 42073 Valve Stem Seal Installer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Assemble the valve into the proper valve guide.
2. Select the proper valve stem oil seal for the specific valve guide.
3. Lubricate the valve stem oil seal and the outside diameter of the valve guide with clean engine oil.
4. Assemble the valve stem oil seal onto the valve stem.
5. Using the J 42073 , install the valve stem oil seal onto the valve guide. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tap the valve stem oil seal onto the valve guide until the J 42073 bottoms against the valve spring seat. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Inspect the valve stem oil seal. The valve stem oil seal should not be bottomed against the valve guide. There should be a 1-2 mm (0.03937-0.07874 in) gap between the bottom edge of the valve stem oil seal and the valve guide.
6. Install the valve spring (3).
7. Install the valve spring cap (2) onto the valve spring (3), over the valve stem.
8. Use the J 8062 to compress the valve spring. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
9. Install the valve stem O-ring seal.
10. Install the valve stem keys. Use grease to hold the valve stem keys in place while disconnecting the J 8062 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tap the end of the valve stem with a plastic-faced hammer to seat the valve stem keys. Inspect the valve stem keys to ensure that they are seated in the upper groove of the valve stem.

Scheme 53

1. Remove the oil pump driveshaft and oil pump driveshaft retainer.
2. Remove the oil pump pipe, if necessary. The oil pump pipe has a press fit into the oil pump cover.
3. Remove the oil pump cover bolts.
4. Remove the oil pump cover.
5. Remove the oil pump drive gear and the oil pump driven gear.
6. Matchmark the gear teeth for assembly.
7. Remove the following items: The oil pump pressure relief valve spring straight pin The oil pump pressure relief spring The oil pump pressure relief valve

Oil Pump Cleaning and Inspection

1. Clean the oil pump components in cleaning solvent.
2. Dry the components with compressed air.
3. Inspect the oil pump for the following conditions: Scoring on the top of the gears (1) Damaged gears (2) for the following: Chipping Galling Wear Scoring, damage or casting imperfections to the body (3) Damaged or scored gear shaft (4) Damaged or scored gear shaft (5) Damaged bolt hole threads Worn oil pump driveshaft bore Damaged or sticking oil pump pressure relief valve Minor imperfections may be removed with a fine oil stone. Collapsed or broken oil pump pressure relief valve spring
4. If the oil pump is to be reused, install a NEW oil pump pressure relief valve spring.
5. During oil pump installation, install a NEW oil pump driveshaft retainer.

Oil Pump Assemble

Tools Required: J 21882 Oil Suction Pipe Installer. See Special Tools and Equipment .

Scheme 54

1. Apply clean engine oil GM P/N 12345610 (Canadian P/N 9931930) or equivalent, to the oil pump pressure relief valve, oil pump pressure relief valve spring, and oil pump body.
2. Install the following items: The oil pump pressure relief valve The oil pump pressure relief valve spring The oil pump pressure relief valve spring straight pin
3. Apply clean engine oil GM P/N 12345610 (Canadian P/N 993193) or equivalent, to the oil pump drive gear, the oil pump driven gear, and the oil pump body internal surfaces.
4. Install the oil pump drive gear and the oil pump driven gear into the oil pump body. Align the matchmarks on the oil pump drive and driven gears. Install the smooth side of the oil pump drive and driven gears toward the oil pump cover.
5. Install the oil pump cover.
6. Install the oil pump cover bolts. Tighten: Tighten the bolts to 12 N.m (106 lb in).
7. Inspect the oil pump for smoothness of operation by turning the oil pump driveshaft by hand.
8. Install the oil pump screen. If removed, replace the oil pump screen. The oil pump screen must have a good press fit into the oil pump body. Mount the oil pump in a soft jawed vise. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the end of the oil pump screen pipe. Use the J 21882 and a soft-faced hammer in order to tap the oil pump screen into the pump body. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . The oil pump screen must align parallel with the bottom of the oil pan when the oil pan is installed.
9. Install the oil pump driveshaft and the NEW oil pump driveshaft retainer.

Scheme 55

1. Clean the valve rocker arm cover in cleaning solvent.
2. Dry the valve rocker arm cover with compressed air.
3. Inspect the valve rocker arm cover for the following: Damage to the PCV valve grommet (1) Damage to the bolt holes (2) A damaged valve rocker arm cover may interfere with the valve rocker arms. Damage to the exterior of the valve rocker arm cover (3) Gouges or damage to the sealing surface (4) Damage to the oil fill tube grommet (5) Restrictions to the ventilation system passages

Scheme 56

1. Remove the oil pan baffle bolts and the oil pan baffle.
2. Clean the oil pan and oil pan baffle in cleaning solvent.
3. Dry the oil pan and oil pan baffle with compressed air.
4. Inspect the oil pan for the following: Gouges or damage to the oil pan sealing surfaces (1) Damage to the threaded holes (2) Damaged oil pan drain hole threads (3) Damage to the oil pan baffle Damage to the exterior of the oil pan A damaged oil pan may interfere with the proper position of the oil pump screen, or may not distribute oil properly in the oil pan sump area.
5. Install the oil pan baffle and the bolts. Tighten: Tighten the oil pan baffle bolts to 12 N.m (106 lb in).

Intake Manifold Disassemble (LU3)

1. Remove the nuts, the studs, and the accelerator control cable bracket.
2. Remove the throttle body attaching studs.
3. Remove the throttle body.
4. Remove the throttle body to upper intake manifold gasket.
5. Discard the throttle body to upper intake manifold gasket.
6. Remove the water outlet studs.
7. Remove the water outlet (1 or 2).
8. Remove the engine coolant thermostat.
9. Remove the engine coolant temperature (ECT) sensor plug (1) or the ECT sensor (2) from the front of the lower intake manifold, if equipped.
10. Remove the studs and the ignition coil.
11. Remove the manifold absolute pressure (MAP) sensor.
12. Remove the MAP sensor seal from the MAP sensor.
13. Discard the MAP sensor seal.
14. Remove the fuel pipe bolt (4).
15. Remove the fuel pipe retainer nuts (1).
16. Remove the fuel pipe retainer (2).
17. Remove the fuel pipe (3).
18. Remove and discard the fuel seal retainers (5).
19. Remove and discard the fuel seals (6), yellow O-rings.
20. Remove and discard the spacer rings (7), flat washers.
21. Remove and discard the fuel seals (8), black O-rings.
22. Remove the studs and the evaporative emission (EVAP) canister purge solenoid valve.
23. Remove the nut and the engine wiring harness bracket.
24. Remove the upper intake manifold attaching studs.
25. Remove the upper intake manifold.
26. Remove the upper intake manifold to lower intake manifold gasket.
27. Discard the upper intake manifold to lower intake manifold gasket.
28. Remove the fuel meter body seal and discard.
29. Remove the 6 injectors from the lower intake manifold bores.
30. Remove the fuel meter body.
31. Remove the bolt and the fuel meter body bracket.

Scheme 57

Scheme 58

1. Clean the upper intake manifold in cleaning solvent.
2. Dry the upper intake manifold with compressed air.
3. Clean the lower intake manifold in cleaning solvent.
4. Dry the lower intake manifold with compressed air.
5. Inspect the upper intake manifold for the following: Cracks or other damage to the exterior (1) Cracking or damage in the gasket grooves (2) and (3) Damage to the throttle body mounting surface (4) Loose or damaged bolt hole thread inserts (5)
6. Inspect the lower intake manifold for the following: Damage to the gasket sealing surfaces (1) and (2) Restricted cooling system passages (3) Cracks or damage Damage to the threaded bolt holes

Scheme 59

1. If reusing the fastener, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the fuel meter body bracket bolt.
2. Install the fuel meter body bracket and bolt. Tighten: Tighten the fuel meter bracket bolt to 10 N.m (89 lb in).
3. Install the fuel meter body into the fuel meter body bracket.
4. Install the 6 injectors into the proper lower intake manifold bores in proper sequence (3, 5, 1, 2, 4, 6).
5. Inspect the injectors in order to ensure that they are firmly seated and locked in the lower intake manifold bores.
6. Ensure that the electrical connections of the injectors are positioned so that they do not interfere with each other, and are pointing towards the center of the intake manifold. Rotate the electrical connector inboard if necessary. Also, ensure there is no tension on the injector wires.
7. Install a NEW upper intake manifold to lower intake manifold gasket into the groove of the upper intake manifold.
8. Install the upper intake manifold onto the lower intake manifold.
9. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the upper intake manifold attaching studs.
10. Install the upper intake manifold attaching studs. Tighten: Tighten the upper intake manifold attaching studs on the first pass to 5 N.m (44 lb in). Tighten the upper intake manifold attaching studs on the final pass to 9 N.m (80 lb in).
11. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the evaporative emission (EVAP) canister purge solenoid valve studs.
12. Install the EVAP canister purge solenoid valve and studs. Tighten: Tighten the EVAP canister purge solenoid valve studs to 10 N.m (89 lb in).
13. Install the engine wiring harness bracket and nut. Tighten: Tighten the engine wiring harness bracket nut to 12 N.m (106 lb in).
14. Install the NEW fuel seals (8), black O-rings, into the fuel meter body.
15. Install the NEW spacer rings (7), flat washers, into the fuel meter body.
16. Install the NEW fuel seals (6), yellow O-rings, into the fuel meter body.
17. Install the NEW fuel seal retainers (5) into the fuel meter body.
18. Install the fuel pipe (3) into the fuel meter body.
19. Install the fuel pipe retainer bracket (2) onto the fuel pipe.
20. Install the fuel pipe retainer bracket nuts (1).
21. If reusing the fastener, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the fuel pipe bolt.
22. Install the fuel pipe bolt (4). Tighten: Tighten the fuel pipe bracket nuts to 3 N.m (27 lb in). Tighten the fuel pipe bolt to 6 N.m (53 lb in).
23. Install a NEW manifold absolute pressure (MAP) sensor seal onto the MAP sensor.
24. Apply a small amount, approximately 1 drop, of clean engine oil to the MAP sensor seal.
25. Install the MAP sensor into the upper intake manifold.
26. Install the ignition coil and studs. Tighten: Tighten the ignition coil studs to 12 N.m (106 lb in).
27. If reusing the engine coolant temperature (ECT) sensor plug (1) or the ECT sensor (2), if equipped, apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the ECT sensor plug (1) or the ECT sensor (2).
28. Install the ECT sensor or plug, if equipped, into the front of the lower intake manifold. Tighten: Tighten the ECT sensor or plug to 20 N.m (15 lb ft).
29. Install the engine coolant thermostat.
30. Install the water outlet (1 or 2).
31. Install the water outlet studs. Tighten: Tighten the water outlet studs to 25 N.m (18 lb ft).
32. Install a NEW throttle body gasket into the groove in the upper intake manifold.
33. Install the throttle body onto the upper intake manifold.
34. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the throttle body attaching studs.
35. Install the throttle body attaching studs. Tighten: Tighten the throttle body attaching studs to 9 N.m (80 lb in).
36. Install the accelerator control cable bracket, the studs, and the nuts. Tighten: Tighten the accelerator control cable bracket stud to the intake manifold to 6 N.m (53 lb in). Tighten the accelerator control cable bracket nuts to 12 N.m (106 lb in). Tighten the accelerator control cable bracket stud to the throttle body to 12 N.m (106 lb in).

Scheme 60

1. Clean the exhaust manifolds in cleaning solvent.
2. Dry the components with compressed air.
3. Inspect the exhaust manifolds for the following: Damage to the gasket sealing surfaces (1) Damage to the threaded holes (2) Restrictions within exhaust passages Broken or damaged exhaust manifold heat shields (3), if applicable Broken or damaged exhaust manifold
4. Measure the alignment or surface flatness of the exhaust manifold flanges using a straight edge and a feeler gage. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) . If the surface flatness is not within the specifications, the exhaust manifold is warped and must be replaced.

Scheme 61

1. Remove the old gasket material from the water pump sealing surfaces.
2. Clean all the dirt and any debris from the water pump.
3. Inspect the water pump for the following: Leakage or damage to the housing cover or gasket (1) Excessive scratches or gouging to the gasket sealing surfaces (2) Leakage from the water pump vent hole (3) A stain around the vent hole is acceptable. If leakage occurred (dripping) with the engine operating and the cooling system pressurized, then replace the water pump. Damaged bolt hole threads (4) Excessive side-to-side movement of the water pump shaft (5) Leakage around the water inlet pipe (6) Leakage around the heater hose pipe (7) Restrictions within the internal coolant passages

Thread Repair

General purpose thread repair kits are available commercially.

1. Determine the size, the pitch, and the depth of the damaged thread.
2. Adjust the stop collars on the cutting tool as needed. Tap the stop collars to the required depth.
3. Drill out the damaged thread.
4. Remove the chips.
5. Apply clean engine oil to the top thread.
6. Use the tap in order to cut new thread.
7. Clean the thread.
8. Screw the thread insert onto the mandrel of the thread insert installer. Engage the tang of the thread insert onto the end of the mandrel.
9. Lubricate the thread insert with clean engine oil - except when installing in aluminum - and install the thread insert.
10. If the tang of the thread insert does not break off when backing out the thread insert installer, break off the tang using a drift punch.

Service Prior to Assembly

1. Dirt will cause premature wear of the rebuilt engine. Clean all the components.
2. Use the proper tools to measure the components when checking for excessive wear. Components not within the manufacturer's specification must be repaired or replaced.
3. When the components are re-installed into an engine, return the components to the original location, position, and direction.
4. During assembly, lubricate all the moving parts with clean engine oil, unless otherwise specified. The engine oil will provide the initial lubrication when the engine is first started.

Engine Prelubing

Tools Required: J 45299 Engine Preluber. See Special Tools and Equipment .

1. Remove the engine oil filter and fill with clean engine oil.
2. Install the oil filter. Tighten: Tighten the oil filter to 30 N.m (22 lb ft).
3. Locate the engine block left oil gallery plug and remove.
4. Install the M16 x 1.5 adapter P/N 509375.
5. Install the flexible hose to the adapter and open the valve.
6. Pump the handle on the J 45299 in order to flow a minimum of 1-1. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .9 liters (1-2 quarts) engine oil. Observe the flow of engine oil through the flexible hose and into the engine assembly.
7. Close the valve and remove the flexible hose and adapter from the engine.
8. Install the gallery plug to the engine. Tighten: Tighten the oil gallery plug to 60 N.m (44 lb ft).
9. Top-off the engine oil to the proper level.

Engine Block Plug Installation

Tools Required: J 41712 Oil Pressure Switch Socket. See Special Tools and Equipment .

1. Install a NEW oil filter bypass valve. Install the oil filter bypass valve into the oil gallery bore until slightly below flush with the surface of the engine block. Using a pointed punch, stake the engine block area around the oil filter bypass valve. Stake in 3 locations 120 degrees apart.
2. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the outside diameter of the NEW front engine oil gallery plugs.
3. Install the NEW front engine block oil gallery plugs. A properly installed front engine oil gallery plug must be installed slightly below flush with the front face of the engine block.
4. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the outside diameter of the NEW engine block core hole plugs.
5. Install the NEW engine block core hole plugs. A properly installed engine block core hole plug must be installed flush or below the bottom of the chamfer (1) of the engine block core hole.
6. Install the crankshaft rear oil seal housing locator spring type S pin, if required.
7. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the outside diameter of the NEW expansion cup plug.
8. Install the NEW expansion cup plug into the balance shaft rear bearing hole.
9. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the outside diameter of the NEW expansion cup plug.
10. Install the NEW expansion cup plug into the camshaft rear bearing hole.
11. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the engine block right rear oil gallery plug, the engine block left rear oil gallery plug, and the engine block left side oil gallery plug.
12. Install the engine block right rear oil gallery plug, the engine block left rear oil gallery plug, and the engine block left side oil gallery plug. Tighten: Tighten the engine block left side oil gallery plug and the engine block right rear oil gallery plug to 20 N.m (15 lb ft). Tighten the engine block left rear oil gallery plug to 30 N.m (22 lb ft).
13. Install the transmission locator dowel straight pins, if required.
14. Install the left side cylinder head locator dowel pins, if required. The installation height should be 6.3-6.5 mm (0.248-0.256 in) (a).
15. Install the right side cylinder head locator dowel pins, if required. The installation height should be 6.3-6.5 mm (0.248-0.256 in) (a).
16. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the engine block coolant drain hole plugs.
17. Install the engine block coolant drain hole plugs. Tighten: Tighten the engine block coolant hole plugs to 20 N.m (15 lb ft).
18. If reusing the engine oil pressure sensor fitting, apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the engine oil pressure sensor fitting.
19. Install the engine oil pressure sensor fitting. Tighten: Tighten the engine oil pressure sensor fitting to 15 N.m (11 lb ft).
20. Rotate the engine oil pressure sensor fitting clockwise to the proper position (1), 50 degrees from the centerline (2).
21. If reusing the engine oil pressure gage sensor, apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the engine oil pressure gage sensor.
22. Install the engine oil pressure gage sensor using the J 41712 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten: Tighten the engine oil pressure gage sensor to 30 N.m (22 lb ft).
23. Install the knock sensor (2).
24. Install the knock sensor retaining bolt (1). Tighten: Tighten the knock sensor to 25 N.m (18 lb ft).

Crankshaft and Bearings Installation

Tools Required: J 45059 Angle Meter. See Special Tools and Equipment .

1. Install the crankshaft bearings into the engine block.
2. Apply clean engine oil to the crankshaft bearings.
3. Apply clean engine oil to the crankshaft bearing journals.
4. Install the crankshaft.
5. Install the crankshaft bearings into the crankshaft bearing caps.
6. Apply clean engine oil to the crankshaft bearings.
7. Install the crankshaft bearing caps in the original position and with the arrow on the crankshaft bearing caps in the direction of the front of the engine block.
8. Install the NEW crankshaft bearing cap bolts until snug.
9. Thrust the crankshaft rearward in order to set and align the crankshaft thrust bearings and the crankshaft bearing caps.
10. Thrust the crankshaft forward in order to align the rear faces of the crankshaft thrust bearings.
11. Tighten the crankshaft bearing cap bolts. Tighten: Tighten the crankshaft bearing cap bolts on the first pass to 20 N.m (15 lb ft). Tighten the crankshaft bearing cap bolts on the final pass an additional 73 degrees using the J 45059 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
12. Measure the crankshaft end play. Firmly thrust the crankshaft rearward, and then forward. This will align the crankshaft rear bearing thrust surfaces. With the crankshaft pushed forward, insert a feeler gage between the crankshaft and the crankshaft rear bearing thrust surface to measure the clearance. Specification: Crankshaft end play 0.05-0.20 mm (0.002-0.008 in)
13. Rotate the crankshaft in order to check for binding. A bent crankshaft or lack of proper crankshaft bearing clearance may cause binding.
14. If the crankshaft does not turn freely, loosen the crankshaft bearing cap bolts on 1 crankshaft bearing cap at a time in order to determine the location of the binding. A lack of proper crankshaft bearing clearance may be caused by the following: Burrs on the crankshaft bearing cap Foreign material between the crankshaft bearing and the engine block Foreign material between the crankshaft bearing and the crankshaft bearing cap Damaged crankshaft bearing Improper size crankshaft bearing

Crankshaft Rear Oil Seal and Housing Installation

Tools Required: J 35621-B Rear Main Seal Installer. See Special Tools and Equipment .

1. Install the crankshaft rear oil seal housing retainer stud. Tighten: Tighten the crankshaft rear oil seal housing retainer stud to 6 N.m (53 lb in).
2. Install the NEW crankshaft rear oil seal housing gasket.
3. Install the crankshaft rear oil housing onto the crankshaft rear oil seal housing retainer stud.
4. Install the crankshaft rear oil seal housing nut and bolts. Tighten: Tighten the crankshaft rear oil seal housing nut and bolts to 12 N.m (106 lb in).
5. Apply a small amount (2 to 3 drops) of clean engine oil to the bore of the crankshaft rear oil seal housing.
6. Apply a small amount (2 to 3 drops) of clean engine oil to the outside diameter of the engine flywheel pilot flange.
7. Apply a small amount (1 drop) of clean engine oil to the outside diameter of the flywheel locator pin.
8. Apply a small amount (2 to 3 drops) of clean engine oil to the outside diameter of the crankshaft seal surface.
9. Inspect the J 35621-B flange for imperfections that may damage the crankshaft rear oil seal. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Minor imperfections may be removed with a fine grade emery cloth.
10. Remove the sleeve from the crankshaft rear oil seal.
11. Apply a small amount (2 to 3 drops) of clean engine oil to the outside diameter of the crankshaft rear oil seal.
12. Install the crankshaft rear oil seal onto the J 35621-B . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
13. Install the J 35621-B onto the rear of the crankshaft and hand tighten the tool bolts until snug. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
14. Install the crankshaft rear oil seal onto the crankshaft and into the crankshaft rear oil seal housing. Turn the J 35621-B wing nut clockwise until the crankshaft rear oil seal is installed near to flush and square to the crankshaft rear oil seal housing. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Increased resistance will be felt when the crankshaft rear oil seal has reached the bottom of the crankshaft rear oil seal housing bore. Turn the J 35621-B wing nut counterclockwise to release the. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . J 35621-B from the crankshaft rear oil seal. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
15. Remove the J 35621-B from the crankshaft. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
16. Wipe off any excess engine oil with a clean rag.

Piston, Connecting Rod, and Bearing Installation

Tools Required

1. J 5239 Connecting Rod Bolt Guide Set. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 8037 Ring Compressor. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. J 8087 Cylinder Bore Gage. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. J 45059 Angle Meter. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Piston Selection

1. Use the J 8087 in order to measure the cylinder bore diameter. Measure at a point 64 mm (2.5 in) from the top of the cylinder bore and 90 degrees to the crankshaft centerline.
2. Measure the J 8087 with a micrometer and record the reading.
3. With a micrometer or caliper at a right angle to the piston pin bore, measure the piston 11 mm (0.433 in) from the bottom of the skirt.
4. Subtract the piston diameter from the cylinder bore diameter in order to determine piston-to-bore clearance. Refer to «Engine Mechanical Specifications»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l__engine-mechanical-specifications) .
5. If the proper clearance cannot be obtained, then select another piston and measure the clearances. If the proper fit cannot be obtained, the cylinder bore may require honing or boring.
6. When the piston-to-cylinder bore clearance is within specifications, permanently mark the top of the piston for installation into the proper cylinder.

Scheme 62

1. Apply clean engine oil to the following components: The piston The piston rings The cylinder bore The bearing surfaces
2. Install the J 5239 onto the connecting rod bolts. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. Install the J 8037 onto the piston and compress the piston rings. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Install the piston and connecting rod assembly, and the J 8037 into the proper cylinder bore. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
5. Use the J 8037 and the J 5239 and lightly tap the top of the piston with a wooden hammer handle. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Hold the J 8037 firmly against the engine block until all of the piston rings have entered the cylinder bore. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Use the J 5239 in order to guide the connecting rod onto the crankshaft journal. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
6. Remove the J 5239 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
7. Install the connecting rod caps, bearings, and nuts. Tighten: Tighten the nuts evenly on the first pass to 27 N.m (20 lb ft). Use the J 45059 in order to tighten the nuts on the final pass an additional 70 degrees. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
8. After the piston and connecting rod assemblies have been installed, lightly tap each connecting rod assembly, parallel to the crankpin, in order to ensure that the connecting rods have side clearance.
9. Use a feeler gage or a dial indicator to measure the connecting rod side clearance between the connecting rod caps. The connecting rod side clearance should be 0.15-0.44 mm (0.006-0.017 in).

Camshaft Installation

1. Apply clean engine oil GM P/N 12345610 (Canadian P/N 993193) or equivalent, or engine oil supplement GM P/N 1052367 (Canadian P/N 992367) or equivalent, to the following components: The engine camshaft lobes The camshaft bearing journals The camshaft bearings The distributor drive gear
2. Install three 5/16-18 x 4.0 inch bolts into the engine camshaft front bolt holes.
3. Use the bolts as a handle in order to install the engine camshaft.
4. Remove the 3 bolts from the front of the engine camshaft.
5. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the camshaft retainer bolts.
6. Install the camshaft retainer and bolts. Tighten: Tighten the camshaft retainer bolts to 12 N.m (106 lb in).

Balance Shaft Installation

Tools Required

1. J 8092 Universal Driver Handle. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
2. J 36996 Balance Shaft Installer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
3. J 45059 Angle Meter. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

1. Apply clean engine oil GM P/N 12345610 (Canadian P/N 993193) or equivalent, to the balance shaft front bearing.
2. Use the J 36996 and the J 8092 in order to install the balance shaft.
3. Install the balance shaft retainer and bolts. Tighten: Tighten the bolts to 12 N.m (106 lb in).
4. Install the balance shaft driven gear onto the balance shaft.
5. If reusing the fastener, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the balance shaft driven gear bolt.
6. Install the balance shaft driven gear bolt. Use a wrench to secure the balance shaft. Place the wrench onto the balance shaft near to the balance shaft front bearing. Install the balance shaft driven gear bolt. Tighten: Tighten the balance shaft driven gear bolt on the first pass to 20 N.m (15 lb ft). Tighten the balance shaft driven gear bolt on the final pass using the J 45059 an additional 35 degrees. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
7. Remove the wrench from the balance shaft.
8. Rotate the balance shaft by hand in order to ensure that there is clearance between the balance shaft and the valve lifter pushrod guide. If the balance shaft does not rotate freely, check to ensure that the retaining ring on the balance shaft front bearing is seated on the case.
9. Install the balance shaft drive gear.
10. Rotate the engine camshaft so that the timing mark on the balance shaft drive gear is in the 12 o'clock position.
11. Remove the balance shaft drive gear.
12. Rotate the balance shaft so that the timing mark on the balance shaft driven gear is in the 6 o'clock position.
13. Position the balance shaft drive gear onto the engine camshaft.
14. Look to ensure that the balance shaft drive gear and the balance shaft driven gear timing marks are aligned.

Timing Chain and Sprockets Installation

Tools Required: J 5590 Pinion Bearing Race Installer - Rear. See Special Tools and Equipment .

1. Install the crankshaft balancer key into the crankshaft keyway. The crankshaft balancer key should be parallel to the crankshaft or with a slight incline.
2. Align the keyway of the crankshaft sprocket with the crankshaft balancer key.
3. Use the J 5590 in order to install the crankshaft sprocket. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .
4. Rotate the crankshaft until the crankshaft sprocket alignment mark is at the 12 o'clock position.
5. Install the camshaft sprocket and the camshaft timing chain.
6. Look to ensure that the crankshaft sprocket is aligned at the 12 o'clock position and camshaft sprocket is aligned at the 6 o'clock position.
7. Install camshaft sprocket bolts. Tighten: Tighten the camshaft sprocket bolts to 25 N.m (18 lb ft).
8. Install the timing chain tensioner bracket and bolt (227 and 228). Tighten: Tighten the timing chain tensioner bracket bolt to 12 N.m (106 lb in).
9. Install the timing chain tensioner shoe (229) using an upwards motion.
10. Install the crankshaft position sensor reluctor ring. Align the keyway on the crankshaft position sensor reluctor ring with the crankshaft balancer key in the crankshaft. Use the J 5590 in order to push the crankshaft position sensor reluctor ring onto the crankshaft until completely seated against the crankshaft sprocket. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) .

Engine Front Cover Installation

1. Install the NEW engine front cover.
2. Install the engine front cover bolts. Tighten: Tighten the bolts to 12 N.m (106 lb in).
3. Lubricate the NEW crankshaft position sensor seal, O-ring, with clean engine oil.
4. Install the NEW crankshaft position sensor seal, O-ring, onto the crankshaft position sensor.
5. Install crankshaft position sensor until fully seated into the engine front cover.
6. Install crankshaft position sensor bolt. Tighten: Tighten the crankshaft position sensor bolt to 8 N.m (71 lb in).

Oil Pump Installation

1. Inspect for properly installed oil pump locator pins.
2. Install the oil pump.
3. Position the oil pump onto the pins.
4. Install the oil pump bolt attaching the oil pump to the rear crankshaft bearing cap. Tighten: Tighten the oil pump bolt to 90 N.m (66 lb ft).

Oil Pan Installation

1. Apply a 5 mm (0.197 in) wide and 25 mm (1.0 in) long bead of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent, to both the right and left sides of the engine front cover to engine block junction at the oil pan sealing surfaces.
2. Apply a 5 mm (0.197 in) wide and 25 mm (1.0 in) long bead of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent, to the entire crankshaft rear oil seal housing to engine block junction at the oil pan sealing surfaces.
3. Install the NEW oil pan gasket into the groove in the oil pan.
4. Install the oil pan onto the engine block. Press the oil pan gasket into the grooves of the engine front cover and crankshaft rear oil seal housing.
5. Slide the oil pan back against a suitable straight edge.
6. Install the oil pan bolts and nuts, but do not tighten.
7. Measure the pan-to-transmission housing clearance using a feeler gage and a straight edge. Use a feeler gage to check the clearance between the oil pan-to-transmission housing measurement points. If the clearance exceeds 0.3 mm (0.011 in) at any of the 3 oil pan-to-transmission housing measurement points (1), then repeat the step until the oil pan-to-transmission housing clearance is within the specification. The oil pan must always be forward of the rear face of the engine block.
8. Tighten the oil pan bolts and nuts in sequence (1-12). Tighten: Tighten the oil pan bolts to 25 N.m (18 lb ft).
9. Measure the clearance between the 3 oil pan-to-transmission housing measurement points in order to ensure proper alignment.
10. Install a NEW oil pan drain plug seal, O-ring, onto the oil pan drain plug.
11. Install the oil pan drain plug into the oil pan. Tighten: Tighten the oil pan drain plug to 25 N.m (18 lb ft).

Oil Filter Adapter Installation

1. Install the NEW oil filter adapter seal, O-ring, into the groove in the oil filter adapter.
2. Install the oil filter adapter and NEW oil filter adapter gasket.
3. Install the oil filter adapter bolts. Tighten: Tighten the oil filter adapter bolts to 21 N.m (15 lb ft).

Crankshaft Balancer Installation

Tools Required: J 23523-F Balancer Remover and Installer. See Special Tools and Equipment .

1. Look to ensure that the crankshaft balancer front groove pin is installed in the proper location, if applicable. The length and location of the pins must be the same as the original length and location.
2. Apply a small amount of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent, onto the crankshaft balancer keyway in order to seal the crankshaft balancer keyway and crankshaft joint.
3. Align the keyway of the crankshaft balancer with the crankshaft balancer key.
4. Install the crankshaft balancer onto the end of the crankshaft.
5. Use the J 23523-F in order to press the crankshaft balancer onto the crankshaft. Install the J 23523-F plate and bolts onto the front of the crankshaft balancer. Tighten: Tighten the J 23523-F plate bolts to 25 N.m (18 lb ft). Install the J 23523-F screw into the end for the crankshaft. Install the J 23523-F bearing, the washer, and the nut onto the J 23523-F screw. Rotate the J 23523-F nut clockwise until the crankshaft balancer hub is completely seated against the crankshaft position sensor reluctor ring.
6. Remove the J 23523-F.
7. Install the crankshaft pulley and bolts. Finger tighten all bolts until snug. Tighten: Tighten the crankshaft pulley bolts to 58 N.m (43 lb ft).
8. Ensure that the crown of the crankshaft balancer washer (2) is faced away from the engine.
9. Install the crankshaft balancer washer and the bolt. Tighten: Tighten the crankshaft balancer bolt to 95 N.m (70 lb ft).

Valve Lifter Installation

1. Apply lubricant GM P/N 12345501 (Canadian P/N 992704) or equivalent, to the valve lifter rollers.
2. Install the valve lifters.
3. Install the valve lifter pushrod guides. Tighten: Tighten the valve lifter pushrod guide bolts to 16 N.m (12 lb ft).

Cylinder Head Installation - Left

Tools Required: J 45059 Angle Meter. See Special Tools and Equipment .

1. Clean the cylinder head gasket surfaces on the engine block.
2. Inspect the cylinder head locator dowel pins for proper installation. The installation height should be 6.3-6.5 mm (0.248-0.256 in) (a).
3. Clean the cylinder head gasket surfaces on the cylinder head.
4. Install the NEW cylinder head gasket in position over the cylinder head locator dowel pins.
5. Install the cylinder head onto the engine block. Guide the cylinder head carefully into place over the dowel pins and the cylinder head gasket.
6. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the NEW cylinder head bolts.
7. Install the NEW cylinder head bolts finger tight.
8. Tighten the cylinder head bolts in sequence on the first pass. Tighten: Tighten the bolts in sequence on the first pass to 30 N.m (22 lb ft).
9. Use the J 45059 in order to tighten the cylinder head bolts in sequence on the final pass. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten: Tighten the long bolts (1, 4, 5, 8, and 9) on the final pass in sequence to 75 degrees. Tighten the medium bolts (12 and 13) on the final pass in sequence to 65 degrees. Tighten the short bolts (2, 3, 6, 7, 10, and 11) on the final pass in sequence to 55 degrees.
10. Install the spark plug wire support and bolts. Tighten: Tighten the spark plug wire support bolts to 12 N.m (106 lb in).
11. Measure the NEW spark plugs for the proper gap. Adjust the spark plug gap if necessary. Specification: Spark plug gap to 1.52 mm (0.060 in).
12. Install the spark plugs. Tighten: Tighten the spark plugs for a USED cylinder head to 15 N.m (11 lb ft). Tighten the spark plugs for the initial installation of a NEW cylinder head to 30 N.m (22 lb ft).
13. If reusing the engine coolant temperature gage sensor, if applicable, apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the engine coolant temperature gage sensor.
14. Install the engine coolant temperature gage sensor, if applicable. Tighten: Tighten the engine coolant temperature gage sensor to 20 N.m (15 lb ft).
15. If reusing the engine coolant temperature sensor, if applicable, apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the engine coolant temperature gage sensor.
16. Install the engine coolant temperature sensor, if applicable. Tighten: Tighten the engine coolant temperature sensor to 20 N.m (15 lb ft).

Cylinder Head Installation - Right

Tools Required: J 45059 Angle Meter. See Special Tools and Equipment .

1. Clean the cylinder head gasket surfaces on the engine block.
2. Inspect the cylinder head locator dowel pins for proper installation. The installation height should be 6.3-6.5 mm (0.248-0.256 in) (a).
3. Clean the cylinder head gasket surfaces on the cylinder head.
4. Install the NEW cylinder head gasket in position over the cylinder head locator dowel pins.
5. Install the cylinder head onto the engine block. Guide the cylinder head carefully into place over the dowel pins and the cylinder head gasket.
6. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the NEW cylinder head bolts.
7. Install the NEW cylinder head bolts finger tight.
8. Tighten the cylinder head bolts in sequence on the first pass. Tighten: Tighten the bolts in sequence on the first pass to 30 N.m (22 lb ft).
9. Use the J 45059 in order to tighten the cylinder head bolts in sequence on the final pass. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten: Tighten the long bolts (1, 4, 5, 8, and 9) on the final pass in sequence to 75 degrees. Tighten the medium bolts (12 and 13) on the final pass in sequence to 65 degrees. Tighten the short bolts (2, 3, 6, 7, 10, and 11) on the final pass in sequence to 55 degrees.
10. Install the spark plug wire support and bolts. Tighten: Tighten only the rear spark plug wire support bolt to 12 N.m (106 lb in).
11. Remove the front spark plug wire support bolt. The front spark plug wire support bolt is used to fasten the oil level indicator tube, and will be installed within the oil level indicator tube installation procedure.
12. Measure the NEW spark plugs for the proper gap. Adjust the spark plug gap if necessary. Specification: Spark plug gap to 1.52 mm (0.060 in).
13. Install the spark plugs. Tighten: Tighten the spark plugs for a USED cylinder head to 15 N.m (11 lb ft). Tighten the spark plugs for the initial installation of a NEW cylinder head to 30 N.m (22 lb ft).

Valve Rocker Arm and Push Rod Installation

1. Install the valve pushrods.
2. Install the valve rocker arm supports.
3. Apply prelube GM P/N 12345501 (Canadian P/N 992704) or equivalent, to the following valve rocker arm contact surfaces: Valve pushrod socket (1) Roller pivot (2) Valve stem tip (3)
4. Install the valve rocker arm assemblies as follows: Finger start the bolt at location (1) Finger start the bolt at location (2) Finger start the bolt at location (3) Finger start the remaining valve rocker arm bolts
5. Rotate the crankshaft balancer clockwise until the alignment marks on the crankshaft balancer are aligned with the tabs on the engine front cover, 1 with 2 and 3 with 4. At that point the number 1 piston should be at TDC of the compression stroke.
6. Tighten the valve rocker arm bolts. Tighten: Tighten valve rocker arm bolts to 30 N.m (22 lb ft).

Intake Manifold Installation

1. Apply a 4.0 mm (0.157 in) patch of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent, to the cylinder head side of the lower intake manifold gasket at each end.
2. Install the lower intake manifold gasket onto the cylinder head. Use the gasket locator pins in order to properly seat the lower intake manifold gasket on the cylinder head.
3. Apply a 5 mm (0.197 in) bead of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent, to the front top of the engine block.
4. Extend the adhesive bead 13 mm (0.50 in) onto each lower intake manifold gasket.
5. Apply a 5 mm (0.197 in) bead of adhesive GM P/N 12346141 (Canadian P/N 10953433) or equivalent, to the rear top of the engine block.
6. Extend the adhesive bead 13 mm (0.50 in) onto each lower intake manifold gasket.
7. Install the lower intake manifold onto the engine block.
8. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the lower intake manifold bolts.
9. Install the lower intake manifold bolts.
10. Tighten the lower intake manifold bolts. Tighten: Tighten the bolts on the first pass in sequence (1-8) to 3 N.m (27 lb in). Tighten the bolts on the second pass in sequence (1-8) to 12 N.m (106 lb in). Tighten the bolts on the final pass in sequence (1-8) to 15 N.m (11 lb ft).
11. Connect the evaporative emission (EVAP) canister solenoid valve harness. Push the elbow inward until the quick connect snaps into place. Pull the elbow outward in order to ensure proper connection.

Distributor Installation

1. Rotate the crankshaft balancer clockwise until the alignment marks on the crankshaft balancer are aligned with the tabs on the engine front cover and the number 1 piston is at top dead center of the compression stroke.
2. Remove the distributor cap bolts and discard.
3. Remove the distributor cap.
4. Install a NEW distributor gasket onto the distributor.
5. Align the indent hole on the driven gear with the paint mark on the distributor housing.
6. Ensure that the distributor rotor segment points to the cap hold area.
7. Align the slotted tang in the oil pump driveshaft with the distributor driveshaft. Rotate the oil pump driveshaft with a screwdriver if necessary.
8. Align the flat (1) in the distributor housing toward the front of the engine.
9. Install the distributor and distributor clamp. The flat in the distributor housing must point toward the front of the engine.
10. Once the distributor is fully seated, align the distributor rotor segment with the number 6 pointer (1) that is cast into the distributor base. If the distributor rotor segment does not come within a few degrees of the number 6 pointer (1), the gear mesh between the distributor and camshaft may be off a tooth or more. Repeat the procedure again in order to achieve proper alignment.
11. Install the distributor clamp bolt. Tighten: Tighten the distributor clamp bolt to 25 N.m (18 lb ft).
12. Install the distributor cap and NEW distributor cap bolts. Tighten: Tighten the distributor cap bolts to 2.4 N.m (21 lb in).
13. Install the ignition coil wire harness.

Valve Rocker Arm Cover Installation - Left

1. Install the NEW valve rocker arm cover gasket into the groove of the valve rocker arm cover.
2. Install the NEW valve rocker arm cover bolt grommets into the valve rocker arm cover.
3. Install the valve rocker arm cover onto the cylinder head.
4. Install the valve rocker arm cover bolts. Tighten: Tighten the valve rocker arm cover bolts to 12 N.m (106 lb in).

Valve Rocker Arm Cover Installation - Right

1. Install the NEW valve rocker arm cover gasket into the groove of the valve rocker arm cover.
2. Install the NEW valve rocker arm cover bolt grommets into the valve rocker arm cover.
3. Install the valve rocker arm cover onto the cylinder head.
4. Install the valve rocker arm cover bolts. Tighten: Tighten the valve rocker arm cover bolts to 12 N.m (106 lb in).

Oil Level Indicator and Tube Installation

1. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, around the oil level indicator tube 13 mm (0.5 in) below the tube bead.
2. Install the oil level indicator tube into the engine block. Rotate the oil level indicator tube into position.
3. Install the oil level indicator tube bolt. Tighten: Tighten the oil level indicator tube bolt to 12 N.m (106 lb in).
4. Install the oil level indicator into the oil level indicator tube, if required.

Water Pump Installation

Tools Required: J 41240 Fan Clutch Remover and Installer. See Special Tools and Equipment .

1. If reusing the fasteners, apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the water pump bolts.
2. Install the water pump and the NEW water pump gaskets.
3. Install the water pump bolts. Tighten: Tighten the water pump bolts to 45 N.m (33 lb ft).
4. Install the water pump inlet hose and the water pump inlet hose clamps.
5. Install the fan and water pump pulley and bolts using the J 41240 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-43l) . Tighten: Tighten the fan and water pump pulley bolts to 25 N.m (18 lb ft).

Exhaust Manifold Installation - Left

1. Install the NEW exhaust manifold gaskets.
2. Install the exhaust manifold.
3. Install the spark plug wire shields.
4. If reusing the fasteners, apply threadlock GM P/N 12345493 (Canadian P/N 10953488) or equivalent, to the threads of the exhaust manifold bolts and stud.
5. Install the exhaust manifold bolts and stud. Tighten: Tighten the exhaust manifold bolts and stud on the first pass to 15 N.m (11 lb ft). Tighten the exhaust manifold bolts and stud on the final pass to 30 N.m (22 lb ft).
6. Install the spark plug wires to the spark plug wire retainers.
7. Install the spark plug wires onto the spark plugs.

Exhaust Manifold Installation - Right

1. Install the NEW exhaust manifold gaskets.
2. Install the exhaust manifold.
3. Install the spark plug wire shields.
4. If reusing the fasteners, apply threadlock GM P/N 12345493 (Canadian P/N 10953488) or equivalent, to the threads of the exhaust manifold bolts.
5. Install the exhaust manifold bolts. Tighten: Tighten the exhaust manifold bolts on the first pass to 15 N.m (11 lb ft). Tighten the exhaust manifold bolts on the final pass to 30 N.m (22 lb ft).
6. Install the spark plug wires to the spark plug wire retainers.
7. Install the spark plug wires onto the spark plugs.

Engine Flywheel Installation

1. Install the engine flywheel to the crankshaft.
2. Align the locator hole to the pin.
3. Install the engine flywheel bolts. Tighten: Tighten the engine flywheel bolts in sequence to 100 N.m (74 lb ft).

Crankcase Ventilation System Description

A crankcase ventilation system is used in order to provide a more complete scavenging of crankcase vapors. The air cleaner supplies fresh air through a filter to the crankcase. The crankcase mixes the fresh air with blow-by gases. This mixture then passes through a crankcase ventilation valve into the intake manifold.

The primary control is through the crankcase ventilation valve (1), which meters the flow at a rate depending on the manifold vacuum.

In order to maintain an idle quality, the crankcase ventilation valve restricts the flow when the intake manifold vacuum is high. If abnormal operating conditions arise, the system is designed in order to allow the excessive amounts of blow-by gases to back flow through the crankcase vent tube into the air cleaner in order to be consumed by normal combustion.

Scheme 63

Drive Belt System Description

The drive belt system consists of the following components

1. The drive belt
2. The drive belt tensioner
3. The drive belt idler pulley
4. The crankshaft balancer pulley
5. The accessory drive component mounting brackets
6. The accessory drive components The power steering pump, if belt driven The generator The A/C compressor, if equipped The engine cooling fan, if belt driven The water pump, if belt driven The vacuum pump, if equipped The air compressor, if equipped

The drive belt system may use 1 belt or 2 belts. The drive belt is thin so that it can bend backwards and has several ribs to match the grooves in the pulleys. There also may be a V-belt style belt used to drive certain accessory drive components. The drive belts are made of different types of rubbers - chloroprene or EPDM - and have different layers or plys containing either fiber cloth or cords for reinforcement.

Both sides of the drive belt may be used to drive the different accessory drive components. When the back side of the drive belt is used to drive a pulley, the pulley is smooth.

The drive belt is pulled by the crankshaft balancer pulley across the accessory drive component pulleys. The spring loaded drive belt tensioner keeps constant tension on the drive belt to prevent the drive belt from slipping. The drive belt tensioner arm will move when loads are applied to the drive belt by the accessory drive components and the crankshaft.

The drive belt system may have an idler pulley, which is used to add wrap to the adjacent pulleys. Some systems use an idler pulley in place of an accessory drive component when the vehicle is not equipped with the accessory.

Balance Shaft

The cast iron balance shaft is mounted in the crankcase above and in-line with the camshaft. A camshaft gear drives the gear attached to the balance shaft. The front end of the balance shaft is supported by a ball-type bearing. The rear end of the balance shaft uses a sleeve-type bearing.

Camshaft

The steel camshaft is supported by four bearings pressed into the engine block. The camshaft timing chain sprocket mounted to the front of the camshaft is driven by the crankshaft sprocket through a camshaft timing chain.

Crankshaft

The cast nodular iron crankshaft is supported by four crankshaft bearings. The number four crankshaft bearing at the rear of the engine is the end thrust bearing. The crankshaft bearings are retained by bearing caps that are machined with the engine block for proper alignment and clearances. The crankshaft position sensor reluctor ring has three lugs used for crankshaft timing and is constructed of powdered metal. The crankshaft position sensor reluctor ring has a slight interference fit onto the crankshaft and an internal keyway for correct positioning.

Cylinder Heads

The cast iron cylinder heads have one intake and one exhaust valve for each cylinder. A spark plug is located between the valves in the side of the cylinder head. The valve guides and seats are integral to the cylinder head. The 4.3L heavy duty applications have pressed in exhaust valve seats. The valve rocker arms are positioned on the valve rocker arm supports and retained by a bolt.

Engine Block

The cast iron engine block has six cylinders arranged in a V shape with three cylinders in each bank. Starting at the front side of the engine block, the cylinders in the left bank are numbered 1-3-5 and cylinders in the right bank are numbered 2-4-6 when viewed from the rear. The firing order of the cylinders is 1-6-5-4-3-2. The cylinders are encircled by coolant jackets.

Exhaust Manifolds

The cast iron exhaust manifolds direct exhaust gases from the combustion chambers to the exhaust system.

Intake Manifold

The intake manifold is a two-piece design. The upper portion is made from a composite material and the lower portion is cast aluminum. The throttle body attaches to the upper manifold. The Central Multipoint Flexible Injection (MFI) system uses multiple fuel injectors to meter and distribute fuel to each engine cylinder. The MFI is retained by a bracket bolted to the lower intake manifold. The fuel meter body also houses the pressure regulator. Metal inlet and outlet fuel lines and nylon delivery tubes connect to the Central MFI unit. The delivery tubes independently distribute fuel to each cylinder through injectors located at the port entrance of each manifold runner where the fuel is atomized.

Piston and Connecting Rod Assemblies

The cast aluminum pistons use two compression rings and one oil control assembly. The piston is a low friction, lightweight design with a flat top and barrel shaped skirt. The piston pins are offset 0.9 mm (0.0354 in) toward the major thrust side (right side) to reduce piston slap as the connecting rod travels from one side of the piston to the other side after a stroke. The piston pins have a floating fit in the piston and are retained by a press fit in the connecting rod. The connecting rods are forged steel. The connecting rods are machined with the rod cap installed for proper clearances and alignments.

Valve Train

Motion is transmitted from the camshaft through the hydraulic roller valve lifters and the tubular valve pushrods to the roller type valve rocker arms. The roller type valve rocker arm pivots on a needle type bearing in order to open the valve. The valve rocker arms for each bank of cylinders are mounted to a one piece valve rocker arm support. Each valve rocker arm is retained on the valve rocker arm support and the cylinder head by a bolt. The hydraulic valve lifters keep all the parts of the valve train in constant contact. Each hydraulic valve lifter acts as an automatic adjuster and maintains zero lash in the valve train. This eliminates the need for periodic valve adjustment.

New Product Information

The purpose of New Product Information is to highlight or indicate important product changes from the previous model year.

Changes may include one or more of the following items

1. A component comparison from the previous year
2. Fastener changes
3. Torque values and/or fastener tightening strategies
4. Changed engine specifications
5. New sealants and/or adhesives
6. Disassembly and assembly procedure revisions
7. Engine mechanical diagnostic procedure revisions
8. New special tools required

Component Comparison

1. Engine Oil Level Sensor has been deleted completely in 2004
2. Timing Chain Tensioner has been added

Torque Values and/or Fastener Tightening Strategies

Addition of timing tensioner bolt torque

Changed Engine Specifications

No changes for 2004.

New Sealants and/or Adhesives

No new sealants or adhesives for 2004.

Disassembly and Assembly Procedure Revisions

Timing chain disassembly and assembly procedures changed due to the addition of the timing chain tensioner.

Engine Mechanical Diagnostic Procedure Revisions

No changes for 2004.

New Special Tools Required

1. J 45059 Angle Meter has been added
2. J 36660-A Torque Angle Meter has been deleted for 2004

Lubrication Description

Full pressure lubrication, through a full-flow oil filter is supplied by a gear-type oil pump. Oil is drawn up through the oil pump screen and passes through the pump to the oil filter. The oil filter is a full-flow paper element unit with an anti-drain back valve. An oil filter bypass valve is used to ensure adequate oil supply, in the event the filter becomes plugged or develops excessive pressure drop. Filtered oil flows into the main gallery and then to the camshaft, the balance shaft, the rear bearing, and the crankshaft bearings. The valve lifter oil gallery supplies oil to the valve lifters. Oil flows from the valve lifters through the hollow valve pushrods to the valve rocker arms. Oil drains back to the crankcase through the oil drain holes in the cylinder head. The camshaft timing chain is drip fed from the front camshaft bearing. The pistons and piston pins are lubricated by oil splash.

Scheme 64

Cleanliness and Care

1. Throughout this section, it should be understood that proper cleaning and protection of machined surfaces and friction areas is part of the repair procedure. This is considered standard shop practice even if not specifically stated.
2. When any internal engine parts are serviced, care and cleanliness is important.
3. When components are removed for service, the components should be marked, organized or retained in a specific order for re-assembly.
4. At the time of installation, the components should be installed in the same location and with the same mating surface as when removed.
5. An automobile engine is a combination of many machined, honed, polished and lapped surfaces with tolerances that are measured in millimeters or thousandths of an inch. The surfaces should be protected to avoid component damage.
6. Apply a liberal amount of clean engine oil to friction areas during assembly.
7. Proper lubrication will protect and lubricate friction areas during initial operation.

Separating Parts

Mark or identify the following components

1. Piston and the piston pin
2. Piston to the specific cylinder bore
3. Piston rings to the specific cylinder bore
4. Connecting rod to the crankshaft journal
5. Connecting rod to connecting rod cap
6. Crankshaft bearings and connecting rod bearings
7. Engine camshaft and valve lifters
8. Valve lifters, valve rocker arms, and valve rocker arm supports
9. Valve to the valve guide
10. Valve spring to cylinder head location
11. Engine block bearing cap location and direction
12. Oil pump drive and driven gears

Gasket Reuse and Applying Sealant

1. Do not reuse any gasket unless specified.
2. Gaskets that can be reused will be identified in the service procedure.
3. Do not apply sealant to any gasket or sealing surface unless specified in the service procedure.

Separating Components

1. Use a rubber mallet in order to separate the components.
2. Bump the part sideways in order to loosen the components.
3. Bumping of the component should be done at bends or reinforced areas of the component to prevent distortion of the components.

Cleaning Gasket Surfaces

1. Use care to avoid gouging or scraping the sealing surfaces.
2. Use a plastic or wood scraper in order to remove all the sealant from the components. Do not use any other method or technique to remove the sealant or the gasket material from a part.
3. Do not use abrasive pads, sand paper, or power tools to clean the gasket surfaces. These methods of cleaning can cause damage to the component sealing surfaces. Abrasive pads also produce a fine grit that the oil filter cannot remove from the engine oil. This fine grit is an abrasive and can cause internal engine damage.

Assembling Components

1. Assemble components using only the sealant (or equivalent) that is specified in the service procedure.
2. Sealing surfaces must be clean and free of debris or oil.
3. Specific components such as crankshaft oil seals or valve stem oil seals may require lubrication during assembly.
4. Components requiring lubrication will be identified in the service procedure.
5. Apply only the amount of sealant specified in the service procedure to a component.
6. Do not allow the sealant to enter into any blind threaded holes, as the sealant may prevent the fastener from clamping properly or cause component damage when tightened.
7. Tighten the fasteners to the proper specifications.

Sealant Types

The following 2 major types of sealant are commonly used in engines

1. Anaerobic sealant room temperature vulcanizing (RTV)
2. Anaerobic sealant, which include the following: Gasket eliminator Pipe Threadlock

Anaerobic Type Room Temperature Vulcanizing (RTV) Sealant

Anaerobic type room temperature vulcanizing (RTV) sealant cures when exposed to air. This type of sealant is used where 2 components, such as the intake manifold and the engine block, are assembled together.

Use the following information when using RTV sealant

1. Do not use RTV sealant in areas where extreme temperatures are expected. These areas include: The exhaust manifold The head gasket Any other surfaces where a different type of sealant is specified in the service procedure
2. Always follow all the safety recommendations and the directions that are on the RTV sealant container.
3. Use a plastic or wood scraper in order to remove all the RTV sealant from the components.
4. The surfaces to be sealed must be clean and dry.
5. Use a RTV sealant bead size as specified in the service procedure.
6. Apply the RTV sealant bead to the inside of any bolt holes areas.
7. Assemble the components while the RTV sealant is still wet to the touch, within 3 minutes.
8. Tighten the fasteners in sequence, if specified, and to the proper torque specifications.

Anaerobic Type Gasket Eliminator Sealant

Anaerobic type gasket eliminator sealant cures in the absence of air. This type of sealant is used where 2 rigid parts, such as castings, are assembled together. When 2 rigid parts are disassembled and no sealant or gasket is readily noticeable, then the 2 parts were probably assembled using an anaerobic type gasket eliminator sealant.

Use the following information when using gasket eliminator sealant

1. Always follow all the safety recommendations and directions that are on the gasket eliminator sealant container.
2. Apply a continuous bead of gasket eliminator sealant to one flange. The surfaces to be sealed must be clean and dry.

Note. Do not allow the sealant to enter a blind hole. The sealant may prevent the fastener from achieving proper clamp load, cause component damage when the fastener is tightened, or lead to component failure.

Anaerobic Type Threadlock Sealant

Anaerobic type threadlock sealant cures in the absence of air. This type of sealant is used for threadlocking and sealing of bolts, fittings, nuts, and studs. This type of sealant cures only when confined between 2 close fitting metal surfaces.

Use the following information when using threadlock sealant

1. Always follow all safety recommendations and directions that are on the threadlock sealant container.
2. The threaded surfaces to be sealed must be clean and dry.
3. Apply the threadlock sealant as specified on the threadlock sealant container.
4. Tighten the fasteners in sequence, if specified, and to the proper torque specifications.

Anaerobic Type Pipe Sealant

Anaerobic type pipe sealant cures in the absence of air and remains pliable when cured. This type of sealant is used where 2 parts are assembled together and require a leak proof joint.

Use the following information when using pipe sealant

1. Do not use pipe sealant in areas where extreme temperatures are expected. These areas include: The exhaust manifold The head gasket Surfaces where a different sealant is specified
2. Always follow all the safety recommendations and the directions that are on the pipe sealant container.
3. The surfaces to be sealed must be clean and dry.
4. Use a pipe sealant bead of the size or quantity as specified in the service procedure.
5. Apply the pipe sealant bead to the inside of any bolt hole areas.
6. Apply a continuous bead of pipe sealant to one sealing surface.
7. Tighten the fasteners in sequence, if specified, and to the proper torque specifications.

Tools and Equipment

Special tools are listed and illustrated throughout this section with a complete listing at the end of the section. The tools (or the equivalents) are specially designed to quickly and safely accomplish the operations for which the tools are intended. The use of special tools will also minimize possible damage to engine components. Some precision measuring tools are required for inspection of certain critical components. Torque wrenches and a torque angle meter are necessary for the proper tightening of various fasteners.

To properly service the engine assembly, the following items should be readily available

1. Approved eye protection and safety gloves
2. A clean, well-lit, work area
3. A suitable parts cleaning tank
4. A compressed air supply
5. Trays or storage containers to keep parts and fasteners organized
6. An adequate set of hand tools
7. Approved engine repair stand
8. An approved engine lifting device that will adequately support the weight of the components

Special Tools

Special Tools Illustration Tool Number / Description J 3049-A Valve Lifter Remover J 5239 Connecting Rod Bolt Guide Set J 5590 Pinion Bearing Race Installer-Rear J 5825-A Crankshaft Gear Remover J 5830-02 Valve Guide Reamer Set J 5892-D Valve Spring Compressor J 7872 Magnetic Base Dial Indicator J 8001 Dial Indicator Set J 8037 Ring Compressor J 8062 Valve Spring Compressor J 8087 Cylinder Bore Gage J 8089 Carbon Removing Brush J 8092 Universal Driver Handle J 9666 Valve Spring Tester J 21882 Oil Suction Pipe Installer J 22794 Spark Plug Port Adapter J 23523-F Balancer Remover and Installer J 24086-C Piston Pin Remover/Installer J 24270 Cylinder Bore Ridge Reamer J 26941 Bushing/Bearing Remover J 28428-E High Intensity Black Light Kit J 33049 Camshaft Bearing Service Kit J 35468 Cover Aligner/Seal Installer J 35621-B Rear Main Seal Installer J 35667-A Cylinder Head Leakdown Tester J 36996 Balance Shaft Installer J 38606 Valve Spring Compressor J 38834 Balance Shaft Service Kit J 41240 Fan Clutch Remover and Installer J 41427 Engine Lift Bracket J 41712 Oil Pressure Switch Socket J 42073 Valve Stem Seal Installer J 43690 Rod Bearing Clearance Checking Tool J 45059 Angle Meter J 45299 Engine Preluber

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See also:
• Diagnostic System Check - Engine Controls
• Strategy Based Diagnosis
• Checking Aftermarket Accessories
• Spark Plug Inspection
• Battery Disconnect Caution
• Spark Plug Replacement
• Diagnostic Starting Point - Vibration Diagnosis and Correction
• Fan Clutch Replacement
• Fastener Notice
• Engine Mounting Notice
• Lifting and Jacking the Vehicle
• Starter Motor Replacement (4.8L, 5.3L, and 6.0L)
• Engine Cover Replacement
• Cruise Control Cable Replacement
• Heater Hose Replacement - Inlet
• Power Steering Pulley Replacement
• Exhaust Manifold Replacement - Left (4.3L)
• Refrigerant Recovery and Recharging
• Differential Carrier Assembly Replacement
• Transmission Replacement
• Air Cleaner Assembly Replacement
• Bumper Replacement - Front
• Grille Replacement (Uplevel)
• Radiator Support Replacement
• Power Steering Pump Replacement (4.3L)
• Capacities - Approximate Fluid
• Explanation of Scheduled Services
• Safety Glasses Caution
• Disassembled Views
• Lubrication Description
• New Product Information
• Drive Belt System Description
• Base Engine Misfire without Internal Engine Noises
• Base Engine Misfire with Abnormal Internal Lower Engine Noises
• Base Engine Misfire with Abnormal Valve Train Noise
• Base Engine Misfire with Coolant Consumption
• Base Engine Misfire with Excessive Oil Consumption
• Engine Compression Test
• Engine Noise on Start-Up, but Only Lasting a Few Seconds
• Upper Engine Noise, Regardless of Engine Speed
• Lower Engine Noise, Regardless of Engine Speed
• Engine Noise Under Load
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Oil Consumption Diagnosis
• Oil Pressure Diagnosis and Testing
• Oil Leak Diagnosis
• Cylinder Head Cleaning and Inspection
• Piston, Connecting Rod, and Bearing Removal
• Piston, Connecting Rod, and Bearing Installation
• Engine Block Cleaning and Inspection
• Fastener Tightening Specifications
• Intake Manifold Disassemble (LU3)
• Camshaft and Bearings Cleaning and Inspection
• Cylinder Head Disassemble
• Cylinder Head Assemble
• Timing Chain, Sprockets, and/or Tensioner Replacement
• Balance Shaft Replacement
• Oil Pump Cleaning and Inspection
• Engine Mechanical Specifications