Engine Mechanical - 4.8l, 5.3l & 6.0l Chevrolet Chevy Express H2500

Fastener Tightening Specifications

TORQUE SPECIFICATIONS

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Engine Mechanical Specifications (LR4 VIN V)

ENGINE MECHANICAL SPECIFICATIONS (LR4 VIN V)

Engine Mechanical Specifications (LM7 VIN T)

ENGINE MECHANICAL SPECIFICATIONS (LM7 VIN T)

Engine Mechanical Specifications (LQ4 VIN U)

ENGINE MECHANICAL SPECIFICATIONS (LQ4 VIN U)

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The vehicle identification number (VIN) is located on the left side rear of the engine block (1) and is typically a nine digit number stamped or laser-etched onto the engine at the vehicle assembly plant.

1. The first digit identifies the division.
2. The second digit identifies the model year.
3. The third digit identifies the assembly plant.
4. The fourth through ninth digits are the last six digits of the VIN.

Diagnostic Starting Point - Engine Mechanical

Begin the system diagnosis by reviewing the Disassembled Views , Engine Component Description , Lubrication Description , New Product Information and 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-h2500/2003-2003/remont/testing-diagnostics/#engine-controls-self-diagnostics-48l-53l-60l-gasoline) 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-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) , «Engine Component Description»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) , «Lubrication Description»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) , «New Product Information»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__new-product-information) and «Drive Belt System Description»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__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 condition. The diagnostic flow is the place to start when repairs are necessary.

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Engine.
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-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
2. «Base Engine Misfire with Abnormal Internal Lower Engine Noises»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
3. «Base Engine Misfire with Abnormal Valve Train Noise»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
4. «Base Engine Misfire with Coolant Consumption»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
5. «Base Engine Misfire with Excessive Oil Consumption»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
6. «Engine Compression Test»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-compression-test)
7. «Engine Noise on Start-Up, but Only Lasting a Few Seconds»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
8. «Upper Engine Noise, Regardless of Engine Speed»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
9. «Lower Engine Noise, Regardless of Engine Speed»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
10. «Engine Noise Under Load»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
11. «Engine Will Not Crank - Crankshaft Will Not Rotate»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
12. «Coolant in Combustion Chamber»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
13. «Coolant in Engine Oil»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
14. «Oil Consumption Diagnosis»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
15. «Oil Pressure Diagnosis and Testing»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__oil-pressure-diagnosis-and-testing)
16. «Oil Leak Diagnosis»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
17. «Cylinder Leakage Test»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-leakage-test)
18. «Drive Belt Chirping Diagnosis»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
19. «Drive Belt Squeal Diagnosis»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
20. «Drive Belt Whine Diagnosis»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
21. «Drive Belt Rumbling Diagnosis»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
22. «Drive Belt Vibration Diagnosis»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
23. «Drive Belt Falls Off Diagnosis»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
24. «Drive Belt Excessive Wear Diagnosis»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
25. «Drive Belt Tensioner Diagnosis»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)

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Engine Compression Test

1. Charge the battery if the battery is not fully charged.
2. Disable the ignition system.
3. Disable the fuel injection system.
4. Remove all the spark plugs.
5. Block the throttle plate wide open.
6. Start with the compression gage at zero and crank the engine through four compression strokes, four puffs.
7. Make the compression check for each cylinder. Record the reading.
8. If a cylinder has low compression, inject approximately 15 ml (1 tablespoon) of engine oil into the combustion chamber through the spark plug hole. Check the compression again and record the reading.
9. 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). (1035 x 70% = 725) (150 x 70% = 105). Normal - Compression builds up quickly and evenly to the specified compression for each cylinder. Piston Rings Leaking - Compression is low on the first stroke. Compression then builds up with the following strokes but does not reach normal. Compression improves considerably when you add oil. Valves Leaking - Compression is low on the first stroke. Compression usually does not build up on the following strokes. Compression does not improve much when you add oil. If two adjacent cylinders have lower than normal compression and injecting oil into the cylinders does not increase the compression, the cause may be a head gasket leaking between the cylinders.

Cylinder Leakage Test

Tools Required

J 35667-A Cylinder Head Leakdown Tester or equivalent

Important: A leakage test may be performed in order to measure cylinder/combustion chamber leakage. High cylinder leakage may indicate one or more of the following

1. Worn or burnt valves
2. Broken valve springs
3. Stuck valve lifters
4. Incorrect valve lash
5. Damaged piston
6. Worn piston rings
7. Worn or scored cylinder bore
8. Damaged cylinder head gasket
9. Cracked or damaged cylinder head
10. Cracked or damaged engine block

1. Disconnect the battery ground negative cable.
2. Remove the spark plugs. Refer to «SPARK PLUGS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-gasoline) .
3. Rotate the crankshaft to place the piston in the cylinder being tested at top dead center (TDC) of the compression stroke.
4. Install the J 35667-A or equivalent. Important: It may be necessary to hold the crankshaft balancer bolt to prevent the crankshaft from rotating.
5. Apply shop air pressure to the J 35667-A and adjust according to the manufacturers instructions.
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 noise at the throttle body or air inlet hose that may indicate a worn or burnt intake valve or a broken valve spring. Air leakage noise at the exhaust system tailpipe that may indicate a worn or burnt exhaust valve or a broken valve spring. Air leakage noise from the crankcase, oil level indicator tube, or oil fill tube that may indicate worn piston rings, a damaged piston, a worn or scored cylinder bore, a damaged engine block or a damaged cylinder head. Air bubbles in the cooling system may indicate a damaged cylinder head or a damaged cylinder head gasket.
7. Perform the leakage test on the remaining cylinders and record the values.

Scheme 779

Oil Pressure Diagnosis and Testing

Tools Required

1. J 21867 Pressure Gage
2. J 42907 Oil Pressure Testing Tool

Scheme 780

1. With the vehicle on a level surface, run the vehicle for a few minutes, allow adequate drain down time of 2-3 minutes, and measure the oil level.
2. If required, add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator.
3. Run the engine briefly, approximately 10-15 seconds, and verify low or no oil pressure on the vehicle gauge or light.
4. Listen for a noisy valve train or a knocking noise.
5. Inspect for the following: Oil diluted by water or glycol - anti freeze Foamy oil
6. Remove the oil filter and install the J 42907 .
7. Install J 21867 or equivalent to the J 42907 .
8. Run the engine and measure the engine oil pressure.
9. Compare the readings to «Engine Mechanical Specifications (LR4 VIN V)»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-mechanical-specifications-lr4-vin-v) or «Engine Mechanical Specifications (LM7 VIN T)»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-mechanical-specifications-lm7-vin-t) or «Engine Mechanical Specifications (LQ4 VIN U)»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-mechanical-specifications-lq4-vin-u) .
10. If the engine oil pressure is below specifications, inspect the engine for one or more of the following: Oil pump worn or dirty Refer to «Oil Pump Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__oil-pump-cleaning-and-inspection) . Oil pump-to-engine block bolts loose Refer to «Oil Pump, Pump Screen and Deflector Installation»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__oil-pump-pump-screen-and-deflector) . Oil pump screen loose, plugged, or damaged Oil pump screen O-ring seal missing or damaged Malfunctioning oil pump pressure regulator valve Excessive bearing clearance Cracked, porous, or restricted oil galleries Oil gallery plugs missing or incorrectly installed Refer to «Engine Block Plug Installation»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-block-plug-installation) . Broken valve lifters Repair as necessary.
11. If the oil pressure reading on the J 21867 or equivalent is within specifications, inspect for the following: Plugged or incorrect oil filter and/or malfunctioning oil bypass valve Malfunctioning oil pressure gage or sensor Repair as necessary.

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Diagnostic Aids

The chirping noise may be intermittent due to moisture on the drive belt(s) or the accessory drive pulley(s). In order to duplicate the customer's concern, it may be necessary to spray a small amount of water onto the drive belt(s). If spraying water onto the drive belt(s) duplicates the symptom, cleaning the accessory drive pulley(s) may be the most probable solution.

A loose or improper installation of a body or suspension component, or other item(s) on the vehicle may also cause the chirping noise.

Test Description

The number(s) below refer to the step(s) in the diagnostic table.

1. 2. The chirping 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 any further in this table.
2. 3. The noise may be an internal engine noise. Remove the drive belt(s) and operate the engine for a few seconds, this will verify if the chirping noise is related to the drive belt(s) or not. With the drive belt(s) removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s) removed.
3. 4. Inspect the drive belt(s) for signs of pilling. Pilling is the small balls, pills, or strings in the drive belt grooves caused by the accumulation of rubber dust.
4. 6. Misalignment of the accessory drive pulley(s) may be caused from improper mounting or incorrect installation of an accessory drive component, or the pulley may be bent inward or outward from a previous repair. Test for a misaligned accessory drive 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 removal and installation procedure for that pulley.
5. 10. Inspection of the fasteners can eliminate the possibility that a incorrect bolt, nut, spacer, or washer was installed.
6. 12. Inspection of the accessory drive pulley(s) should include inspecting for bends, dents, or other damage to the pulley(s) that would prevent the drive belt(s) from seating properly in the pulley grooves or on the smooth surface of the pulley when the back side of the drive belt is used to drive the pulley.
7. 14. Replacing the drive belt(s) when it is not damaged or there is not excessive pilling will only be a temporary repair.

Scheme 784

A loose or improper installation of a body, or suspension component, or other item(s) on the vehicle may cause the squeal noise.

If the squeal is intermittent, verify that it is not the accessory drive component(s) by varying their load(s), making sure they are operating to their maximum capacity. An overcharged air conditioning (A/C) system, a power steering system restriction or the incorrect fluid, or a failing generator are suggested items to inspect.

The number(s) below refer to the step(s) in the diagnostic table.

1. 2. The squeal 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 in this table
2. 3. The squeal may be an internal engine noise. Remove the drive belt(s) and operate the engine for a few seconds, this will verify if the squealing noise is related to the drive belt(s) or an accessory drive component. With the drive belt(s) removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s) removed.
3. 4. This test is to verify that an accessory drive component(s) does not have a seized bearing. With the belt(s) removed, test the bearings in the accessory drive component(s) for smooth operation. Also test the accessory drive component(s) with the engine operating by varying the load on the accessory drive component(s) to verify that the component(s) is operating properly.
4. 5. This test is to verify that the drive belt(s) tensioner(s) are not operating properly. If the drive belt tensioner(s) are not operating properly, proper belt tension may not be achieved to keep the drive belt(s) from slipping which could cause a squealing noise.
5. 6. This test is to verify that the drive belt(s) is not too long, which would prevent the drive belt tensioner(s) from operating properly. Also if the incorrect length drive belt(s) was installed, it may not be routed correctly and may be turning an accessory drive component in the incorrect direction.
6. 7. Misalignment of the accessory drive pulley(s) may be caused from improper mounting or incorrect installation of a accessory drive component, or the pulley may be 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 removal and installation procedure for that pulley.
7. 8. Inspect the accessory drive pulley(s) to verify that they are the correct diameter or width. Using a known good vehicle, compare the accessory drive pulleys.

Scheme 785

The drive belt(s) will not cause the whine.

If the whine is intermittent, verify that it is not the accessory drive component(s) by varying their loads, making sure they are operating to their maximum capacity. An overcharged air conditioning (A/C) system, a power steering system restriction or the incorrect fluid, or a failing generator are suggested items to inspect.

The number(s) below refer to the step(s) in the diagnostic table.

1. 3. This test is to verify that the whine is being caused by the accessory drive component(s). Remove the drive belt(s) and operate the engine for a few seconds, this will verify if the whining noise is related to the accessory drive component. With the drive belt(s) removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s) removed.
2. 4. This inspection should include checking the drive belt tensioner and the drive belt idler pulley bearings. The drive belt(s) 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 removal and installation procedure.

Scheme 786

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

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

If after replacing the drive belt(s) and completing the diagnostic table, the rumbling is only heard with the drive belt(s) installed, there might be an accessory drive component failure. Varying the load on the accessory drive component(s) may aid in identifying which component is causing the rumbling noise.

The number(s) below refer to the step(s) in 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 belt(s) is causing the rumbling. Rumbling 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. Operate the engine for a few seconds, this will verify if the rumbling noise is related to the drive belt(s) or not. With the drive belt(s) removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s) removed.
3. 4. Inspect the drive belt(s) to ensure that the drive belt(s) is not the cause of the noise. Small cracks across the ribs of the drive belt(s) will not cause the noise. Belt separation is identified by the plys of the belt separating, this may be seen at the edge of the belt or felt as a lump in the belt.
4. 5. Small amounts of pilling is a normal condition and acceptable. When the pilling is severe the drive belt(s) does not have a smooth surface for proper operation.

Scheme 787

The accessory drive components may have an affect on engine vibration. An overcharged air conditioning (A/C) system, a power steering system restriction, or the incorrect fluid, or an extra load placed on the generator are suggested items to inspect. To help identify an intermittent or an improper condition, vary the loads on the accessory drive components.

The number(s) below refer to the step(s) in the diagnostic table.

1. 2. This test is to verify that the vibration 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 belt(s) or accessory drive components may be causing the vibration. Remove the drive belt(s) and operate the engine for a few seconds, this will verify if the vibration is related to the drive belt(s) or not. With the drive belt(s) removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s) removed.
3. 4. The drive belt(s) may cause a vibration. While the drive belt(s) is removed this is the best time to inspect the condition of the drive belt(s).
4. 6. Inspection of the fasteners can eliminate the possibility that a incorrect 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 smooth operation. Inspect for a bent fan shaft or bent mounting flange.
6. 9. Inspect the water pump drive shaft for being bent. Also inspect the water pump bearings for smooth operation 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 an extra strain on that accessory drive component causing it to vibrate.

Scheme 788

If the drive belt(s) repeatedly falls off the accessory drive pulley(s), this may be caused by a pulley misalignment.

An extra load that is quickly applied or released by an accessory drive component may also cause the drive belt(s) to fall off. Verify that the accessory drive component(s) are operating properly.

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

The number(s) below refer to the step(s) in the diagnostic table.

1. 2. This inspection is to verify the condition of the drive belt(s). Damage may have occurred to the drive belt(s) when the drive belt(s) fell off the pulley. Inspect the drive belt(s) for cuts, tears, sections of ribs missing, or damaged belt plys.
2. 4. Misalignment of the accessory drive pulley(s) may be caused from improper mounting or incorrect installation of a accessory drive component, or the pulley may be 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 removal and installation procedure of that pulley.
3. 5. Inspection of the accessory drive pulley(s) should include inspecting for bends, dents, or other damage that would prevent the drive belt from seating properly in the pulley grooves or on the smooth surface of a pulley when the back side of the drive belt(s) is used to drive the pulley.
4. 6. Accessory drive component brackets that are bent or cracked will also cause the drive belt(s) to fall off.
5. 7. Inspection of the fasteners can eliminate the possibility that a incorrect bolt, nut, spacer, or washer was installed. Missing, loose, or incorrect fasteners may cause pulley misalignment from the accessory drive bracket(s) moving under load. Over tightening the fasteners may cause misalignment of the accessory component bracket(s).

Scheme 789

Excessive wear on a drive belt(s) is usually caused by incorrect installation or the incorrect drive belt(s) for the application.

Minor misalignment of the accessory drive pulley(s) will not cause excessive wear, but will probably cause the drive belt(s) to make a noise or fall off.

Excessive misalignment of the accessory drive pulley(s) will cause excessive wear and may also make the drive belt(s) fall off.

The number(s) below refer to the step(s) in the diagnostic table.

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

Scheme 790

Inspection Procedure

Important: When the engine is operating the drive belt tensioner arm will move. Do not replace the drive belt tensioner because of movement in the drive belt tensioner arm.

Scheme 791

1. Remove the drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Drive Belt Replacement - Air Conditioning»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Move the drive belt tensioner through its full travel. The movement should feel smooth. There should be no binding. The tensioner should return freely.
3. If any binding is observed, replace the drive belt tensioner. Refer to «Drive Belt Tensioner Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Drive Belt Tensioner Replacement - Air Conditioning»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
4. Install the drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Drive Belt Replacement - Air Conditioning»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 792

Scheme 793

1. Remove the air cleaner assembly.
2. Remove the retaining bolt for the coolant recovery reservoir and set the reservoir aside.
3. Install a breaker bar with hex-head socket to the drive belt tensioner bolt.
4. Rotate the drive belt tensioner clockwise in order to relieve tension on the belt.
5. Remove the belt from the pulleys and the drive belt tensioner.
6. Slowly release the tension on the drive belt tensioner.
7. Remove the breaker bar and socket and from the drive belt tensioner bolt.
8. Clean and inspect the belt surfaces of all the pulleys.

Scheme 794

1. Route the drive belt around all the pulleys except the idler pulley.
2. Install the breaker bar with hex-head socket to the belt tensioner bolt.
3. Rotate the belt tensioner clockwise in order to relieve the tension on the tensioner.
4. Install the drive belt under the idler pulley.
5. Slowly release the tension on the belt tensioner.
6. Remove the breaker bar and socket from the belt tensioner bolt.
7. Inspect the drive belt for proper installation and alignment. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Position the coolant recovery reservoir and install the retaining bolt. Tighten Tighten the bolt to 11 N.m (97 lb in).
8. Install the air cleaner assembly.

Scheme 795

Scheme 796

1. Remove the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Raise the vehicle.
3. Install a ratchet into the air conditioning (A/C) belt tensioner adapter opening.
4. Rotate the A/C belt tensioner clockwise in order to relieve tension on the belt.
5. Remove the A/C belt from the pulleys.
6. Slowly release the tension on the A/C belt tensioner.
7. Remove the ratchet from the A/C belt tensioner.
8. Clean and inspect the belt surfaces of all the pulleys.

Scheme 797

Scheme 798

1. Install the A/C belt around the crankshaft balancer.
2. Install a ratchet into the A/C drive belt tensioner adapter opening
3. Rotate the A/C belt tensioner clockwise in order to relieve tension on the tensioner.
4. Install the A/C belt over the idler pulley.
5. Install the A/C belt around the A/C compressor pulley.
6. Slowly release the tension on the A/C belt tensioner.
7. Remove the ratchet from the A/C belt tensioner.
8. Inspect the A/C belt for proper installation and alignment.
9. Install the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
10. Lower the vehicle.

Scheme 799

1. Remove the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the drive belt idler pulley and bolt.

Scheme 800

1. Install the drive belt idler pulley and bolt to the generator bracket. Snug the bolt finger tight.
2. Install the drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) . CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
3. Tighten the drive belt idler pulley bolt. Tighten Tighten the drive belt idler pulley bolt to 50 N.m (37 lb ft).

Scheme 801

1. Remove the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the drive belt tensioner bolts.
3. Remove the drive belt tensioner.

Scheme 802

1. Install the drive belt tensioner.
2. Install the drive belt tensioner bolts. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
3. Tighten the drive belt tensioner bolts. Tighten Tighten the accessory drive belt tensioner bolts to 50 N.m (37 lb ft).
4. Install the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 803

1. Remove the air conditioning (A/C) drive belt. Refer to «Drive Belt Replacement - Air Conditioning»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the A/C belt tensioner bolts.
3. Remove the A/C belt tensioner.

Scheme 804

1. Install the A/C belt tensioner. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the A/C belt tensioner bolts. Tighten Tighten the A/C belt tensioner bolts to 50 N.m (37 lb ft).
3. Install the A/C drive belt. Refer to «Drive Belt Replacement - Air Conditioning»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Engine Mount Inspection

Scheme 805

Scheme 806

1. Raise the vehicle.
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-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) «Engine Mount Replacement - Right»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l)
4. Remove the starter, when checking the right side only. Refer to «STARTER MOTOR REPLACEMENT (4.8L, 5.3L & 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-48l-53l) or «STARTER MOTOR REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-43l) . CAUTION: When raising or supporting the engine for any reason, do not use a jack under the oil pan, any sheet metal, or the crankshaft pulley. Lifting the engine in an unapproved manner may cause component damage.
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.

Removal Procedure

Scheme 807

Scheme 808

Scheme 809

1. Raise and support the vehicle.
2. Remove the tire and wheel. Refer to «TIRE AND WHEEL REMOVAL AND INSTALLATION»(/chevrolet/chevy-express-h2500/2003-2003/remont/wheel-tire-system/#tires-wheels__tire-and-wheel-removal-and-installation) .
3. Remove the front propeller shaft, 4WD vehicles only. Refer to «PROPELLER SHAFT REPLACEMENT - FRONT»(/chevrolet/chevy-express-h2500/2003-2003/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
4. Remove the engine mount to the frame mounting bolts through the wheelwell. CAUTION: When raising or supporting the engine for any reason, do not use a jack under the oil pan, any sheet metal, or crankshaft balancer. Jacking against the oil pan may cause it to crack or break. Important: Raise the engine only enough to permit removal of the engine mount.
5. Using a jack on the square tab at the rear of the engine block and raise the engine, left side shown.
6. Remove the front engine mount to the engine mounting bolts through the wheelwell.
7. Remove the rear engine mount to the engine mounting bolts from under the vehicle.
8. Remove the engine mount from the vehicle.

Scheme 810

Scheme 811

1. Install the engine mount to the vehicle.
2. Install the rear engine mount to the engine mounting bolts from under the vehicle. Do not tighten at this time. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
3. Install the front engine mount to the engine mounting bolts through the wheelwell. Tighten Tighten the engine mount to engine mounting bolts to 50 N.m (37 lb ft)
4. Lower the engine.
5. Install the engine mount to the frame mounting bolts through the wheelwell. Tighten Tighten the engine mount to frame mounting bolts to 60 N.m (44 lb ft)
6. Install the front propeller shaft, 4WD vehicles only. Refer to «PROPELLER SHAFT REPLACEMENT - FRONT»(/chevrolet/chevy-express-h2500/2003-2003/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
7. Install the tire and wheel. Refer to «TIRE AND WHEEL REMOVAL AND INSTALLATION»(/chevrolet/chevy-express-h2500/2003-2003/remont/wheel-tire-system/#tires-wheels__tire-and-wheel-removal-and-installation) .
8. Lower the vehicle.

Scheme 812

Scheme 813

Scheme 814

1. Raise and support the vehicle.
2. Remove the starter. Refer to «STARTER MOTOR REPLACEMENT (4.8L, 5.3L & 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-48l-53l) or «STARTER MOTOR REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-43l) .
3. Remove the right side exhaust manifold. Refer to «EXHAUST MANIFOLD REPLACEMENT - RIGHT (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) or «EXHAUST MANIFOLD REPLACEMENT-RIGHT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) .
4. Remove the engine mount to the frame mounting bolts. CAUTION: When raising or supporting the engine for any reason, do not use a jack under the oil pan, any sheet metal, or crankshaft balancer. Jacking against the oil pan may cause it to crack or break. Important: Raise the engine only enough to permit removal of the engine mount.
5. Using a jack on the square tab at the rear of the engine block and raise the engine, left side shown.
6. Remove the engine mount to the engine mounting bolts.
7. Remove the engine mount from the vehicle.

Scheme 815

Scheme 816

1. Install the engine mount to the vehicle. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the engine mount to the 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 right side exhaust manifold. Refer to «EXHAUST MANIFOLD REPLACEMENT - RIGHT (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) or «EXHAUST MANIFOLD REPLACEMENT-RIGHT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) .
6. Install the starter. Refer to «STARTER MOTOR REPLACEMENT (4.8L, 5.3L & 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-48l-53l) or «STARTER MOTOR REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-43l) .
7. Lower the vehicle.

Scheme 817

1. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim .
2. Remove the positive crankcase ventilation (PCV) tube (1) from the rocker arm cover.
3. Remove the PCV valve (2) from the PCV tube (1).

Scheme 818

1. Install a new PCV valve (2) to the PCV tube (1).
2. Install the PCV tube (1) to the rocker arm cover.
3. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim .

Scheme 819

Scheme 820

1. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim .
2. Remove the positive crankcase ventilation (PCV) tube (1) from the intake manifold and valve rocker arm cover.
3. Remove the PCV valve (2) from the PCV tube (1).
4. Remove the vent hose from the throttle body and the valve rocker arm cover.
5. Replace the hose/tube as necessary.

Scheme 821

Scheme 822

1. Install the vent hose to the throttle body and the valve rocker arm cover.
2. Install the PCV valve (2) to the tube (1).
3. Install the PCV tube (1) to the intake manifold and valve rocker arm cover.
4. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim .

Important: The intake manifold, throttle body, fuel rail, and injectors may be removed as an assembly. If not servicing the individual components, remove the manifold as a complete assembly.

Scheme 823

Scheme 824

Scheme 825

Scheme 826

Scheme 827

Scheme 828

Scheme 829

Scheme 830

Scheme 831

1. Remove the throttle body. Refer to «THROTTLE BODY»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-gasoline) .
2. Remove the oil fill tube. Refer to «Oil Level Indicator and Tube Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
3. Remove the fuel injectors. Refer to «FUEL RAIL & INJECTORS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-gasoline__fuel-rail-injectors) .
4. Disconnect the following electrical connectors: Manifold absolute pressure (MAP) sensor (1) Knock sensor (2) Exhaust gas recirculation (EGR) valve, if equipped
5. Remove the knock sensor harness electrical connector from the intake manifold.
6. Set the electrical harness aside.
7. If equipped, remove the following EGR pipe bolts: Intake manifold (1) Cylinder head (2) Exhaust manifold (3)
8. If equipped, remove the EGR pipe (with valve).
9. If equipped, remove the EGR pipe gasket from the exhaust manifold.
10. Remove the positive crankcase ventilation (PCV) hose (with valve).
11. Remove the MAP sensor (1) from the intake manifold.
12. Remove the accelerator control cable bracket bolts (1).
13. Remove the accelerator control cable bracket (2) from the intake manifold.
14. Remove the evaporative emission (EVAP) purge solenoid vent tube by performing the following: Remove the EVAP tube end (2) from the solenoid (1). Squeeze the EVAP pipe quick connect fitting (3) retainer together. Remove the EVAP tube end (3) from the vapor pipe.
15. Remove the EVAP purge solenoid bolt (2), solenoid (3), and isolator (1) from the intake manifold.
16. Remove the intake manifold bolts.
17. Remove the intake manifold.
18. Remove the intake manifold gaskets (1) from the intake manifold.
19. Discard the old intake manifold gaskets.
20. Clean the gasket surfaces of the EGR pipe and the exhaust manifold, if equipped.

Scheme 832

Scheme 833

Scheme 834

Scheme 835

Scheme 836

Scheme 837

Scheme 838

Scheme 839

Scheme 840

Scheme 841

1. Install new intake manifold gaskets (1) to the intake manifold.
2. Install the intake manifold.
3. Apply a 5 mm (0.20 in) band of threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the intake manifold bolts. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
4. Install the intake manifold bolts. Tighten Tighten the intake manifold bolts a first pass in sequence to 5 N.m (44 lb in). Tighten the intake manifold bolts a final pass in sequence to 10 N.m (89 lb in).
5. Install the EVAP purge solenoid (3), isolator (1), and bolt (2) to the intake manifold. Tighten Tighten the EVAP purge solenoid bolt to 10 N.m (89 lb in).
6. Install the EVAP purge solenoid vent tube to the solenoid (1) and vapor pipe.
7. Install the accelerator control cable bracket (2) to the intake manifold.
8. Install the accelerator control cable bracket bolts (1). Tighten Tighten the accelerator control cable bracket bolts to 10 N.m (89 lb in). Important: Lightly coat the MAP sensor seal with clean engine oil before installing.
9. Install the MAP sensor (1) to the intake manifold.
10. Install the PCV hose (with valve).
11. If equipped, position a new EGR pipe gasket on the exhaust manifold.
12. If equipped, install the EGR pipe (with valve).
13. If equipped, install the following EGR pipe bolts until snug: Intake manifold (1) Cylinder head (2) Exhaust manifold (3)
14. If equipped, tighten the EGR pipe bolts. Tighten Tighten the EGR valve pipe-to-intake manifold bolts to 10 N.m (89 lb in). Tighten the EGR valve pipe-to-cylinder head bolts to 50 N.m (37 lb ft). Tighten the EGR valve pipe-to-exhaust manifold bolts to 30 N.m (22 lb ft).
15. Route the electrical harness into position over the engine.
16. Connect the knock sensor harness electrical connector to the intake manifold.
17. Connect the following electrical connectors. MAP sensor (1) Knock sensor (2) EGR valve, if equipped
18. Install the fuel injectors. Refer to «FUEL RAIL & INJECTORS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-gasoline__fuel-rail-injectors) .
19. Install the oil fill tube. Refer to «Oil Level Indicator and Tube Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
20. Install the throttle body. Refer to «THROTTLE BODY»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-gasoline) .

Scheme 842

Scheme 843

Scheme 844

Scheme 845

1. Remove the intake manifold. Refer to «Intake Manifold Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Gently pry up the rubber covers.
3. Disconnect the knock sensor electrical connectors.
4. Remove the knock sensors.
5. Remove the engine valley cover bolts.
6. Remove the engine valley cover and gasket.
7. Discard the old gasket.
8. Remove the knock sensor oil seals (1) from the cover (2).
9. Clean and inspect the engine valley cover. Refer to «Engine Valley Cover Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-valley-cover-cleaning-and-inspection) .

Installation Procedure

Important: All gasket surfaces should be free of oil or other foreign material during assembly.

Scheme 846

Scheme 847

Scheme 848

Scheme 849

1. Lubricate the NEW knock sensor seals (1) with clean engine oil.
2. Install the knock sensor oil seals (1) into the engine valley cover (2).
3. Install the engine valley cover and a NEW gasket onto the engine block. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
4. Install the engine valley cover bolts. Tighten Tighten the bolts to 25 N.m (18 lb ft).
5. Install the knock sensors. Tighten Tighten the sensors to 20 N.m (15 lb ft).
6. Connect the knock sensor electrical connectors.
7. Push down on the rubber covers.
8. Install the intake manifold. Refer to «Intake Manifold Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 850

Scheme 851

Scheme 852

Scheme 853

Scheme 854

1. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim .
2. Remove the connector position assurance (CPA) lock.
3. Disconnect the main electrical connector (2) to the ignition coil wire harness.
4. Remove the harness clips (1).
5. Reposition the engine harness, if necessary.
6. Remove the spark plug wires from the ignition coils. Twist each plug wire 1/2 turn. Pull only on the boot in order to remove the wire from the ignition coil.
7. Remove the ignition coil bracket studs from the rocker arm cover.
8. Remove the ignition coils and bracket from the rocker arm cover.
9. Remove the positive crankcase ventilation (PCV) hose from the rocker arm cover.
10. Remove the valve rocker arm cover bolts.
11. Remove the valve rocker arm cover.
12. Remove the gasket (1) from the rocker cover.
13. Discard the OLD gasket.

Important

1. All gasket surfaces should be free of oil an/or other foreign material during assembly.
2. DO NOT reuse the valve rocker arm cover gasket.
3. The valve rocker arm cover bolt grommets may be reused.
4. If the PCV valve grommet has been removed from the rocker cover, install a NEW grommet during assembly.

Scheme 855

Scheme 856

Scheme 857

Scheme 858

Scheme 859

1. Install a NEW rocker cover gasket (1) into the groove of the valve rocker arm cover.
2. Install the valve rocker arm cover onto the cylinder head.
3. Install new rocker arm cover grommets, if necessary. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
4. Install the rocker arm cover bolts. Tighten Tighten the valve rocker arm cover bolts to 12 N.m (106 lb in).
5. Install the PCV hose to the rocker arm cover.
6. Apply threadlock GM U.S. P/N 12345382, Canada P/N 10953489, or equivalent to the threads of the bracket bolts.
7. Install the ignition coils and bracket to the rocker arm cover.
8. Install the ignition coil bracket studs to the rocker arm cover. Tighten Tighten the ignition coil bracket studs to 12 N.m (106 lb in).
9. Install the spark plug wires to the ignition coils.
10. Position the engine harness, if necessary.
11. Install the harness clips (1).
12. Connect the main electrical connector (2) to the ignition coil wire harness.
13. Install the CPA lock.
14. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim .

Scheme 860

Scheme 861

Scheme 862

Scheme 863

Scheme 864

1. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim .
2. Remove the upper transmission fill tube.
3. Remove the oil fill tube. Refer to «Oil Level Indicator and Tube Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
4. Disconnect the main electrical connector (1) to the ignition coil wire harness.
5. Remove the harness clips (2).
6. Reposition the engine harness, if necessary.
7. Remove the spark plug wires from the ignition coils. Twist each plug wire 1/2 turn. Pull only on the boot in order to remove the wire from the ignition coil.
8. Remove the ignition coil bracket studs from the rocker arm cover.
9. Remove the ignition coils and bracket from the rocker cover.
10. Remove the vent hose from the valve rocker arm cover.
11. Remove the valve rocker arm cover bolts.
12. Remove the valve rocker arm cover.
13. Remove the gasket (1) from the rocker cover.
14. Discard the OLD gasket.

Important

1. All gasket surfaces should be free of oil or other foreign material during assembly.
2. DO NOT reuse the valve rocker arm cover gasket.
3. The valve rocker arm cover bolt grommets may be reused.

Scheme 865

Scheme 866

Scheme 867

Scheme 868

Scheme 869

1. Install a NEW rocker cover gasket (1) into the valve rocker arm cover.
2. Install the valve rocker arm cover onto the cylinder head.
3. Install new rocker arm cover grommets, if necessary. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
4. Install the rocker arm cover bolts and grommets. Tighten Tighten the valve rocker arm cover bolts to 12 N.m (106 lb in).
5. Install the vent hose to the valve rocker arm cover.
6. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the bracket bolts.
7. Install the ignition coils and bracket to the rocker arm cover.
8. Install the ignition coil bracket studs to the rocker cover. Tighten Tighten the ignition coil bracket studs to 12 N.m (106 lb in).
9. Install the spark plug wires to the ignition coils.
10. Position the engine harness, if necessary.
11. Install the harness clips (2).
12. Connect the main electrical connector (1) feeding the ignition coils.
13. Install the CPA lock.
14. Install the oil fill tube. Refer to «Oil Level Indicator and Tube Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
15. Install the upper transmission fill tube.
16. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim .

Scheme 870

Scheme 871

Scheme 872

1. Remove the valve rocker arm cover. Refer to «Valve Rocker Arm Cover Replacement - Left»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Valve Rocker Arm Cover Replacement - Right»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) . Important: Place the valve rocker arms, pushrods, and pivot support, in a rack so that the can be installed in the same location from which they were removed.
2. Remove the valve rocker arm bolts.
3. Remove the valve rocker arms.
4. Remove the valve rocker arm pivot support.
5. Remove the pushrods.
6. Clean and inspect the valve rocker arms and pushrods. Refer to «Valve Rocker Arm and Push Rods Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__valve-rocker-arm-and-push-rods) .

Important: When reusing the valve train components, always install the components to the original location and position.

Valve lash is net build, no valve adjustment is required.

Scheme 873

Scheme 874

Scheme 875

Scheme 876

1. Lubricate the valve rocker arms and pushrods with clean engine oil.
2. Lubricate the flange of the valve rocker arm bolts with clean engine oil. Lubricate the flange or washer surface of the bolt that will contact the valve rocker arm.
3. Install the valve rocker arm pivot support. Important: Make sure that the pushrods seat properly to the valve lifter sockets.
4. Install the pushrods. Important: Make sure that the pushrods seat properly to the ends of the rocker arms. DO NOT tighten the rocker arm bolts at this time.
5. Install the rocker arms and bolts.
6. Rotate the crankshaft until the number one piston is at top dead center (TDC) of the compression stroke. In this position, cylinder number one rocker arms will be off lobe lift, and the crankshaft sprocket key will be at the 1:30 position. The engine firing order is 1,8,7,2,6,5,4,3. Cylinders 1,3,5 and 7 are the left bank. Cylinder 2,4,6 and 8 are the right bank. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
7. With the engine in the number one firing position, tighten the following valve rocker arm bolts: Tighten Tighten the cylinders 1,2,7 and 8 exhaust valve rocker arm bolts to 30 N.m (22 lb ft). Tighten the cylinders 1,3,4 and 5 intake valve rocker arm bolts to 30 N.m (22 lb ft).
8. Rotate the crankshaft 360 degrees.
9. Tighten the following valve rocker arm bolts: Tighten Tighten the cylinders 3, 4, 5 and 6 exhaust valve rocker arm bolts to 30 N.m (22 lb ft). Tighten the cylinders 2, 6, 7 and 8 intake valve rocker arm bolts to 30 N.m (22 lb ft).
10. Install the valve rocker arm cover. Refer to «Valve Rocker Arm Cover Replacement - Left»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Valve Rocker Arm Cover Replacement - Right»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Valve Stem Oil Seal and Valve Spring Replacement

Tools Required

1. J 22794 Spark Plug Port Adapter
2. J 38606 Valve Spring Compressor
3. J 42078 Valve Stem Oil Seal Installer

Scheme 877

Scheme 878

Scheme 879

Scheme 880

Scheme 881

1. Remove the valve rocker arm. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Disconnect the spark plug wire at the spark plug. Twist each plug wire boot 1/2 turn. Pull only on the boot in order to remove the wire from the spark plug. Important: Remove the spark plugs from the cylinder head with the engine at room temperature.
3. Loosen the spark plug 1 or 2 turns.
4. Brush or air blast away any dirt or debris from around the spark plug.
5. Remove the spark plug.
6. Install J 22794 into the spark plug hole.
7. Attach an air hose to J 22794 .
8. Apply compressed air to J 22794 in order to hold the valves in place.
9. Use J 38606 in order to compress the valve spring.
10. Remove the valve stem keys (2).
11. Carefully release the valve spring tension.
12. Remove the J 38606 .
13. Remove the valve spring cap (3).
14. Remove the valve spring (4).
15. Remove the valve stem oil seal and shim (1,5).

Scheme 882

Scheme 883

Scheme 884

Scheme 885

1. Clean the cylinder head valve spring seat and/or shim area.
2. Lubricate the valve guide and valve stem oil seal with clean engine oil.
3. Install the valve stem oil seal and shim (1,5).
4. Install the valve spring (4).
5. Install the valve spring cap (3).
6. Compress the valve spring using the J 38606 .
7. Install the valve keys. Use grease in order to hold the valve keys in place. Make sure the keys seat properly in the groove of the valve stem. Carefully release the valve spring pressure, making sure the valve keys stay in place. Remove the J 38606 . Tap the end of the valve stem with a plastic faced hammer to seat the keys (if necessary).
8. Remove J 22794 from the spark plug port. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
9. Hand start the spark plug. Tighten Tighten the spark plug to 15 N.m (11 lb ft).
10. Install the spark plug wires at the ignition coil.
11. Install the spark plug wire to the spark plug.
12. Inspect the wires for proper installation: Push sideways on each boot in order to check for proper installation. Reinstall any loose boot.
13. Install the valve rocker arm. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 886

Scheme 887

1. Remove the air cleaner assembly.
2. Remove the retaining bolt for the coolant recovery reservoir and set the reservoir aside.
3. Remove the oil level indicator from the tube.
4. Remove the oil level indicator tube bolt from the oil fill tube retaining bracket.
5. Remove the oil level indicator tube from the lower tube. Important: The O-ring seal may be reused if not cut or damaged.
6. Inspect the O-ring seal for cuts or damage.
7. Remove the O-ring seal from the tube (if required).
8. Remove the lower oil fill tube bolt from the engine block.
9. Remove the lower oil fill tube.

Scheme 888

Scheme 889

Scheme 890

1. Lubricate the O-ring seal with clean engine oil.
2. Install the O-ring seal onto the lower oil level indicator tube.
3. Install the lower oil level indicator tube behind the exhaust manifold.
4. Raise and suitably support the vehicle.
5. Install the lower oil level indicator tube into the block. The tube must be installed with the collar flush to the block.
6. Lower the vehicle. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
7. Install the oil level indicator tube bolt Tighten Tighten the oil level indicator tube bolt to 25 N.m (18 lb ft).
8. Install the upper oil level indicator tube into the lower oil fill tube.
9. Install the upper oil fill tube into the retaining bracket. Tighten Tighten the oil fill tube bolt to 10 N.m (88 lb in).
10. Position the coolant recovery reservoir and install the retaining bolt.
11. Install the air cleaner assembly.

Cylinder Head Replacement - Left

Tools Required

1. J 36660-A Torque Angle Meter
2. J 42385-200 Thread Repair Kit

Scheme 891

Scheme 892

1. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim .
2. Remove the generator bracket. Refer to «GENERATOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/charging-system/#charging-system) .
3. Remove the coolant air bleed pipe. Refer to «COOLANT AIR BLEED PIPE ASSEMBLY REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/chevy-express-h2500/2003-2003/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove the left exhaust manifold. Refer to «EXHAUST MANIFOLD REPLACEMENT - LEFT (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) or «EXHAUST MANIFOLD REPLACEMENT-LEFT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) .
5. Remove the pushrods. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) . Important: The cylinder head bolts are NOT reusable.
6. Remove the cylinder head bolts. CAUTION: After removal, place the cylinder head on two wood blocks to prevent damage.
7. Remove the cylinder head.
8. Remove the cylinder head gasket.
9. Discard the gasket.
10. Discard the cylinder head bolts.
11. Clean and inspect the cylinder head. Refer to «Cylinder Head Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-cleaning-and-inspection) .

Important

1. Do not reuse the cylinder head bolts. Install NEW cylinder head bolts during assembly.
2. Do not use any type of sealant on the cylinder head gasket (unless specified).
3. The cylinder head gaskets must be installed in the proper direction and position.

Scheme 893

Scheme 894

Scheme 895

Scheme 896

Scheme 897

1. Clean the engine block cylinder head bolt holes (if required). Thread repair tool J 42385-107, found in J 42385-200 may be used to clean the threads of old threadlocking material.
2. Use spray cleaner GM U.S. P/N 12346139, P/N 12377981, Canada P/N 10953463, or equivalent into the hole.
3. Clean the cylinder head bolt holes with compressed air.
4. Check the cylinder head locating pins for proper installation. Important: When properly installed, the tab on the left cylinder head gasket will be located left of center or closer to the front of the engine.
5. Install the NEW left cylinder head gasket onto the locating pins.
6. Install the cylinder head onto the locating pins and gasket.
7. Install the NEW cylinder head bolts. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
8. Tighten the cylinder head bolts. Tighten Tighten the M11 cylinder head bolts a first pass in sequence to 30 N.m (22 lb ft). Tighten the M11 cylinder head bolts a second pass in sequence to 90 degrees using J 36660-A . Tighten the M11 cylinder head bolts (1,2,3,4,5,6,7,8) to 90 degrees and the M11 cylinder head bolts (9 and 10) to 50 degrees a final pass in sequence using J 36660-A . Tighten the M8 cylinder head bolts (11,12,13,14,15) to 30 N.m (22 lb ft). Begin with the center bolt (11) and alternating side-to-side, work outward tightening all of the bolts.
9. The cylinder head gasket displacement can be verified by markings visible on the top side of the left gasket locating tab. Some 4.8/5.3L head gaskets may have 53 stamped onto the locating tab. Some 6.0L head gaskets may have 60 stamped onto the locating tab.
10. Install the pushrods. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
11. Install the left exhaust manifold. Refer to «EXHAUST MANIFOLD REPLACEMENT - LEFT (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) or «EXHAUST MANIFOLD REPLACEMENT-LEFT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) .
12. Install the coolant air bleed pipe. Refer to «COOLANT AIR BLEED PIPE ASSEMBLY REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/chevy-express-h2500/2003-2003/remont/cooling-system-mechanical/#engine-cooling-system) .
13. Install the generator bracket. Refer to «GENERATOR»(/chevrolet/chevy-express-h2500/2003-2003/remont/charging-system/#charging-system) .
14. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim .

Cylinder Head Replacement - Right

Tools Required

1. J 36660-A Torque Angle Meter
2. J 42385-200 Thread Repair Kit

Scheme 898

Scheme 899

1. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim .
2. Remove the oil level indicator. Refer to «Oil Level Indicator and Tube Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
3. Remove the coolant air bleed pipe. Refer to «COOLANT AIR BLEED PIPE ASSEMBLY REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/chevy-express-h2500/2003-2003/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove the right exhaust manifold. Refer to «EXHAUST MANIFOLD REPLACEMENT - RIGHT (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) or «EXHAUST MANIFOLD REPLACEMENT-RIGHT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) .
5. Remove the pushrods. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) . Important: The cylinder head bolts are NOT reusable.
6. Remove the cylinder head bolts. CAUTION: After removal, place the cylinder head on two wood blocks to prevent damage.
7. Remove the cylinder head.
8. Remove the cylinder head gasket.
9. Discard the gasket.
10. Discard the cylinder head bolts.
11. Clean and inspect the cylinder head. Refer to «Cylinder Head Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-cleaning-and-inspection) .

Important

1. Do not reuse the cylinder head bolts. Install NEW cylinder head bolts during assembly.
2. Do not use any type of sealant on the cylinder head gasket (unless specified).
3. The cylinder head gaskets must be installed in the proper direction and position.

Scheme 900

Scheme 901

Scheme 902

Scheme 903

Scheme 904

1. Clean the engine block cylinder head bolt holes (if required). Thread repair tool J 42385-107, found in J 42385-200 may be used to clean the threads of old threadlocking material.
2. Use spray cleaner GM U.S. P/N 12346139, P/N 12377981, Canada P/N 10953463, or equivalent into the hole.
3. Clean the cylinder head bolt holes with compressed air.
4. Check the cylinder head locating pins for proper installation. Important: When properly installed, the tab on the right cylinder head gasket will be located right of center or closer to the front of the engine.
5. Install the NEW right cylinder head gasket onto the locating pins.
6. Install the cylinder head onto the locating pins and gasket.
7. Install the NEW cylinder head bolts. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
8. Tighten the cylinder head bolts. Tighten Tighten the M11 cylinder head bolts a first pass in sequence to 30 N.m (22 lb ft). Tighten the M11 cylinder head bolts a second pass in sequence to 90 degrees using J 36660-A . Tighten the M11 cylinder head bolts (1,2,3,4,5,6,7,8) to 90 degrees and the M11 cylinder head bolts (9 and 10) to 50 degrees a final pass in sequence using J 36660-A . Tighten the M8 cylinder head bolts (11,12,13,14,15) to 30 N.m (22 lb ft). Begin with the center bolt (11) and alternating side-to-side, work outward tightening all of the bolts.
9. The cylinder head gasket displacement can be verified by markings visible on the top side of the left gasket locating tab. Some 4.8/5.3L head gaskets may have 53 stamped onto the locating tab. Some 6.0L head gaskets may have 60 stamped onto the locating tab.
10. Install the pushrods. Refer to «Valve Rocker Arm and Push Rod Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
11. Install the right exhaust manifold. Refer to «EXHAUST MANIFOLD REPLACEMENT - RIGHT (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) or «EXHAUST MANIFOLD REPLACEMENT-RIGHT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) .
12. Install the coolant air bleed pipe. Refer to «COOLANT AIR BLEED PIPE ASSEMBLY REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/chevy-express-h2500/2003-2003/remont/cooling-system-mechanical/#engine-cooling-system) .
13. Install the oil level indicator. Refer to «Oil Level Indicator and Tube Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
14. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim .

Valve Lifter Replacement

Tools Required

J 3049-A Valve Lifter Remover

Scheme 905

Scheme 906

Scheme 907

1. Remove the cylinder head and gasket. Refer to «Cylinder Head Replacement - Left»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-replacement-left) or «Cylinder Head Replacement - Right»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-replacement-right) .
2. Remove the valve lifter guide bolts (1).
3. Remove the valve lifters and guide. Important: Some valve lifters may be stuck in their bores because of gum or varnish deposits.
4. Use J 3049-A or equivalent in order to remove the valve lifters (if required).
5. Remove the valve lifters from the guide.
6. Organize or mark the components so that they can be installed in the same location from which they were removed.
7. Clean and inspect the valve lifters. Refer to «Valve Lifters and Guides Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__valve-lifters-and-guides-cleaning-and) .

Important: When reusing valve lifters, install the lifters to their original locations.

Scheme 908

Scheme 909

1. Lubricate the valve lifters and engine block valve lifter bores with clean engine oil.
2. Insert the valve lifters into the lifter guides. Align the flat area on the top of the lifter with the flat area in the lifter guide bore. Push the lifter completely into the guide bore.
3. Install the valve lifters and guide to the engine block. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
4. Install the valve lifter guide bolt (1). Tighten Tighten the valve lifter guide bolt (1) to 12 N.m (106 lb in).
5. Install the cylinder head and gasket. Refer to «Cylinder Head Replacement - Left»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-replacement-left) or «Cylinder Head Replacement - Right»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-replacement-right) .

Crankshaft Balancer Replacement

Tools Required

1. J 41816 Crankshaft Balancer Remover
2. J 41816-2 Crankshaft End Protector
3. J 42386-A Flywheel Holding Tool
4. J 41665 Crankshaft Balancer and Sprocket Installer
5. J 36660-A Torque Angle Meter

Scheme 910

Scheme 911

Scheme 912

1. Remove the air conditioning (A/C) drive belt, if equipped. Refer to «Drive Belt Replacement - Air Conditioning»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the accessory drive belt, if not equipped with A/C. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
3. Remove the fan shroud - lower. Refer to «FAN SHROUD REPLACEMENT»(/chevrolet/chevy-express-h2500/2003-2003/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove the starter motor. Refer to «STARTER MOTOR REPLACEMENT (4.8L, 5.3L & 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-48l-53l) or «STARTER MOTOR REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-43l) . Important: Make sure that the teeth of the J 42386-A mesh with the teeth of the engine flywheel. The crankshaft balancer is balanced as an individual component. It is not necessary to mark the balancer prior to removal. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
5. Install the J 42386-A and bolts. Use one M10-1.5 x 120 mm and one M10-1.5 x 45 mm bolt for proper tool operation. Tighten Tighten the J 42386-A bolts to 50 N.m (37 lb ft).
6. Remove the crankshaft balancer bolt. Do not discard the crankshaft balancer bolt. The balancer bolt will be used during the balancer installation procedure.
7. Use the J 41816 and J 41816-2 in order to remove the crankshaft balancer.
8. Remove the J 41816 and the J 41816-2 from the crankshaft balancer.
9. Clean and inspect the crankshaft balancer. Refer to «Crankshaft Balancer Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Important

1. Make sure that the teeth of J 42386-A mesh with the teeth of the engine flywheel.
2. The used crankshaft balancer bolt will be used only during the first pass of the balancer installation procedure. Install a NEW bolt and tighten as described in the second, third and forth passes of the balancer bolt tightening procedure.
3. The crankshaft balancer installation and bolt tightening involves a four stage tightening process. The first pass ensures that the balancer is installed completely onto the crankshaft. The second, third, and forth passes tighten the new bolt to the proper torque.

Important: The balancer should be positioned onto the end of the crankshaft as straight as possible prior to tool installation.

Scheme 913

Scheme 914

Scheme 915

1. Install the crankshaft balancer onto the end of the crankshaft.
2. Use the J 41665 in order to install the crankshaft balancer. Assemble the threaded rod, nut, washer and installer. Insert the smaller end of the installer into the front of the balancer. Use a wrench and hold the hex end of the threaded rod. Use a second wrench and rotate the installation tool nut clockwise until the balancer is started onto the crankshaft. Remove the tool and reverse the installation tool. Position the larger end of the installer against the front of the balancer. Use a wrench and hold the hex end of the threaded rod. Use a second wrench and rotate the installation tool nut clockwise until the balancer is installed onto the crankshaft. Remove the balancer installation tool.
3. Install the used crankshaft balancer bolt. Tighten Tighten the USED crankshaft balancer bolt to 330 N.m (240 lb ft).
4. Remove the used crankshaft balancer bolt. Important: The nose of the crankshaft should be recessed 2.4-4.48 mm (0.094-0.176 in) into the balancer bore.
5. Measure for a correctly installed balancer. If the balancer is not installed to the proper dimensions, install the J 41665 and repeat the installation procedure.
6. Install a NEW crankshaft balancer bolt. Tighten Tighten the crankshaft balancer bolt a first pass to 50 N.m (37 lb ft). Tighten the crankshaft balancer bolt a second pass to 140 degrees using J 36660-A .
7. Remove the J 42386-A and bolts.
8. Install the starter motor. Refer to «STARTER MOTOR REPLACEMENT (4.8L, 5.3L & 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-48l-53l) or «STARTER MOTOR REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-43l) .
9. Install the fan shroud - lower. Refer to «FAN SHROUD REPLACEMENT»(/chevrolet/chevy-express-h2500/2003-2003/remont/cooling-system-mechanical/#engine-cooling-system) .
10. Install the accessory drive belt (if not equipped with A/C). Refer to «Drive Belt Replacement - Accessory»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
11. Install the A/C drive belt (if equipped). Refer to «Drive Belt Replacement - Air Conditioning»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
12. Perform the crankshaft position (CKP) system variation learn procedure. Refer to «CKP SYSTEM VARIATION LEARN PROCEDURE»(/chevrolet/chevy-express-h2500/2003-2003/remont/testing-diagnostics/#engine-controls-self-diagnostics-48l-53l-60l-gasoline__ckp-system-variation-learn-procedure) .

Crankshaft Front Oil Seal Replacement

Tools Required

J 41478 Crankshaft Front Oil Seal Installer

Scheme 916

1. Remove the crankshaft balancer. Refer to «Crankshaft Balancer Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__crankshaft-balancer-replacement) .
2. Remove the crankshaft oil seal (1) from the front cover.

Important

1. Do not lubricate the oil seal sealing surface.
2. Do not reuse the crankshaft oil seal.

Scheme 917

Scheme 918

1. Lubricate the outer edge of the oil seal (1) with clean engine oil.
2. Lubricate the front cover oil seal bore with clean engine oil.
3. Install the crankshaft front oil seal onto the J 41478 guide.
4. Install the J 41478 threaded rod (with nut, washer, guide, and oil seal) into the end of the crankshaft.
5. Use the J 41478 in order to install the oil seal into the cover bore. Use a wrench and hold the hex on the installer bolt. Use a second wrench and rotate the installer nut clockwise until the seal bottoms in the cover bore. Remove the J 41478 . Inspect the oil seal for proper installation. The oil seal should be installed evenly and completely into the front cover bore.
6. Install the crankshaft balancer. Refer to «Crankshaft Balancer Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__crankshaft-balancer-replacement) .

Engine Front Cover Replacement

Tools Required

J 41476 Front and Rear Cover Alignment (at crankshaft seal area)

Scheme 919

Scheme 920

1. Remove the water pump. Refer to «WATER PUMP REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/chevy-express-h2500/2003-2003/remont/cooling-system-mechanical/#engine-cooling-system) or «WATER PUMP REPLACEMENT (4.3L ENGINE)»(/chevrolet/chevy-express-h2500/2003-2003/remont/cooling-system-mechanical/#engine-cooling-system__water-pump-replacement-43l-engine) .
2. Remove the crankshaft balancer. Refer to «Crankshaft Balancer Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__crankshaft-balancer-replacement) .
3. Remove the oil pan-to-front cover bolts.
4. Remove the front cover bolts.
5. Remove the front cover and gasket.
6. Discard the front cover gasket.
7. Clean and inspect the engine front cover. Refer to «Engine Front Cover Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-front-cover-cleaning-and-inspection) .

Important

1. Do not reuse the crankshaft oil seal or front cover gasket.
2. Do not apply any type of sealant to the front cover gasket (unless specified).
3. The special tool in this procedure is used to properly center the front crankshaft front oil seal. All gasket surfaces should be free of oil or other foreign material during assembly. The crankshaft front oil seal MUST be centered in relation to the crankshaft. An improperly aligned front cover may cause premature front oil seal wear and/or engine oil leaks.

Scheme 921

Scheme 922

Scheme 923

1. Apply a 5 mm (0.20 in) bead of sealant GM U.S. P/N 12378190, or equivalent 20 mm (0.80 in) long to the oil pan to engine block junction.
2. Install the front cover gasket and cover.
3. Install the front cover bolts until snug. Do not overtighten.
4. Install the oil pan-to-front cover bolts until snug. Do not over tighten.
5. Install J 41476 to the front cover.
6. Align the tapered legs of the J 41476 with the machined alignment surfaces on the front cover. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
7. Install the crankshaft balancer bolt until snug. Do not overtighten. Tighten Tighten the oil pan to front cover bolts to 25 N.m (18 lb ft). Tighten the engine front cover bolts to 25 N.m (18 lb ft).
8. Remove the J 41476 .
9. Install a NEW crankshaft front oil seal. Refer to «Crankshaft Front Oil Seal Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__crankshaft-front-oil-seal-replacement) .
10. Install the water pump. Refer to «WATER PUMP REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/chevy-express-h2500/2003-2003/remont/cooling-system-mechanical/#engine-cooling-system) or «WATER PUMP REPLACEMENT (4.3L ENGINE)»(/chevrolet/chevy-express-h2500/2003-2003/remont/cooling-system-mechanical/#engine-cooling-system__water-pump-replacement-43l-engine) .

Crankshaft Rear Oil Seal Replacement

Tools Required

J 41479 Crankshaft Rear Oil Seal Installer

Scheme 924

1. Remove the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the crankshaft rear oil seal (1) from the rear cover.

Important

1. The flywheel spacer (if applicable) must be removed prior to oil seal installation.
2. Do not lubricate the oil seal inside diameter (ID) or the crankshaft surface.
3. Do not reuse the crankshaft rear oil seal.

Scheme 925

Scheme 926

1. Lubricate the outside diameter (OD) of the oil seal (1) with clean engine oil. DO NOT allow oil or other lubricants to contact the seal surface.
2. Lubricate the rear cover oil seal bore with clean engine oil. DO NOT allow oil or other lubricants to contact the crankshaft surface.
3. Install the J 41479 tapered cone (2) and bolts onto the rear of the crankshaft.
4. Tighten the bolts until snug. Do not overtighten.
5. Install the rear oil seal onto the tapered cone (2) and push the seal to the rear cover bore.
6. Thread the J 41479 threaded rod into the tapered cone until the tool (1) contacts the oil seal.
7. Align the oil seal into the tool (1).
8. Rotate the handle of the tool (1) clockwise until the seal enters the rear cover and bottoms into the cover bore.
9. Remove the J 41479 .
10. Install the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Engine Rear Cover Replacement

Tools Required

J 41476 Front and Rear Cover Alignment (at crankshaft seal area)

Scheme 927

Scheme 928

1. Remove the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the oil pan-to-rear cover bolts (1).
3. Remove the rear cover bolts.
4. Remove the rear cover and gasket.
5. Discard the rear cover gasket.
6. Clean and inspect the rear cover. Refer to «Engine Rear Cover Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-rear-cover-cleaning-and-inspection) .

Important

1. Do not reuse the crankshaft oil seal or rear cover gasket.
2. Do not apply any type of sealant to the rear cover gasket (unless specified).
3. The special tool in this procedure is used to properly center the crankshaft rear oil seal.
4. The crankshaft rear oil seal will be installed after the rear cover has been installed and aligned. Install the rear cover without the crankshaft oil seal. All gasket surfaces should be free of oil or other foreign material during assembly. The crankshaft rear oil seal MUST be centered in relation to the crankshaft. An improperly aligned rear cover may cause premature rear oil seal wear and/or engine assembly oil leaks.

Scheme 929

Scheme 930

Scheme 931

Scheme 932

1. Apply a 5 mm (0.20 in) bead of sealant GM U.S. P/N 12378190, or equivalent 20 mm (0.80 in) long to the oil pan to engine block junction.
2. Install the rear cover gasket and cover.
3. Install the rear cover bolts until snug. Do not overtighten.
4. Install the oil pan-to-rear cover bolts (1) until snug. Do not overtighten.
5. Rotate the crankshaft until two opposing flywheel bolt holes are parallel to the oil pan surface. Important: The tapered legs of the alignment tool must enter the rear cover oil seal bore.
6. Install the J 41476 and bolts onto the rear of the crankshaft. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
7. Tighten the J 41476 mounting bolts until snug. Do not overtighten. Tighten Tighten the oil pan-to-rear cover bolts to 12 N.m (106 lb in). Tighten the engine rear cover bolts to 25 N.m (18 lb ft).
8. Remove the J 41476 .
9. Install a NEW crankshaft rear oil seal. Refer to «Crankshaft Rear Oil Seal Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__crankshaft-rear-oil-seal-replacement) .
10. Install the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 933

Scheme 934

1. Drain the engine oil.
2. Remove the oil filter.
3. Remove the oil filter adapter (1).

Scheme 935

Scheme 936

1. Install the oil filter adapter (1). Tighten Tighten the oil filter adapter to 55 N.m (40 lb ft).
2. Install the oil filter.
3. Refill the engine oil.

Scheme 937

Scheme 938

1. Drain the engine oil.
2. Remove the oil filter.
3. Remove the oil filter adapter (1).
4. Remove the oil filter bypass valve (2).

Scheme 939

Scheme 940

1. Install the oil filter bypass valve (2). CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the oil filter adapter (1). Tighten Tighten the oil filter adapter to 55 N.m (40 lb ft).
3. Install the oil filter. Tighten Tighten the oil filter to 30 N.m (22 lb ft).
4. Refill the engine oil.

Scheme 941

1. Drain the engine oil.
2. Remove the oil pan cover bolts (1), cover (2), and gasket (3).
3. Discard the gasket.

Scheme 942

1. Install a new oil pan cover gasket (3), the cover (2) and bolts (1). Tighten Tighten the oil pan cover bolts to 12 N.m (106 lb in).
2. Refill the engine oil.

Scheme 943

Scheme 944

Scheme 945

Scheme 946

Scheme 947

Scheme 948

Scheme 949

Scheme 950

Scheme 951

Scheme 952

Scheme 953

Scheme 954

Scheme 955

Scheme 956

1. If equipped with all wheel drive (AWD), remove the inner axle housing nuts and washers from the bracket.
2. Support the front drive axle with a suitable jack.
3. If equipped with AWD, remove the differential carrier lower mounting bolt and nut.
4. If equipped with AWD, remove the differential carrier upper mounting bolt and nut.
5. Lower the front drive axle.
6. Remove the transmission cover bolt.
7. Remove the crossbar bolts.
8. Remove the crossbar.
9. Remove the transmission cover bolt and cover.
10. Drain the engine oil and remove the engine oil filter.
11. Re-install the drain plug and oil filter until snug.
12. If equipped with the 4L60-E automatic transmission, remove the transmission bolt and stud on the right side.
13. Remove the bottom bolt on the left side.
14. If equipped with the 4L80-E automatic transmission, remove the transmission converter cover bolts.
15. Disconnect the oil level sensor electrical connector (6).
16. Remove the battery cable channel bolt.
17. Slide the channel pin out of the oil pan tab.
18. Remove the positive battery cable clip bolt.
19. Remove the oil pan bolts.
20. Remove the oil pan. Important: DO NOT allow foreign material to enter the oil passages of the oil pan, cap or cover the openings as required.
21. Drill (3) out the oil pan gasket retaining rivets (2), if required.
22. Remove the gasket (1) from the pan.
23. Discard the gasket and rivets.
24. If required, clean and inspect the engine oil pan. Refer to «Oil Pan Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__oil-pan-cleaning-and-inspection) .

Important

1. The alignment of the structural oil pan is critical. The rear bolt hole locations of the oil pan provide mounting points for the transmission bellhousing. To ensure the rigidity of the powertrain and correct transmission alignment, it is important that the rear of the block and the rear of the oil pan must NEVER protrude beyond the engine block and transmission bellhousing plane.
2. Do not reuse the oil pan gasket.
3. It is not necessary to rivet the NEW gasket to the oil pan.

Scheme 957

Scheme 958

Scheme 959

Scheme 960

Scheme 961

Scheme 962

Scheme 963

Scheme 964

Scheme 965

Scheme 966

Scheme 967

Scheme 968

Scheme 969

Scheme 970

Scheme 971

1. Apply a 5 mm (0.20 in) bead of sealant GM P/N United States 12378190, or equivalent 20 mm (0.80 in) long to the engine block. Apply the sealant directly onto the tabs of the front cover gasket that protrudes into the oil pan surface.
2. Apply a 5 mm (0.20 in) bead of sealant GM P/N United States 12378190, or equivalent 20 mm (0.8 in) long to the engine block. Apply the sealant directly onto the tabs of the rear cover gasket that protrudes into the oil pan surface. Important: Be sure to align the oil gallery passages in the oil pan and engine block properly with the oil pan gasket.
3. Pre-assemble the oil pan gasket to the pan. Install the gasket onto the pan. Install the oil pan bolts to the pan and through the gasket.
4. Install the oil pan, gasket and bolts to the engine block.
5. Tighten the oil pan bolts until snug. Do not overtighten.
6. Install the transmission converter cover bolts until snug, if equipped with the 4L80-E automatic transmission.
7. Install the transmission bolt and stud on the right side until snug, If equipped with the 4L60-E automatic transmission. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
8. Install the bottom bolt on the left side until snug. Tighten Tighten the oil pan-to-front cover bolts to 25 N.m (18 lb ft). Tighten the oil pan-to-rear cover bolts to 12 N.m (106 lb in). Tighten the converter cover, and transmission bolts/stud to 50 N.m (37 lb ft).
9. Install the positive battery cable clip bolt. Tighten Tighten the bolt to 9 N.m (80 lb in).
10. Slide the channel pin into the oil pan tab.
11. Install the battery cable channel bolt. Tighten Tighten the bolt to 12 N.m (106 lb in).
12. Connect the oil level sensor electrical connector (6).
13. Install the transmission cover and bolt. Tighten Tighten the bolt to 12 N.m (106 lb in).
14. Install the crossbar.
15. Install the crossbar bolts. Tighten Tighten the bolts to 100 N.m (74 lb ft).
16. Install the transmission cover bolt. Tighten Tighten the bolt to 12 N.m (106 lb in).
17. Raise the front drive axle into position.
18. If equipped with AWD, install the differential carrier upper mounting bolt and nut until snug. Do not tighten at this time.
19. If equipped with AWD, install the differential carrier lower mounting bolt and nut. Tighten Tighten the bolts to 100 N.m (75 lb ft).
20. If equipped with AWD, install the inner axle housing washers and nuts to the bracket. Tighten Tighten the nuts to 100 N.m (75 lb ft).
21. Remove the jack from the front drive axle.
22. Install new engine oil and a new oil filter. Refer to «Engine Oil and Oil Filter Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Engine Oil Pressure Sensor and/or Switch Replacement

Tools Required

J 41712 Oil Pressure Sensor Socket

Scheme 972

Scheme 973

1. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim .
2. Disconnect the oil pressure sensor electrical connector (1).
3. Using J 41712 or equivalent, remove the oil pressure sensor.

Scheme 974

Scheme 975

1. Apply sealant GM P/N 12346004, (Canadian P/N 10953480), or equivalent, to the threads of the oil pressure sensor. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Using J 41712 or equivalent, install the oil pressure sensor. Tighten Tighten the oil pressure sensor to 20 N.m (15 lb ft).
3. Connect the oil pressure sensor electrical connector (1).
4. Install the engine cover. Refer to Interior Trim .

Scheme 976

Scheme 977

1. Drain the engine oil. Refer to «Engine Oil and Oil Filter Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Disconnect the oil level sensor electrical connector (6).
3. Remove the oil level sensor from the oil pan.

Scheme 978

Scheme 979

1. Install the oil level sensor to the oil pan. Tighten Tighten the oil level sensor to 13 N.m (115 lb in).
2. Connect the oil level sensor electrical connector (6).
3. Fill the engine oil. Refer to «Engine Oil and Oil Filter Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 980

Scheme 981

Scheme 982

1. Remove the oil pan. Refer to «Oil Pan Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the engine front cover. Refer to «Engine Front Cover Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-front-cover-replacement) .
3. Remove the oil pump screen bolt and nuts.
4. Remove the oil pump screen with O-ring seal.
5. Remove the O-ring seal from the pump screen.
6. Discard the O-ring seal.
7. Remove the remaining crankshaft oil deflector nuts.
8. Remove the crankshaft oil deflector.
9. Remove the oil pump bolts. Important: Do not allow dirt or debris to enter the oil pump assembly, cap end as necessary.
10. Remove the oil pump.
11. Clean and inspect the oil pump. Refer to «Oil Pump Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__oil-pump-cleaning-and-inspection) .

Scheme 983

Scheme 984

Scheme 985

1. Align the splined surfaces of the crankshaft sprocket and the oil pump drive gear and install the oil pump.
2. Install the oil pump onto the crankshaft sprocket until the pump housing contacts the face of the engine block. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
3. Install the oil pump bolts. Tighten Tighten the oil pump bolts to 25 N.m (18 lb ft).
4. Install the crankshaft oil deflector and nuts until snug.
5. Lubricate a NEW oil pump screen O-ring seal with clean engine oil.
6. Install the NEW O-ring seal onto the oil pump screen. Important: Push the oil pump screen tube completely into the oil pump prior to tightening the bolt. Do not allow the bolt to pull the tube into the pump.
7. Align the oil pump screen mounting brackets with the correct crankshaft bearing cap studs.
8. Install the oil pump screen.
9. Install the oil pump screen bolt and nuts. Tighten Tighten the oil pump screen bolt to 12 N.m (106 lb in). Tighten the crankshaft oil deflector/oil pump screen nuts to 25 N.m (18 lb ft).
10. Install the engine front cover. Refer to «Engine Front Cover Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-front-cover-replacement) .
11. Install the oil pan. Refer to «Oil Pan Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Timing Chain and Sprockets Replacement

Tools Required

1. J 8433 Pulley Puller
2. J 41816-2 Crankshaft End Protector
3. J 41558 Crankshaft Sprocket Remover
4. J 41665 Crankshaft Balancer and Sprocket Installer

Scheme 986

Scheme 987

Scheme 988

Scheme 989

1. Remove the oil pump. Refer to «Oil Pump, Pump Screen and Deflector Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Rotate the crankshaft until the timing marks on the crankshaft and the camshaft sprockets are aligned. CAUTION: Do not turn the crankshaft assembly after the timing chain has been removed in order to prevent damage to the piston assemblies or the valves.
3. Remove the camshaft sprocket bolts.
4. Remove the camshaft sprocket and timing chain.
5. Use the J 8433 , the J 41816-2 and the J 41558 in order to remove the crankshaft sprocket.
6. Remove the crankshaft sprocket.
7. Remove the crankshaft sprocket key, if required.
8. Clean and inspect the timing chain and sprockets. Refer to «Timing Chain and Sprockets Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 990

Scheme 991

Scheme 992

Scheme 993

Scheme 994

Scheme 995

1. Install the key into the crankshaft keyway, if previously removed.
2. Tap the key (1) into the keyway until both ends of the key bottom onto the crankshaft.
3. Install the crankshaft sprocket onto the front of the crankshaft. Align the crankshaft key with the crankshaft sprocket keyway.
4. Use the J 41665 in order to install the crankshaft sprocket. Install the sprocket onto the crankshaft until fully seated against the crankshaft flange.
5. Rotate the crankshaft sprocket until the alignment mark is in the 12 o'clock position. Important: Properly locate the camshaft sprocket locating pin with the camshaft sprocket alignment hole. The sprocket teeth and timing chain must mesh. The camshaft and the crankshaft sprocket alignment marks MUST be aligned properly. Locate the camshaft sprocket alignment mark in the 6 o'clock position.
6. Install the camshaft sprocket and timing chain.
7. If necessary, rotate the camshaft or crankshaft sprockets in order to align the timing marks. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
8. Install the camshaft sprocket bolts. Tighten Tighten the camshaft sprocket bolts to 35 N.m (26 lb ft).
9. Install the oil pump. Refer to «Oil Pump, Pump Screen and Deflector Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 996

Scheme 997

Scheme 998

1. Remove the radiator support. Refer to Radiator Support Replacement in Body Front End .
2. Remove the engine front cover. Refer to «Engine Front Cover Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-front-cover-replacement) .
3. Remove the valve lifters. Refer to «Valve Lifter Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__valve-lifter-replacement) .
4. Remove the camshaft sensor bolt and sensor.
5. Rotate the engine until the timing marks on the crankshaft and camshaft sprockets are aligned. CAUTION: Do not turn the crankshaft assembly after the timing chain has been removed in order to prevent damage to the piston assemblies or the valves.
6. Remove the camshaft sprocket and reposition the timing chain.
7. Remove the camshaft retainer bolts and retainer. CAUTION: All camshaft journals are the same diameter, so care must be used in removing or installing the camshaft to avoid damage to the camshaft bearings.
8. Remove the camshaft. Install three M8-1.25 x 100 mm (M8-1.25 x 4.0 in) bolts to the bolt holes in the front of the camshaft. Using the bolts as a handle, carefully rotate and pull the camshaft out of the engine block. Remove the three bolts from the camshaft.
9. If required, clean and inspect the camshaft and bearings. Refer to «Camshaft and Bearings Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__camshaft-and-bearings-cleaning-and-inspection) .

Important: If camshaft replacement is required, the valve lifters must also be replaced.

Scheme 999

Scheme 1000

Scheme 1001

1. Lubricate the camshaft journals and the bearings with clean engine oil.
2. Install three M8-1.25 x 100 mm (M8-1.25 x 4.0 in) bolts to the bolt holes in the front of the camshaft. CAUTION: All camshaft journals are the same diameter, so care must be used in removing or installing the camshaft to avoid damage to the camshaft bearings.
3. Using the bolts as a handle, carefully install the camshaft into the engine block.
4. Remove the three bolts from the front of the camshaft. Important: Install the retainer plate with the sealing gasket facing the engine block. The gasket surface on the engine block should be clean and free of dirt and/or debris. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
5. Install the camshaft retainer and bolts. Tighten Tighten the camshaft retainer bolts to 25 N.m (18 lb ft).
6. Install the camshaft sprocket and position the timing chain.
7. Install the camshaft sprocket bolts. Tighten Tighten the bolts to 35 N.m (26 lb ft).
8. Inspect the camshaft sensor O-ring seal. If the O-ring seal is not cut or damaged, it may be reused.
9. Lubricate the O-ring seal with clean engine oil.
10. Install the camshaft sensor and bolt. Tighten Tighten the camshaft sensor bolt to 25 N.m (18 lb ft).
11. Install the valve lifters. Refer to «Valve Lifter Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__valve-lifter-replacement) .
12. Install the front cover. Refer to «Engine Front Cover Replacement»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-front-cover-replacement) .
13. Install the radiator support. Refer to Radiator Support Replacement in Body Front End .

Scheme 1002

Scheme 1003

1. Remove the automatic transmission, if equipped. Refer to «TRANSMISSION»(/chevrolet/chevy-express-h2500/2003-2003/remont/automatic-trans/#automatic-transmission-removal-installation) . Important: Note the position and direction of the engine flywheel before removal.
2. Remove the engine flywheel bolts.
3. Remove the automatic transmission engine flywheel.
4. Clean and inspect the engine flywheel. Refer to «Engine Flywheel Cleaning and Inspection»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l) .
5. Install 2 M11x1.5 mm bolts (1) to the threaded holes of the spacer, if applicable.
6. Rotate the bolts clockwise to remove the spacer.
7. Remove the spacer from the rear of the crankshaft, if applicable.

Important

1. The flywheel does not use a locating pin for alignment and will not initially seat against the crankshaft flange or spacer (if applicable), but will be pulled onto the crankshaft by the engine flywheel bolts. This procedure requires a three stage tightening process.
2. Certain applications (4.8L manual transmissions or all 6.0L) require a spacer and longer bolts for proper flywheel position.

Scheme 1004

Scheme 1005

Scheme 1006

1. Install the spacer (if applicable) onto the rear of the crankshaft.
2. Install the automatic transmission engine flywheel to the crankshaft. Important: Longer flywheel bolts must be used on applications using a flywheel spacer.
3. Apply threadlock GM P/N 12345382, (Canadian P/N 10953489), or equivalent to the threads of the flywheel bolts. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
4. Install the engine flywheel bolts. Tighten Tighten the engine flywheel bolts a first pass in sequence to 20 N.m (15 lb ft). Tighten the engine flywheel bolts a second pass in sequence to 50 N.m (37 lb ft). Tighten the engine flywheel bolts a final pass in sequence to 100 N.m (74 lb ft).
5. Install the automatic transmission. Refer to «TRANSMISSION»(/chevrolet/chevy-express-h2500/2003-2003/remont/automatic-trans/#automatic-transmission-removal-installation) .

Engine Replacement

Tools Required

1. J 21366 Converter Holding Strap
2. J 42451-1 Engine Support Adapter

Scheme 1007

Scheme 1008

Scheme 1009

Scheme 1010

Scheme 1011

Scheme 1012

Scheme 1013

Scheme 1014

Scheme 1015

Scheme 1016

Scheme 1017

Scheme 1018

Scheme 1019

Scheme 1020

Scheme 1021

Scheme 1022

Scheme 1023

Scheme 1024

Scheme 1025

Scheme 1026

Scheme 1027

Scheme 1028

Scheme 1029

Scheme 1030

Scheme 1031

Scheme 1032

Scheme 1033

Scheme 1034

1. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim .
2. Remove the air conditioning (AC) compressor. Refer to «COMPRESSOR REPLACEMENT (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__compressor-replacement-48l-53l-60l) or «COMPRESSOR REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__compressor-replacement-43l) .
3. Remove the radiator supports. Refer to Radiator Support Replacement in Body Front End .
4. Reposition the radiator inlet hose clamp at the water pump.
5. Remove the radiator inlet hose from the water pump.
6. Reposition the radiator outlet hose clamp at the water pump.
7. Remove the radiator outlet hose from the water pump.
8. Remove the heater hoses. Refer to «HEATER HOSE REPLACEMENT - INLET»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__heater-hose-replacement-inlet) and «HEATER HOSE REPLACEMENT - OUTLET»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__heater-hose-replacement-outlet) .
9. Unsnap the cruise control cable from the throttle body lever, if equipped.
10. Remove the cruise control cable from the bracket, if equipped.
11. Remove the cruise control cable clip from the sight shield retainer, if equipped.
12. Disconnect the accelerator control cable from the throttle body lever, if required.
13. Remove the accelerator control cable from the bracket, if required.
14. Remove the accelerator control cable from the sight shield retainer, if required.
15. Remove the upper intake manifold sight shield retainer bolts and retainer, if necessary.
16. Disconnect the following electrical connectors: Evaporative emissions (EVAP) canister purge solenoid (1) Generator (3)
17. Remove the harness bracket nut (2) in order to remove the engine harness from the intake manifold.
18. Reposition the vent inlet hose clamp at the throttle body.
19. Remove the radiator vent inlet hose from the throttle body.
20. Remove the generator cable from the generator, perform the following: Slide the boot down revealing the terminal stud. Remove the generator cable nut from the terminal stud. Remove the generator cable.
21. Disconnect the main coil harness (2) and fuel injector electrical connectors on the left side.
22. Disconnect the following electrical connectors: Main coil harness (1) Fuel injectors (2) Electronic throttle control (ETC) (3) Exhaust gas recirculation (EGR) valve (4), if equipped
23. Disconnect the throttle position (TP) sensor and idle air control (IAC) valve electrical connectors.
24. Disconnect the manifold absolute pressure (MAP) sensor (1) and knock sensor (2) electrical connectors.
25. Remove the harness ground bolt.
26. Reposition the harness ground and negative battery cable from the block.
27. Disconnect the following electrical connectors: Coolant temperature sensor (1) Electronic variable orifice switch (2)
28. Remove the harness ground bolt at the right rear of the engine block.
29. Reposition the harness ground, and auxiliary negative battery cable, (if equipped) from the block.
30. Remove the harness ground bolt at the left rear of the engine block.
31. Reposition the harness ground, and engine ground strap from the block.
32. Disconnect the following electrical connectors: Oil pressure sensor (1) Camshaft position (CMP) sensor (2)
33. Unclip all of the engine harness clips from the engine.
34. Remove the EVAP purge solenoid vent tube, perform the following: Remove the EVAP tube end (2) from the solenoid (1). Remove the EVAP tube end (3) from the vapor pipe.
35. Disconnect the fuel pipes. Refer to «QUICK CONNECT FITTINGS»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-gasoline) .
36. Raise the vehicle.
37. Disconnect the following electrical connectors: The crankshaft position (CKP) sensor (1) The engine oil level sensor (6) The coolant heater, if equipped
38. Remove the battery cable channel bolt.
39. Slide the channel pin out of the oil pan tab.
40. Gather all branches of the engine wiring harness and reposition off to the side.
41. Lower the vehicle.
42. Remove the rear power steering pump-to-engine block bolt.
43. Remove the generator bracket mounting bolts.
44. Position the bracket aside.
45. Remove the vacuum brake booster hose.
46. Remove the ignition coil(s) (as required) for the proper fit of the J 42451-1 before lifting the engine. Refer to «IGNITION COIL»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-gasoline) .
47. Remove the left and right exhaust manifolds.
48. Remove the intake manifold. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
49. Install the J 42451-1 to the cylinder heads. Tighten Tighten the M10 engine lift bracket bolts to 50 N.m (37 lb ft).
50. Remove the left and right engine mount-to-engine mount bracket bolts.
51. Raise and suitably support the vehicle.
52. Drain the engine oil.
53. Remove the starter motor. Refer to «STARTER MOTOR REPLACEMENT (4.8L, 5.3L & 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-48l-53l) or «STARTER MOTOR REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-43l) .
54. Remove the catalytic converter. Refer to «CATALYTIC CONVERTER REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) or «CATALYTIC CONVERTER REPLACEMENT (DUAL EXHAUST - RIGHT)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) or «CATALYTIC CONVERTER REPLACEMENT (DUAL EXHAUST - LEFT)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) .
55. Remove the positive battery cable clip bolt and clip.
56. Remove the torque converter bolts.
57. Remove the transmission oil level indicator tube nut.
58. Remove the transmission oil level indicator tube.
59. If equipped with the 4L60-E automatic transmission, remove the transmission bolt and stud on the right side.
60. If equipped with the 4L80-E automatic transmission, remove the transmission converter cover bolts.
61. Remove the automatic transmission bolt/studs, if equipped.
62. Separate the engine from the automatic transmission, if equipped. Install the J 21366 to the transmission in order to hold the torque converter.
63. Lower the vehicle.
64. Install an engine hoist to the J 42451-1 .
65. Install a floor jack under the transmission for support. CAUTION: Use care while moving the engine assembly in order to avoid breaking the MAP sensor locating tabs. Broken MAP sensor tabs may result in decreased engine performance.
66. Remove the engine.
67. Install the engine to an engine stand.
68. Remove the engine hoist.
69. Remove the J 42451-1 from the engine.

Scheme 1035

Scheme 1036

Scheme 1037

Scheme 1038

Scheme 1039

Scheme 1040

Scheme 1041

Scheme 1042

Scheme 1043

Scheme 1044

Scheme 1045

Scheme 1046

Scheme 1047

Scheme 1048

Scheme 1049

Scheme 1050

Scheme 1051

Scheme 1052

Scheme 1053

Scheme 1054

Scheme 1055

Scheme 1056

Scheme 1057

Scheme 1058

Scheme 1059

Scheme 1060

Scheme 1061

1. Install the J 42451-1 to the engine. Tighten Tighten the M10 engine lift bracket bolts to 50 N.m (37 lb ft).
2. Install an engine hoist to the J 42451-1 .
3. Remove the engine from the engine stand.
4. Install the engine to the vehicle.
5. Align the engine and transmission.
6. Install the left and right engine mount-to-engine mount bracket bolts. Tighten Tighten the engine mount-to-engine mount bracket bolts to 65 N.m (48 lb ft).
7. Install the upper transmission bolts until snug.
8. Remove the floor jack from under the transmission.
9. Remove the engine hoist.
10. Remove the J 42451-1 from the engine.
11. Install the left and right exhaust manifolds.
12. Install the intake manifold. Refer to «Intake Manifold Installation»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__intake-manifold-installation) .
13. Install the ignition coil(s) and the spark plug wire(s). Refer to «IGNITION COIL»(/chevrolet/chevy-express-h2500/2003-2003/remont/removal-installation/#engine-controls-removal-installation-gasoline) .
14. Raise the vehicle.
15. Remove the J 21366 from the transmission
16. Install the automatic transmission bolt/studs, if equipped.
17. If equipped with the 4L80-E automatic transmission, install the transmission converter cover bolts. Tighten Tighten the transmission converter bolts to 33 N.m (24 lb ft).
18. If equipped with the 4L60-E automatic transmission, install the transmission bolt and stud on the right side. Tighten Tighten the automatic transmission bolts/studs to 50 N.m (37 lb ft).
19. Install the automatic transmission oil level indicator tube, if equipped.
20. Install the automatic transmission oil level indicator tube nut, if equipped. Tighten Tighten the automatic transmission oil level indicator tube nut to 18 N.m (13 lb ft).
21. Install the torque converter bolts, if equipped. Tighten If equipped with the 4L60-E, tighten the torque converter bolts to 63 N.m (37 lb ft). If equipped with the 4L80-E, tighten the torque converter bolts to 60 N.m (44 lb ft).
22. Install the positive battery cable clip and bolt. Tighten Tighten the positive battery cable clip bolt to 9 N.m (80 lb in).
23. Install the catalytic converter. Refer to «CATALYTIC CONVERTER REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) or «CATALYTIC CONVERTER REPLACEMENT (DUAL EXHAUST - RIGHT)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) or «CATALYTIC CONVERTER REPLACEMENT (DUAL EXHAUST - LEFT)»(/chevrolet/chevy-express-h2500/2003-2003/remont/exhaust/#engine-exhaust-system) .
24. Install the starter motor. Refer to «STARTER MOTOR REPLACEMENT (4.8L, 5.3L & 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-48l-53l) or «STARTER MOTOR REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/starter/#starting-system__starter-motor-replacement-43l) .
25. Lower the vehicle.
26. Install the vacuum brake booster hose.
27. Position the generator bracket to the front of the engine.
28. Install the generator bracket bolts until snug.
29. Install the rear power steering pump-to-engine block bolt until snug. Tighten Tighten the rear power steering pump bolt to 50 N.m (37 lb ft). Tighten the generator bracket bolts to 50 N.m (37 lb ft).
30. Route the engine wiring harness to the lower engine area.
31. Raise the vehicle.
32. Slide the channel pin into the oil pan tab.
33. Install the battery cable channel bolt. Tighten Tighten the battery cable channel bolt to 12 N.m (106 lb in).
34. Connect the following electrical connectors: The CKP sensor (1) The engine oil level sensor (6) The coolant heater, if equipped
35. Lower the vehicle.
36. Connect the fuel pipes.
37. Install the EVAP purge solenoid vent tube to the solenoid (1).
38. Install the EVAP tube end (3) to the vapor pipe.
39. Clip all of the engine wiring harness clips to their correct location.
40. Connect the following electrical connectors: Oil pressure sensor (1) CMP sensor (2)
41. Position the harness ground and the engine ground strap to the block.
42. Install the harness ground bolt at the left rear of the engine block.
43. Position the harness ground, and auxiliary negative battery cable (if equipped) to the block.
44. Install the harness ground bolt at the right rear of the engine block. Tighten Tighten the harness ground bolts at the rear of the block to 16 N.m (12 lb ft).
45. Connect the following electrical connectors: Coolant temperature sensor (1) Electronic variable orifice switch (2)
46. Position the harness ground and negative battery cable to the block.
47. Install the harness ground bolt. Tighten Tighten the harness ground bolt to 25 N.m (18 lb ft).
48. Connect the MAP sensor (1) and knock sensor (2) electrical connectors.
49. Connect the TP sensor and IAC valve electrical connectors.
50. Connect the following electrical connectors: Main coil harness (1) Fuel injectors (2) ETC (3) EGR valve (4), if equipped
51. Connect the main coil harness (2) and fuel injector electrical connectors on the left side.
52. Install the generator cable to the generator, perform the following: Install the generator cable. Install the generator cable nut to the terminal stud. Tighten Tighten the generator output terminal nut to 9 N.m (80 lb in). Slide the boot over the terminal stud.
53. Install the radiator vent inlet hose to the throttle body.
54. Position the vent inlet hose clamp at the throttle body.
55. Install the engine wiring harness bracket and nut (2). Tighten Tighten the engine wiring harness bracket nut to 5 N.m (44 lb in).
56. Connect the following electrical connectors: EVAP canister purge solenoid (1) Generator (3) WARNING: In order to avoid possible injury or vehicle damage, always replace the accelerator control cable with a NEW cable whenever you remove the engine from the vehicle. CAUTION: In order to avoid cruise control cable damage, position the cable out of the way while you remove or install the engine. Do not pry or lean against the cruise control cable and do not kink the cable. You must replace a damaged cable.
57. Install a NEW accelerator control cable (if required).
58. Install the cruise control cable clip to the sight shield retainer, if equipped.
59. Install the cruise control cable to the bracket, if equipped.
60. Snap the cruise control cable to the throttle body lever, if equipped.
61. Install the heater hoses. Refer to «HEATER HOSE REPLACEMENT - INLET»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__heater-hose-replacement-inlet) and «HEATER HOSE REPLACEMENT - OUTLET»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__heater-hose-replacement-outlet) .
62. Install the radiator outlet hose to the water pump.
63. Position the radiator outlet hose clamp at the water pump.
64. Install the radiator inlet hose to the water pump.
65. Position the radiator inlet hose clamp at the water pump.
66. Install the radiator supports. Refer to Radiator Support Replacement in Body Front End .
67. Install the A/C compressor. Refer to «COMPRESSOR REPLACEMENT (4.8L, 5.3L, 6.0L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__compressor-replacement-48l-53l-60l) or «COMPRESSOR REPLACEMENT (4.3L)»(/chevrolet/chevy-express-h2500/2003-2003/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning__compressor-replacement-43l) .
68. Fill the crankcase with the proper quantity and grade of engine oil.
69. Perform the CKP system variation learn procedure. Refer to «CKP SYSTEM VARIATION LEARN PROCEDURE»(/chevrolet/chevy-express-h2500/2003-2003/remont/testing-diagnostics/#engine-controls-self-diagnostics-48l-53l-60l-gasoline__ckp-system-variation-learn-procedure) . Important: After an overhaul, the engine should be tested. Use the following procedure after the engine is installed in the vehicle. Disable the ignition system. Crank the engine several times. Listen for any unusual noises or evidence that parts are binding. Enable the ignition system. Start the engine and listen for unusual noises. Check the vehicle oil pressure gage or light and confirm that the engine has acceptable oil pressure. Run the engine speed at about 1000 RPM until the engine has reached normal operating temperature. Listen for sticking lifter and other unusual noises. Inspect for fuel, oil and/or coolant leaks while the engine is running. Perform a final inspection for the proper engine oil and coolant levels.
70. Close the hood.

Important: In order to completely drain the oil from the oil pan internal baffling, the bottom of the oil pan must be level during the oil drain procedure.

Scheme 1062

Scheme 1063

1. Open the hood.
2. Remove the oil fill cap.
3. Raise and suitably support the vehicle.
4. Place a oil drain pan under the oil pan drain plug.
5. Remove the oil pan drain plug.
6. Drain the engine oil.
7. Wipe the excess oil from the drain plug hole and plug.
8. Remove the oil filter from the engine block. Important: Check the old oil filter to ensure that the filter seal is not left on the engine block.
9. Wipe the excess oil from the oil filter mounting.

Scheme 1064

Scheme 1065

1. Lubricate the oil filter seal with clean engine oil. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the oil filter to the engine block. Tighten Tighten the oil filter to 30 N.m (22 lb ft).
3. Install the oil drain plug to the engine block. Tighten Tighten the oil pan drain plug to 25 N.m (18 lb ft).
4. Lower the vehicle.
5. Fill the crankcase with the proper quantity and grade of engine oil.
6. Remove the oil level indicator.
7. Wipe the indicator with a clean cloth.
8. Install the oil level indicator.
9. Remove the oil level indicator in order to check the level.
10. Add oil if necessary.
11. Close the hood.

Draining Fluids and Oil Filter Removal

Tools Required

J 41712 Oil Pressure Switch Socket

Important: In order to completely drain the oil, the bottom of the oil pan must be level during the oil drain procedure.

Scheme 1066

Scheme 1067

Scheme 1068

Scheme 1069

Scheme 1070

Scheme 1071

1. Remove the oil pan drain plug and allow the oil to drain.
2. Remove the engine oil filter.
3. Remove the right rear engine block coolant drain plug and allow the coolant to drain.
4. Remove the left rear engine block coolant drain plug, if applicable, and allow the coolant to drain.
5. Remove the engine block coolant heater, if applicable, and allow the coolant to drain.
6. Use the J 41712 or equivalent in order to remove the oil pressure sensor, if required.

Crankshaft Balancer Removal

Tools Required

1. J 41816 Crankshaft Balancer Remover
2. J 41816-2 Crankshaft End Protector
3. J 42386-A Flywheel Holding Tool

Important

1. Do not use the crankshaft balancer bolt again. Install a NEW crankshaft balancer bolt during final assembly.
2. Ensure the teeth of the flywheel holding tool mesh with the teeth of the engine flywheel.

Scheme 1072

Scheme 1073

Scheme 1074

1. Install the J 42386-A and bolts. Use one M10 - 1.5 x 120 mm and one M10 - 1.5 x 45 mm bolt for proper tool operation. Tighten Tighten the J 42386-A bolts to 50 N.m (37 lb ft).
2. Remove the crankshaft balancer bolt. Do not discard the crankshaft balancer bolt. The balancer bolt will be used during the balancer installation procedure.
3. Use the J 41816 and the J 41816-2 in order to remove the crankshaft balancer.
4. Remove the J 42386-A and bolts.

Engine Flywheel Removal

Important: The flywheel does not use a locating pin for alignment and will not initially seat against the crankshaft flange or spacer, if applicable, but will be pulled onto the crankshaft by the engine flywheel bolts. This procedure requires a 3 stage tightening process.

Scheme 1075

Scheme 1076

Scheme 1077

1. Remove the engine flywheel bolts.
2. Remove the automatic transmission engine flywheel.
3. Install 2 M11x1.5 mm bolts (1) into the threaded holes of the spacer, if applicable.
4. Rotate the bolts clockwise to remove the spacer.
5. Remove the spacer from the rear of the crankshaft, if applicable.

Scheme 1078

1. Remove the oil level indicator from the tube.
2. Remove the oil level indicator tube bolt.
3. Remove the oil level indicator tube from the engine block. Important: Inspect the O-ring seal for cuts or damage. The O-ring seal may be used again if not cut or damaged.
4. Remove the O-ring seal from the tube, if required.

Scheme 1079

Scheme 1080

1. Remove the spark plug wires from the spark plugs. Do not remove the spark plug wires from the ignition coils unless required.
2. Remove the exhaust manifold, bolts, and gasket.
3. Discard the gasket.
4. Remove the heat shield (2) and bolts (3) from the manifold (1), if required.

Exhaust Manifold Removal - Right

Important: Do not remove the exhaust gas recirculation (EGR) valve from the pipe assembly unless service is required, if applicable.

Scheme 1081

Scheme 1082

Scheme 1083

Scheme 1084

Scheme 1085

Scheme 1086

1. Remove the EGR valve, gasket, and bolts.
2. Remove the EGR pipe bolt (1) from the intake manifold.
3. Remove the EGR pipe bolts (1) and gasket from the exhaust manifold.
4. Remove the EGR pipe bolts (3) from the cylinder head.
5. Remove the EGR pipe assembly. With mild force, pull the EGR pipe (2) from the intake manifold.
6. Remove the O-ring seal (1) from the EGR pipe assembly.
7. Discard the exhaust manifold gasket (4) and O-ring seal (1).
8. Remove the spark plug wires from the spark plugs. Do not remove the spark plug wires from the ignition coils unless required.
9. Remove the exhaust manifold, bolts, and gasket.
10. Discard the gasket.
11. Remove the heat shield (2) and bolts (3) from the manifold (1), if required.

Scheme 1087

1. Remove the water pump bolts.
2. Remove the water pump and gaskets.
3. Discard the water pump gaskets.

Throttle Body Removal

Important: The intake manifold, throttle body, fuel injection rail, and fuel injectors may be removed as an assembly. If not servicing the individual components, remove the manifold as a complete assembly.

Scheme 1088

Scheme 1089

1. Remove the electrical wire harness connectors from the throttle body.
2. Remove the engine coolant air bleed hose and clamp.
3. Remove the throttle body nuts.
4. Remove the throttle body.
5. Remove the throttle body gasket (1).
6. Discard the gasket.
7. Remove the throttle body studs, if required.

Fuel Rail and Injectors Removal

Important: The intake manifold, throttle body, fuel injection rail and fuel injectors may be removed as an assembly. If not servicing the individual components, remove the intake manifold as a complete assembly.

Scheme 1090

Scheme 1091

1. Remove the fuel rail stop bracket and bolt, if required.
2. Remove the vacuum hose from the fuel pressure regulator.
3. Loosen the crossover tube-to-right fuel rail retaining bolt.
4. Remove the fuel rail bolts. Important: Do not separate the fuel injectors from the fuel rail unless component service is required. Use cleanliness and care when handling the fuel system components. Do not allow dirt or debris to enter the fuel injectors or fuel rail components, cap ends as necessary.
5. Remove the fuel rail, with injectors, lifting evenly from both sides of the fuel rail until all the injectors have left their bores.

Intake Manifold Removal

Important: The intake manifold, throttle body, fuel injection rail, and fuel injectors may be removed as an assembly. If not servicing the individual components, remove the manifold as a complete assembly.

DO NOT use the intake manifold-to-cylinder head gaskets again.

Scheme 1092

Scheme 1093

Scheme 1094

Scheme 1095

Scheme 1096

Scheme 1097

1. Remove the positive crankcase ventilation (PCV) hose (1) and valve (2).
2. Remove the manifold absolute pressure (MAP) sensor (1), if required.
3. Remove the engine coolant air bleed clamp and hose from the throttle body.
4. Remove the accelerator control cable bracket (2) and bolts (1), if required.
5. Remove the evaporative emission (EVAP) solenoid (3), bolt (2), and isolator (1).
6. Remove the intake manifold bolts.
7. Remove the intake manifold with gaskets.
8. Separate the intake manifold-to-cylinder head gaskets (1) from the manifold.
9. Discard the intake manifold gaskets.

Scheme 1098

Scheme 1099

Scheme 1100

Scheme 1101

1. Remove the engine coolant air bleed pipe bolts (1).
2. Remove the pipe (2) and gaskets (3).
3. Remove the engine coolant air bleed pipe cover bolts (1) and covers (2).
4. Remove the gaskets from the pipe and covers.
5. Discard the gaskets.
6. Remove the hose (1) from the pipe (2).

Scheme 1102

Scheme 1103

Scheme 1104

Scheme 1105

1. Remove the knock sensor wire harness.
2. Remove the knock sensors.
3. Remove the valley cover bolts.
4. Remove the valley cover and gasket.
5. Discard the valley cover gasket.
6. Remove the knock sensor oil seals (1) from the cover (2).

Valve Rocker Arm Cover Removal - Left

Important: Do not remove the ignition coils and bracket from the valve rocker arm cover unless required.

Do not remove the positive crankcase ventilation (PCV) valve grommet from the cover unless service is required.

Scheme 1106

Scheme 1107

Scheme 1108

1. Remove the ignition coil bracket bolts from the rocker arm cover, if required.
2. Remove the ignition coil and bracket assembly from the cover.
3. Remove the valve rocker arm cover bolts.
4. Remove the valve rocker arm cover.
5. Remove the gasket (1) from the cover.
6. Discard the gasket. The bolt grommets may be used again if not damaged.

Valve Rocker Arm Cover Removal - Right

Important: Do not remove the ignition coils from the valve rocker arm cover unless required.

Scheme 1109

Scheme 1110

Scheme 1111

Scheme 1112

1. Remove the ignition coil bracket bolts from the rocker arm cover, if required.
2. Remove the ignition coil and bracket assembly from the cover.
3. Remove the valve rocker arm cover bolts.
4. Remove the valve rocker arm cover.
5. Remove the gasket (1) from the cover.
6. Discard the gasket. The bolt grommets may be used again if not damaged.
7. Remove the oil fill cap from the oil fill tube.
8. Remove the oil fill tube, if required.

Valve Rocker Arm and Push Rod Removal

Important: Place valve rocker arms, valve pushrods, and pivot support, in a rack so that they can be installed in the same location from which they were removed.

Scheme 1113

Scheme 1114

Scheme 1115

1. Remove the valve rocker arm bolts.
2. Remove the valve rocker arms.
3. Remove the valve rocker arm pivot support.
4. Remove the pushrods.

Scheme 1116

Scheme 1117

1. Remove the spark plugs from the cylinder head. Important: The cylinder head bolts can NOT be used again. Install NEW cylinder head bolts during assembly.
2. Remove the cylinder head bolts. CAUTION: After removal, place the cylinder head on two wood blocks to prevent damage.
3. Remove the cylinder head.
4. Remove the gasket.
5. Discard the gasket.
6. Discard the cylinder head bolts.

Scheme 1118

Scheme 1119

1. Remove the spark plugs from the cylinder head. Important: The cylinder head bolts can NOT be used again. Install NEW cylinder head bolts during assembly.
2. Remove the cylinder head bolts. CAUTION: After removal, place the cylinder head on two wood blocks to prevent damage.
3. Remove the cylinder head.
4. Remove the gasket.
5. Discard the gasket.
6. Discard the cylinder head bolts.

Valve Lifter Removal

Tools Required

J 3049-A Valve Lifter Remover

Scheme 1120

Scheme 1121

Scheme 1122

1. Remove the valve lifter guide bolts (1).
2. Remove the valve lifters and guide. Important: Some valve lifters may be stuck in their bores because of gum or varnish deposits.
3. Use the J 3049-A or equivalent in order to remove the valve lifters, if required.
4. Remove the valve lifters from the guide.
5. Organize or mark the components so that they can be installed in the same location from which they were removed. Refer to «Separating Parts»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) .

Scheme 1123

Scheme 1124

Scheme 1125

1. Remove the oil filter.
2. Remove the oil pan cover (2), bolts (1), and gasket (3), if applicable.
3. Discard the gasket.
4. Remove the oil filter fitting (1) and bypass valve (2), if required.

Oil Pan Removal

Important: The original oil pan gasket is retained and aligned to the oil pan by rivets. When installing a new gasket, it is not necessary to install new oil pan gasket rivets.

DO NOT use the oil pan gasket again. When installing the oil pan, install a NEW oil pan gasket.

It is not necessary to remove the oil level sensor prior to oil pan removal. Remove the oil level sensor if service is required.

Scheme 1126

Scheme 1127

Scheme 1128

Scheme 1129

Scheme 1130

Scheme 1131

1. Remove the left closeout cover and bolt.
2. Remove the right closeout cover and bolt.
3. Remove the oil level sensor from the oil pan, if required.
4. Remove the oil pan bolts.
5. Remove the oil pan. Important: DO NOT allow foreign material to enter the oil passages of the oil pan, cap or cover the openings as required. Use care not to gouge, score, or damage the oil pan sealing surface.
6. Drill (3) out the oil pan gasket retaining rivets (2), if required.
7. Remove the gasket (1) from the pan.
8. Discard the gasket and rivets.
9. Remove the oil pan baffle bolts and baffle, if required.

Scheme 1132

Scheme 1133

1. Remove the front cover bolts.
2. Remove the front cover and gasket.
3. Discard the front cover gasket.
4. Remove the crankshaft front oil seal (1) from the cover.

Scheme 1134

Scheme 1135

1. Remove the rear cover bolts.
2. Remove the rear cover and gasket.
3. Discard the rear cover gasket.
4. Remove the crankshaft rear oil seal (1) from the cover.

Scheme 1136

Scheme 1137

Scheme 1138

1. Remove the oil pump screen bolt (4) and nuts (2).
2. Remove the oil pump screen (1) with O-ring seal (3).
3. Remove the O-ring seal from the pump screen.
4. Discard the O-ring seal.
5. Remove the remaining crankshaft oil deflector nuts.
6. Remove the crankshaft oil deflector.
7. Remove the oil pump bolts. Important: Do not allow dirt or debris to enter the oil pump assembly, cap ends as necessary.
8. Remove the oil pump.

Timing Chain and Sprockets Removal

Tools Required

1. J 8433-1 Two Jaw Puller
2. J 41558 Crankshaft Sprocket Remover
3. J 41816-2 Crankshaft End Protector

Scheme 1139

Scheme 1140

Scheme 1141

Scheme 1142

1. Remove the camshaft sprocket bolts.
2. Remove the camshaft sprocket and timing chain.
3. Use the J 8433-1 , the J 41816-2 , and the J 41558 in order to remove the crankshaft sprocket.
4. Remove the crankshaft sprocket.
5. Remove the crankshaft sprocket key, if required.

Scheme 1143

Scheme 1144

Scheme 1145

1. Remove the camshaft sensor bolt and the sensor.
2. Remove the camshaft retainer bolts and the retainer. CAUTION: All camshaft journals are the same diameter, so care must be used in removing or installing the camshaft to avoid damage to the camshaft bearings.
3. Remove the camshaft. Install the 3 M8-1.25 x 100 mm bolts in the camshaft front bolt holes. Using the bolts as a handle, carefully rotate and pull the camshaft out of the engine block. Remove the bolts from the front of the camshaft.

Piston, Connecting Rod, and Bearing Removal

Tools Required

1. J 24270 Cylinder Bore Ridge Reamer
2. J 41556 Connecting Rod Guide

Important: The connecting rods and the bearing caps are NOT interchangeable.

Scheme 1146

Scheme 1147

Scheme 1148

Scheme 1149

Scheme 1150

1. Use the J 24270 in order to remove the cylinder bore ring ridge, if required. 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 or equivalent in order to remove a cylinder ring ridge. Turn the crankshaft so the piston is at the top of the stroke. Remove the cloth. Remove the cutting debris from the cylinder and piston. Important: Using a paint stick or etching tool, place matchmarks or numbers on the connecting rods and the connecting rod caps. The connecting rods and caps MUST be assembled to their original position and direction. A stamping mark on the side of the connecting rod at the crank journal may effect component geometry. Mark the top of the piston to the specific cylinder bore.
2. Remove the connecting rod bolts. Important: Mark, sort, or organize the connecting rod bearings so they may be installed to their original position and location.
3. Remove the connecting rod cap. Refer to «Separating Parts»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) .
4. Install the J 41556 to the connecting rod.
5. Use a hammer and tap lightly on the end of the J 41556 in order to remove the piston and connecting rod assembly from the cylinder bore.
6. Upon removal of the piston and connecting rod assembly, assemble the connecting rod cap and bolts onto the matching connecting rod.

Crankshaft and Bearings Removal

Tools Required

1. J 6125-1B Slide Hammer
2. J 41818 Crankshaft Bearing Cap Remover

Important: The crankshaft bearing caps are machined with the engine block for the proper clearances. Mark or identify each crankshaft bearing cap location and direction before removal. The crankshaft bearing caps MUST be installed to their original position and direction.

Do not use the bearing cap M8 side bolts again.

Remove the bearing cap M8 side bolts prior to cap removal.

Scheme 1151

Scheme 1152

Scheme 1153

Scheme 1154

Scheme 1155

Scheme 1156

Scheme 1157

1. Remove the crankshaft position sensor bolt.
2. Remove the crankshaft position sensor.
3. Remove the crankshaft bearing cap M8 side bolts.
4. Remove the bearing cap M10 bolts and bolt/studs. Note the M10 bolt/stud locations. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
5. Install the J 41818 . Tighten Tighten the J 41818 bolts to 11 N.m (100 lb in).
6. Install the J 6125-1B to the J 41818 in order to remove the crankshaft bearing caps.
7. Remove the bearing caps.
8. Remove the crankshaft. CAUTION: Use care when handling the crankshaft. Avoid damage to the crankshaft position sensor reluctor ring teeth. Nicks, burrs or other damage to the teeth may effect On-Board Diagnostics (OBD) II system performance.
9. Lay the crankshaft onto two wooden V blocks or other protective surface.
10. Remove the crankshaft bearings from the bearing caps and the engine block.
11. Mark, sort, or organize the crankshaft bearings so they may be installed to their original position and location. Refer to «Separating Parts»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) .

Engine Block Plug Removal

Tools Required

J 41712 Oil Pressure Switch Socket

Important: Do not remove the engine block front oil gallery plug unless service is required.

If the front oil gallery plug is removed for service, a NEW oil gallery plug must be installed.

Scheme 1158

Scheme 1159

Scheme 1160

Scheme 1161

Scheme 1162

Scheme 1163

Scheme 1164

Scheme 1165

1. Remove the oil pressure sensor, if not previously removed, using the J 41712 or equivalent.
2. Remove the engine block right rear coolant plug.
3. Remove the engine block coolant heater, if applicable.
4. Remove the engine block left rear coolant plug, if applicable.
5. Remove the engine block left front oil gallery plug.
6. Remove the engine block left rear oil gallery plug.
7. Inspect the block plug sealing washers. If the block plug and heater sealing washers are not damaged, they may be used during assembly.
8. Remove the engine block rear oil gallery plug.
9. Inspect the O-ring seal of the rear oil gallery plug. If the O-ring seal is not cut or damaged, the plug and O-ring seal may be use during assembly. Important: Remove the front oil gallery plug only if service is required. If the front oil gallery plug is removed, a NEW oil gallery plug must be installed.
10. Remove the engine block front oil gallery plug.

Engine Block Cleaning and Inspection

Tools Required

1. J 8087 Cylinder Bore Gage
2. J 42385-100 Thread Repair Kit

1. Clean the following areas: CAUTION: Do not use a caustic solution to clean the aluminum engine block. Important: When cleaning the engine block in a thermal type oven, do not exceed 450°F (232°C). The engine block in the solvent, to remove all sludge, dirt, or debris Refer to «Cleanliness and Care»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__cleanliness-and-care) . WARNING: Wear safety glasses in order to avoid eye damage. Dry the block with compressed air. The gasket surfaces Refer to «Replacing Engine Gaskets»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__replacing-engine-gaskets) . The coolant passages The oil galleries The main bearing caps The engine block cylinder head bolt holes for threadlocking material Thread repair driver tool J 42385-107 may be used to clean the threads of old threadlocking material.
2. Inspect the following areas: The cylinder walls for excessive scratches, gouging, or ring ridge The cylinder bores for excessive ring ridge at the top of the cylinder The coolant jacket for cracks The valve lifter bores for excessive scoring or wear The crankshaft bearing webs for cracks The gasket sealing surfaces for excessive scratches or gouging Refer to «Replacing Engine Gaskets»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__replacing-engine-gaskets) . The oil galleries for restrictions All threaded bolt holes for damage
3. Measure the following areas: The cylinder bores for taper The cylinder bores for excessive ring ridge at the top of the cylinder

Scheme 1166

Scheme 1167

1. Adjust the micrometer to a dimension slightly smaller than the bore size. Adjust the micrometer to 96.0 mm (3.78 in) for 4.8/5.3 liter engines. Adjust the micrometer to 101.62 mm (4.0 in) for 6.0 liter engines.
2. Insert the J 8087 into the micrometer and zero the J 8087 dial.
3. Using a J 8087 , measure the cylinder bore for taper, out-of-round, and oversize. Slide the J 8087 up and down throughout the length of the cylinder bore. Check the bore both parallel and perpendicular to the centerline of the crankshaft at the top, center, and bottom of the bore. A 4.8/5.3 L cylinder bore that measures 96.000-96.018 mm (3.779-3.78 in) may be honed and serviced with a standard size piston. A 6.0 L cylinder bore that measures 101.618-101.636 mm (4.0007-4.0014 in) may be honed and serviced with a standard size piston. A cylinder bore that exceeds the maximum diameter must be serviced with an oversized piston.

Boring Procedure

Important: A 0.5 mm (0.02 in) oversize service piston and a piston ring set are available for the 4.8/5.3/6.0 liter engines.

1. Measure all pistons with a micrometer to determine the cylinder bore diameter.
2. Before you use any type of boring bar, use a fine file and clean the top of the cylinder block removing any dirt or burrs. If you do not inspect the cylinder block, the boring bar may be improperly positioned, tilted, and the cylinder bore could be bored at an incorrect angle.
3. Carefully follow the instructions furnished by the manufacturer regarding use of the equipment.
4. When you bore the cylinders, ensure all the crankshaft bearing caps are in place. Tighten the crankshaft bearing caps to the proper torque in order to avoid distortion of the cylinder bores during final assembly.
5. When you take the final cut with a boring bar, leave 0.03 mm (0.001 in) on the cylinder bore diameter for the finish honing and fit of the piston.

Scheme 1168

1. When honing the cylinders, 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 you remove. Dull, dirty stones cut unevenly and generate excessive heat. Do not hone to final clearance with a coarse or medium-grade stone. Leave sufficient metal so that all stone marks may be removed with fine-grade stones. Perform final honing with a fine-grade stone, honing the cylinder to the proper clearance.
2. During the honing operation, thoroughly clean the cylinder bore. Repeatedly inspect the cylinder bore for fit with the selected piston. All measurements of the piston or the cylinder bore should be made with the components at normal room temperature.
3. When honing a cylinder for fit to an oversize piston, first perform the preliminary honing with a 100 grit stone.
4. Perform final cylinder honing with a 240 grit stone and obtain a 45 degree cross hatch pattern. A 240 grit stone is preferred for final honing. If a 240 grit stone is not available, a 220 grit stone may be used as a substitute.
5. When honing to eliminate taper in the cylinder, make full strokes the complete length of the bore. Repeatedly observe the measurement at the top, the middle, and the bottom of the bore.
6. The finish marks should be clean but not sharp. The finish marks should also be free from imbedded particles and torn or folded metal.
7. By measuring the selected piston at the sizing point and by adding the average of the clearance specification, you can determine the final cylinder honing dimension required.
8. When finished, the reconditioned cylinder bores should have less than or meet the specified out-of-round and taper requirements.
9. After final honing and before the piston is inspected for fit, clean the cylinder bores with hot water and detergent. Scrub the bores with a stiff bristle brush and rinse the bores thoroughly with hot water. Do not allow any abrasive material to remain in the cylinder bores. This abrasive material may cause premature wear of the new piston rings and the cylinder bores. Abrasive material will also contaminate the engine oil and may cause premature wear of the bearings. After washing the cylinder bore, dry the bore with a clean rag.
10. Perform final measurements of the piston and the cylinder bore.
11. Permanently mark the top of the piston for the specific cylinder to which it has been fitted.
12. Apply clean engine oil to each cylinder bore in order to prevent rusting.

Deglazing Procedure

Using a ball type or self centering honing tool, deglaze the cylinder bore lightly. Deglazing should be done only to remove any deposits that may have formed. Use a 240 grit stone of silicone carbide or equivalent material when preforming the deglazing procedure.

A 240 grit stone is preferred for final honing. If a 240 grit stone is not available, a 220 grit stone may be used as a substitute.

Scheme 1169

Crankshaft and Bearings Cleaning and Inspection

Tools Required

1. J 6125-1B Slide Hammer
2. J 7872 Magnetic Base Dial Indicator Set
3. J 36660-A Torque Angle Meter
4. J 41818 Crankshaft Bearing Cap Remover
5. J 43690 Rod Bearing Checking Tool
6. J 43690-100 Rod Bearing Checking Tool - Adapter Kit

Cleaning Procedure

Scheme 1170

1. Clean the crankshaft with solvent.
2. Thoroughly clean all oil passages and inspect for restrictions or burrs. WARNING: Wear safety glasses in order to avoid eye damage.
3. Dry the crankshaft with compressed air.

Important: The reluctor ring teeth should not have imperfections on the rising or falling edges.

Imperfections of the reluctor ring teeth may effect OBD II system performance.

Scheme 1171

Scheme 1172

Scheme 1173

Scheme 1174

Scheme 1175

Scheme 1176

Scheme 1177

Scheme 1178

Scheme 1179

1. Perform a visual inspection of the crankshaft for damage.
2. Inspect the crankshaft position reluctor ring lobes for damage.
3. Inspect the crankshaft journals for wear (1). Journals should be smooth with no signs of scoring, wear, or damage.
4. Inspect the crankshaft journals for grooves or scoring (2).
5. Inspect the crankshaft journals for scratches or wear (3).
6. Inspect the crankshaft journals for pitting or imbedded bearing material (4).
7. Inspect the crankshaft key (1), keyway (2), and threaded hole (3) for damage.
8. Measure the crankpins for the out-of-round.
9. Measure the crankpins for taper.
10. Measure the crankshaft thrust wall width. A crankshaft with a thrust wall width in excess of 26.2 mm (1.0315 in) must be replaced.
11. Measure the crankshaft runout. Use wooden V blocks or a fixture to support the crankshaft on the front and rear journals.
12. Use the J 7872 in order to measure the crankshaft runout at the front and rear intermediate journals.
13. Use the J 7872 in order to measure the runout of the crankshaft rear flange.
14. Use the J 7872 in order to measure the runout of the crankshaft position reluctor ring. Reluctor ring runout should be measured 1.0 mm (0.04 in) below the ring teeth. If the reluctor ring has runout in excess of 0.7 mm (0.028 in), replace the crankshaft.
15. Inspect crankshaft bearings for craters or pockets. Flattened sections on the bearing halves also indicate fatigue.
16. Inspect the crankshaft bearings for excessive scoring or discoloration.
17. Inspect the crankshaft bearings for dirt or debris imbedded into the bearing material.
18. Inspect the crankshaft bearings for improper seating indicated by bright, polished sections of the bearing. If the lower half of the bearing is worn or damaged, both upper and lower halves should be replaced. Generally, if the lower half is suitable for use, the upper half should also be suitable for use.

Measuring Main Bearing Clearance - Gaging Plastic Method

Important: The crankshaft main bearings are a precision insert type. Main bearing caps are machined with the engine block for proper clearance and cannot be shimmed or filed for bearing fit. If the clearances are found to be excessive, new bearings and/or engine block and cap repair or replacement may be required.

Do not rotate the crankshaft while gaging plastic is between the crankshaft journal and the bearing surface.

The crankshaft bearing clearances are critical. Excessive bearing clearance may effect crankshaft position sensor signals and may effect On-Board Diagnostics (OBD) II system operation.

Important: Remove the bearing cap side bolts prior to cap removal.

Scheme 1180

Scheme 1181

Scheme 1182

Scheme 1183

Scheme 1184

Scheme 1185

Scheme 1186

Scheme 1187

Scheme 1188

Scheme 1189

Scheme 1190

1. Remove the bearing cap M8 side bolts.
2. Remove the bearing cap M10 bolts and studs. CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
3. Install the J 41818 to the bearing cap. Tighten Tighten the J 41818 bolts to 11 N.m (100 lb in).
4. Install the J 6125-1 B to the J 41818 in order to remove the bearing cap.
5. Remove the bearing cap and lower bearing.
6. Install gaging plastic onto the crankshaft journal. Install the gaging plastic the full width of crankshaft bearing journal.
7. Install the bearing, bearing cap, bolts and bolt/studs. Tighten Tighten the inner bolts (1-10) a first pass in sequence to 20 N.m (15 lb ft). Tighten the inner bolts (1-10) a final pass in sequence to 80 degrees using the J 36660-A . Tighten the outer bolt/studs (11-20) a first pass in sequence to 20 N.m (15 lb ft). Tighten the outer bolt/studs (11-20) a final pass in sequence to 53 degrees using the J 36660-A . Tighten the side cap bolts to 25 N.m (18 lb ft). Tighten the bolt on one side of the bearing cap and then tighten the bolt on the opposite side of the same bearing cap. Important: Remove the bearing cap side bolts prior to cap removal.
8. Remove the bearing cap M8 side bolts.
9. Remove the bearing cap bolts and bolt/studs.
10. Use the J 41818 and the J 6125-1B in order to remove the bearing cap.
11. Measure the gaging plastic at its widest area using the scale supplied with the plastic gaging kit. If the gaging plastic shows irregularity in the journal exceeding 0.025 mm (0.001 in), remove the crankshaft and measure the journal with a micrometer. If the bearing clearance is greater than 0.065 mm (0.0025 in), select and install an undersized bearing set, and measure the clearance with gaging plastic. If clearance cannot be brought to specifications, replace the crankshaft or grind the crankshaft for use with the next undersized bearing.
12. Measure the crankshaft end play. Thrust the crankshaft forward or rearward. Insert a feeler gage between the center crankshaft bearing and the bearing surface of the crankshaft and measure the bearing clearance. The proper crankshaft end play clearance is 0.04-0.2 mm (0.0015-0.0078 in). If the bearing clearance is not within specifications: Inspect the thrust surfaces for nicks, gouges or raised metal. Minor imperfections may be removed with a fine stone. Replace the thrust bearings and measure the end play. If the correct measurements cannot be obtained, repair the crankshaft thrust surfaces or replace the crankshaft.

Measuring Connecting Rod Bearing Clearance - Gaging Plastic Method

Important: Connecting rod bearings are a precision insert type. Connecting rods are of a powdered metal design and cannot be shimmed or filed for bearing fit. If clearances are found to be excessive, a new bearing and/or connecting rod are required.

Do not rotate the crankshaft while gauging plastic is between the crankshaft journal and the bearing surface.

Scheme 1191

Scheme 1192

Scheme 1193

Scheme 1194

1. Remove the bearing cap, bearing half and bolts.
2. Install the gaging plastic onto the connecting rod bearing journal. Install the gaging plastic the full width of the journal.
3. Install the bearing cap, bearing, and bolts. Tighten Tighten the connecting rod bolts first pass to 20 N.m (15 lb ft). Tighten the connecting rod bolts a final pass to 75 degrees using the J 36660-A . Refer to «Piston, Connecting Rod, and Bearing Installation»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__piston-connecting-rod-and-bearing-installation) .
4. Remove the bearing cap, bearing, and bolts.
5. Measure the gaging plastic at its widest area using the scale supplied with the plastic gaging kit. The connecting rod bearing clearance should be 0.023-0.076 mm (0.0009-0.003 in).

Measuring Connecting Rod Bearing Clearance - Using J 43690/J 43690-100

J 43690 and J 43690-100 have been developed as a more accurate method to measure connecting rod bearing clearances. The instructions below provide an overview of tool set-up and usage. For more detailed information, refer to the tool instruction sheets as supplied by the tool manufacturer.

J 43690 Rod Bearing Checking Tool

Scheme 1195

1. J 43690-20 Swivel Base (1)
2. J 43690-19 Dial Indicator (2)
3. J 43690-2 Base (3)
4. J 43690-5, -6 Handle (4)
5. J 43690-10, -11 Foot (5)
6. 280307 Screw (6)
7. J 43690-1 Pivot Arm Assembly (7)
8. J 43690-3, -7, -8 Screws (8)
9. 280319 Screw (9)
10. 280311 Screw (10)
11. J 43690-17, -18 Adapter (11)
12. 280310 Pin (12)

J 43690-100 Rod Bearing Checking Tool - Adapter Kit

Scheme 1196

1. J 43690-104 Spacer (1)
2. J 43690-105 Retainer Plate (2)
3. 505478 Bolt (3)
4. 511341 Bolt (4)
5. J 43690-106 Retainer Plate (5)
6. J 43690-107 Cap (6)
7. J 43690-102 Foot (7)
8. J 43690-101 Pivot Arm Assembly (8)
9. J 43690-103 Adapter (9)
10. 505439 Adapter (10)

Important: The crankshaft must be secure with no movement or rotation in order to obtain an accurate reading.

Scheme 1197

Scheme 1198

Scheme 1199

1. Rotate the crankshaft until the journal/connecting rod to be measured is in the 12 o'clock position.
2. Remove a bearing cap and bolts (1).
3. Remove the bearing half (2).
4. Insert a piece of paper card stock onto the crankshaft journal.
5. Install the bearing half (2) and cap and bolts (1). Refer to «Fastener Tightening Specifications»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__fastener-tightening-specifications) .
6. Install the following: J 43690-2 (5) J 43690-3 (4) J 43690-101 (2) 280310 (3) J 43690-5 (1)
7. Install the swivel base (1) and dial indicator (2).
8. Adjust per the manufacturers instructions and measure the connecting rod bearing clearance. A connecting rod with a clearance in excess of 0.076 mm (0.003 in) is considered excessive. Service components as required.

Scheme 1200

1. Clean the crankshaft balancer in solvent.
2. Clean the belt grooves of all dirt or debris with a wire brush.
3. Dry the crankshaft balancer with compressed air.
4. Inspect the crankshaft balancer for the following: Worn, grooved, or damaged hub seal surface A crankshaft balancer hub seal surface with excessive scoring, grooves, rust or other damage must be replaced. Minor imperfections on the hub seal surface may be removed with polishing compound or fine grade emery cloth. Important: In order for the belt to track properly, the belt grooves should be free of all dirt or debris. Dirty or damaged belt grooves The balancer belt grooves should be free of any nicks, gouges, or other damage that may not allow the belt to track properly. Minor imperfections may be removed with a fine file. Worn, chunking or deteriorated rubber between the hub and pulley

Scheme 1201

1. Clean the flywheel in solvent.
2. Dry the flywheel with compressed air.
3. Inspect the automatic transmission flywheel for the following conditions: Damaged ring gear teeth Stress cracks around the flywheel-to-crankshaft bolt hole locations Important: Do not attempt to repair the welded areas that retain the ring gear to the flywheel plate. Install a new flywheel. Welded areas that retain the ring gear onto the flywheel for cracking

Piston and Connecting Rod Disassemble

Tools Required

J 24086-C Piston Pin Remover/Installer Set

Scheme 1202

Scheme 1203

Scheme 1204

Scheme 1205

1. Using piston ring pliers, remove the piston rings from the piston.
2. Install fork insert J 24086-920A into fixture J 24086-10.
3. Install the piston and connecting rod assembly onto J 24086-10.
4. Install J 24086-107 into the piston pin and J 24086-88A through the fixture and into J 24086-107. CAUTION: After the installer hub bottoms on the support assembly, do not exceed 35 000 kPa (5,000 psi) pressure, this could cause damage to the tool.
5. Press the piston pin from the piston and connecting rod assembly.
6. The piston and pin are a matched set and are not to be serviced separately. Mark, sort, or organize the piston and the matching piston pin. Refer to «Separating Parts»(/chevrolet/chevy-express-h2500/2003-2003/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) .

Piston and Pin

Important

1. Replace the pistons and the pins that are damaged or show signs of excessive wear.
2. The piston and the pin are a matched set. If service is required, replace the piston and the pin as an assembly.
3. Do not wire brush any part of the piston.

Scheme 1206

Scheme 1207

Scheme 1208