Engine Mechanical - 6.6l (Introduction) Chevrolet Cab & Chassis Silverado 3500

Fastener Tightening Specifications

Fastener Tightening Specifications

Engine Mechanical Specifications

Engine Mechanical Specifications

Sealers, Adhesives, and Lubricants

Sealers, Adhesives, and Lubricants

Connecting Rod Bearings Selection Specifications

Connecting Rod Bearing Grade

Cylinder Head Gasket Selection Specifications

Cylinder Head Gasket Selection Specifications

Crankshaft Bearings Selection Specifications

Crankshaft Bearings Selection Specifications

Valve Clearance Adjustment Specifications

Valve Clearance Adjustment Specifications

Scheme 88

Cylinder Head - Exhaust View

Scheme 89

Cylinder Head - Intake View

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Cylinder Head - Top View

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Cylinder Head - Rear View

Scheme 92

Cylinder Head - Front View

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Intake Manifold - Right Side View

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Intake Manifold - Left Side View

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Oil Cooler

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EGR Cooler - Rear View

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EGR Cooler - Front View

Scheme 98

EGR - Top View

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Thermostat Housing - Top View

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AC Bracket

Scheme 101

Generator Bracket - Front View

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Generator Bracket - Rear View

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Generator Bracket - Side View

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Engine Front Cover - Front View

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Engine Front Cover - Side View

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Engine Front Cover - Bottom View

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Lower Rocker Arm Cover - Top View

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Lower Rocker Arm Cover - Side View

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Upper Rocker Arm Cover - Top View

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Upper Rocker Arm Cover - Bottom View

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Flywheel Housing - Rear View

Scheme 112

Flywheel Housing - Top View

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Flywheel Housing - Bottom View

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Flywheel Housing - Right View

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Flywheel Housing - Left View

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Upper Oil Pan - Bottom View

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Upper Oil Pan - Top View

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Upper Oil Pan - Front View

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Upper Oil Pan - Rear View

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Upper Oil Pan - Side View

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Scheme 127

Scheme 128

The engine identification tag is located on the left side of the block. It is on the front edge of the block.

Diagnostic Starting Point - Engine Mechanical

Begin the system diagnosis by reviewing the Disassembled Views , Engine Component Description , and Lubrication Description in Engine Mechanical - 6.6L Unit Repair Manual. 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 to you 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 in Engine Controls before using the symptom tables, if applicable.
2. Review the system operations in order to familiarize yourself with the system functions. Refer to «Disassembled Views»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction) , «Engine Component Description»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction) , and «Lubrication Description»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction) in the 6.6L section of the Unit Repair Manual, and to the .

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

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the engine.
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/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__base-engine-misfire-without-internal-engine)
2. «Base Engine Misfire with Abnormal Internal Lower Engine Noises»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__base-engine-misfire-with-abnormal-internal)
3. «Base Engine Misfire with Abnormal Valve Train Noise»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__base-engine-misfire-with-abnormal-valve)
4. «Base Engine Misfire with Coolant Consumption»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__base-engine-misfire-with-coolant-consumption)
5. «Base Engine Misfire with Excessive Oil Consumption»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__base-engine-misfire-with-excessive-oil)
6. «Engine Compression Test»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__engine-compression-test)
7. «Engine Noise on Start-Up, but Only Lasting a Few Seconds»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__engine-noise-on-start-up-but-only)
8. «Upper Engine Noise, Regardless of Engine Speed»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__upper-engine-noise-regardless-of-engine)
9. «Lower Engine Noise, Regardless of Engine Speed»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__lower-engine-noise-regardless-of-engine)
10. «Engine Noise Under Load»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__engine-noise-under-load)
11. «Engine Will Not Crank - Crankshaft Will Not Rotate»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__engine-will-not-crank-crankshaft)
12. «Oil Pressure Diagnosis and Testing»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__oil-pressure-diagnosis-and-testing)
13. «Oil Leak Diagnosis»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__oil-leak-diagnosis)
14. «Drive Belt Chirping Diagnosis»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction)
15. «Drive Belt Squeal Diagnosis»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction)
16. «Drive Belt Whine Diagnosis»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction)
17. «Drive Belt Rumbling Diagnosis»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction)
18. «Drive Belt Vibration Diagnosis»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction)
19. «Drive Belt Falls Off Diagnosis»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction)
20. «Drive Belt Excessive Wear Diagnosis»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction)
21. «Drive Belt Tensioner Diagnosis»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__drive-belt-tensioner-diagnosis)

Base Engine Misfire without Internal Engine Noises

Base Engine Misfire without Internal Engine Noises

Base Engine Misfire with Abnormal Internal Lower Engine Noises

Base Engine Misfire with Abnormal Internal Lower Engine Noises

Base Engine Misfire with Abnormal Valve Train Noise

Base Engine Misfire with Abnormal Valve Train Noise

Base Engine Misfire with Coolant Consumption

Base Engine Misfire with Coolant Consumption

Base Engine Misfire with Excessive Oil Consumption

Base Engine Misfire with Excessive Oil Consumption

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

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

Upper Engine Noise, Regardless of Engine Speed

Upper Engine Noise, Regardless of Engine Speed

Lower Engine Noise, Regardless of Engine Speed

Lower Engine Noise, Regardless of Engine Speed

Engine Noise Under Load

Engine Noise Under Load

Engine Will Not Crank - Crankshaft Will Not Rotate

Engine Will Not Crank - Crankshaft Will Not Rotate

Coolant in Combustion Chamber

Coolant in Combustion Chamber

Coolant in Engine Oil

Coolant in Engine Oil

Fuel in Engine Oil

Definition: If fuel is suspected of leaking into the crankcase, the following procedure should be performed to verify the condition.

1. Remove the oil level indicator and allow oil to drop onto a clean white paper towel.
2. If the oil is diluted with fuel, it will become apparent as the towel wicks the fuel away from the drop of oil on the towel. The fuel will expand out in a ring around the oil droplet.
3. If fuel dilution is apparent, refer to «Fuel Leaks»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-66l-troubleshooting-diagnosis__fuel-leaks) in engine controls, for diagnosis and repair. Inspect the vehicle for aftermarket performance accessories that may cause damage to the injection pump. After repairs are completed, perform the test again to verify the condition is corrected.
4. If no fuel dilution is present, verify the oil level and correct as needed.

Turbocharger Whine Noise

Turbocharger Whine Noise

Turbocharger Hissing Noise

Turbocharger Hissing Noise

Turbocharger Oil Leak From Compressor Seal

Turbocharger Oil Leak From Compressor Seal

Turbocharger Oil Leak From Turbine Seal

Turbocharger Oil Leak From Turbine Seal

Turbocharger Lack of Oil Supply

Turbocharger Lack of Oil Supply

Engine Compression Test

Tools Required

1. J 26999 Compression Gage. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__special-tools) .
2. J 26999-20 Compression Gage Adapter. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__special-tools) .
3. J 43244 Relay Puller Pliers

1. Ensure that the vehicle's batteries are in good condition, and fully charged.
2. Operate the vehicle until the engine is at normal operating temperature.
3. Shut off engine.
4. Disable fuel delivery system, by removing the IGN 1 relay with J 43244 .
5. Disconnect glow plug nut; remove all 8 glow plugs. All 8 glow plugs must be removed from the engine during each cylinder test to obtain valid test results.
6. Prior to taking a compression reading, verify the cranking speed is greater than 140 RPM. If the cranking speed is below 140 RPM, repair the slow cranking speed condition before continuing with the compression test. Refer to «Engine Cranks Slowly»(ref-197377-S15604229122005101100000) in Engine Electrical.
7. Install the J 26999-20 in the glow plug hole for the cylinder that is being checked. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__special-tools) .
8. Connect the J 26999 to the . See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__special-tools) . J 26999-20 . See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__special-tools) .
9. Using the vehicle's starter motor, rotate or crank the engine for 6 compression strokes, puffs, for the cylinder being tested.
10. Observe the J 26999 and note the reading as the compression test is being performed. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__special-tools) . A normal cylinder reading will be indicated if compression builds up quickly and evenly to the specified level. An abnormal reading will be indicated if compression is low on the first compression stroke, starts increasing on the following compression strokes but does not reach the specified level.
11. Record the compression reading for the cylinder just tested.
12. Disconnect the J 26999 from the. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__special-tools) . J 26999-20 and remove adapter from the glow plug hole. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__special-tools) .
13. Repeat steps 8 through 13 for all remaining cylinders. All 8 cylinders must be tested to obtain valid test results. Record the readings.
14. The minimum compression in any one cylinder is 2069 kPa (300 psi). There should not be more than 345 kPa (50 psi) difference between a suspect cylinder and the average compression of all 8 cylinders. 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 builds up with the following strokes but does not reach normal. Valves Leaking - Compression is low on the first stroke. Compression usually does not build up on the following strokes.

Cylinder Leakage Test

Tools Required

1. J 35667-A Cylinder Head Leakdown Tester
2. J 35667-9 Cylinder Head Leakdown Adapter. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__special-tools) .

1. Disconnect the battery ground negative cable.
2. Remove the glow plugs.
3. Rotate the crankshaft to place the piston in the cylinder being tested at Top Dead Center (TDC) of the compression stroke.
4. Install J 35667-9 and. See «Special Tools»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-introduction__special-tools) . J 35667-A .
5. Apply shop air pressure to 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 sounds at the intake manifold tube, may indicate a worn, stuck or burnt intake valve, broken valve spring, incorrect valve lash or damaged valve train components. Air leakage sounds at the exhaust system tailpipe may indicate a worn, burnt, or stuck exhaust valve, broken valve spring, incorrect valve lash or damaged valve train components. Air leakage sounds from the crankcase, oil level indicator tube, or oil fill tube may indicate worn piston rings, a damaged piston, a worn or scored cylinder bore, a damaged engine block or a damaged cylinder head. Air bubbles in the cooling system may indicate a damaged cylinder head or gasket.
7. Perform the leakage test on the remaining cylinders and record the values.

Oil Consumption Diagnosis

Oil Consumption Diagnosis

Oil Pressure Diagnosis and Testing

Oil Pressure Diagnosis and Testing

Oil Leak Diagnosis

Oil Leak Diagnosis

Crankcase Ventilation System Inspection/Diagnosis

Crankcase Ventilation System Inspection/Diagnosis

Diagnostic Aids

If a chirping noise occurs during engine shutdown, this is considered normal and is due to the engine's high compression. The chirping noise may be intermittent due to moisture on the drive belt or the accessory drive pulleys. In order to duplicate the customer's concern, it may be necessary to spray a small amount of water onto the drive belt. If spraying water onto the drive belt duplicates the symptom, cleaning the accessory belt pulleys may be the most probable solution.

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

If a chirping noise occurs during engine shutdown, this is considered normal and is due to the engine's high compression.

Test Description

The numbers below refer to the step numbers on 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 further with this table.
2. 3: The noise may be an internal engine noise. Remove the drive belt and operate the engine for a few seconds, this will verify if the chirping noise is related to the drive belt or not. With the drive belt removed the cooling fan will not operate and the engine may overheat. Also, DTCs may set when the engine is operated with the drive belt removed.
3. 4: Inspect the drive belt 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 pulleys 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 pulley using a straight edge in the pulley grooves across 2 or 3 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 pulleys should include inspecting for bends, dents, or other damage to the pulleys that would prevent the drive belt 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 when it is not damaged or there is not excessive pilling will only be a temporary repair.

Drive Belt Chirping Diagnosis

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

If the squeal is intermittent, verify that it is not the accessory drive components 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 steps 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 with this table
2. 3: The squeal may be an internal engine noise. Remove the drive belt and operate the engine for a few seconds, this will verify if the squealing noise is related to the drive belt or an accessory drive component. With the drive belt removed the cooling fan will not be operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt removed.
3. 4: This test is to verify that an accessory drive components does not have a seized bearing. With the belt removed, test the bearings in the accessory drive components for smooth operation. Also test the accessory drive components with the engine operating by varying the load on the accessory drive components to verify that the components is operating properly.
4. 5: This test is to verify that the drive belt tensioner is operating properly. If the drive belt tensioner is not operating properly, proper belt tension may not be achieved to keep the drive belt from slipping which could cause a squealing noise.
5. 6: This test is to verify that the drive belt is not too long, which would prevent the drive belt tensioner from operating properly. Also if the incorrect length drive belt 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 pulleys 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 2 or 3 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 pulleys to verify that they are the correct diameter or width. Using a known good vehicle, compare the accessory drive pulleys.

Drive Belt Squeal Diagnosis

The drive belt will not cause the whine.

If the whine is intermittent, verify that it is not the accessory drive components 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 numbers below refer to the steps in the diagnostic table.

1. 3: This test is to verify that the whine is being caused by the accessory drive components. Remove the drive belt 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 removed the cooling fan will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt removed.
2. 4: The inspection should include checking the drive belt tensioner and the drive belt idler pulley bearings. The drive belt 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 replacement procedure.

Drive Belt Whine Diagnosis

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

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

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

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

1. 2: This test is to verify that the symptom is present during diagnosing. Other vehicle components may cause a similar symptom.
2. 3: This test is to verify that the drive belt is causing the rumbling. Rumbling may be confused with an internal engine noise due to the similarity in the description. Operate the engine for a few seconds, this will verify if the rumbling noise is related to the drive belt or not. With the drive belt removed the cooling fan will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt removed.
3. 4: Inspect the drive belt to ensure that the drive belt is not the cause of the noise. Small cracks across the ribs of the drive belt will not cause the noise. Belt separation is identified by the plys of the belt separating, 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 does not have a smooth surface for proper operation.

Drive Belt Rumbling Diagnosis

The accessory drive components can 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 numbers below refer to the steps 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 or accessory drive components may be causing the vibration. Remove the drive belt and operate the engine for a few seconds, this will verify if the vibration is related to the drive belt or not. With the drive belt 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 removed.
3. 4: The drive belt may cause a vibration. While the drive belt is removed this is the best time to inspect the condition of the drive belt.
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.

Drive Belt Vibration Diagnosis

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

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

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

The numbers below refer to the steps in the diagnostic table.

1. 2: This inspection is to verify the condition of the drive belt. Damage may of occurred to the drive belt when the drive belt fell off. Inspect the drive belt for cuts, tears, sections of ribs missing, or damaged belt plys.
2. 4: Misalignment of the accessory drive pulleys 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 pulley using a straight edge in the pulley grooves across 2 or 3 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 pulleys should include inspecting for bends, dents, or other damage to the pulleys 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 is used to drive the pulley.
4. 6: Accessory drive component brackets that are bent or cracked will also cause the drive belt 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 brackets moving under load. Over tightening the fasteners may cause misalignment of the accessory component brackets.

Drive Belt Falls Off Diagnosis

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

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

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

The numbers below refer to the steps in the diagnostic table.

1. 2: This inspection is to verify the drive belt is correctly installed on all of the accessory drive pulleys. Wear on the drive belt may be caused by mis-positioning the drive belt by one groove on a pulleys.
2. 3: The installation of a drive belt that is too wide or too narrow will cause wear on the drive belt. The drive belt ribs should match all of the grooves on the pulleys.
3. 4: This inspection is to verify the drive belt 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 should not come in contact with an engine or a body component when snapping the throttle.

Drive Belt Excessive Wear Diagnosis

Drive Belt Tensioner Diagnosis

1. Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) .
2. Position a 3/8-inch drive breaker bar into the drive belt tensioner opening and rotate the tensioner counterclockwise.
3. Move the drive belt tensioner through its full travel. The movement should feel smooth There should be no binding The tensioner should return freely
4. If any binding is observed, replace the drive belt tensioner. Refer to «Drive Belt Tensioner Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) .
5. Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/mechanical/#engine-mechanical-66l-repair-instructions-1-of-4) .

Crankcase Ventilation System Description

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

The primary control is through the crankcase depression regulator valve (1), which meters the flow at a rate depending on the crankcase pressure.

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

Drive Belt System Description

The drive belt system consists of the following components

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

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

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

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

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

Scheme 129

The engine block utilizes a deep skirt design for increased rigidity. The cylinders are positioned in a 90 degree "V" orientation with the number one cylinder being the right front. The block is induction hardened for increased durability. The crankshaft bearing caps are cross-bolted to enhance structural rigidity.

Upper Oil Pan

A single piece cast aluminum upper oil pan contributes to crankshaft and block rigidity while reducing overall weight.

Crankshaft

The crankshaft is a nitride hardened steel design with five main bearings. Crankshaft thrust is controlled by the number 5 bearing.

Connecting Rods

The connecting rods are one-piece hot forged steel. The connecting rods and caps are of a fractured split design to improve durability and reduce internal friction. The connecting rod small end is tapered cut for reduced weight and improved durability.

Pistons

The pistons are a full-floating design. The piston pins are a slip fit in the bronze bushed connecting rod and are retained in the piston by round wire retainers. The pistons have a piston cooling oil channel cast inside of the piston. These cooling oil channels utilize an oil jet located at the bottom of the cylinder bore to direct oil into the piston channel. There are two compression rings and one oil control ring. There is a groove machined into the pistons between the first and second compression rings. This groove reduces compression ring leakage by providing an empty space for expanding gases, reducing the combustion gas pressure on the second compression ring.

Cylinder Heads

The cylinder heads are made of aluminum for lighter weight and rapid heat dissipation. There are 4 valves per cylinder and the ports are of a high swirl design for improved combustion. The cylinder head gaskets consist of an all steel laminated construction.

Valve Train

The engine utilizes a mechanical roller lifter for valve operation. The shaft mounted rocker arms have roller tips for reduced friction and wear. One rocker arm operates two valves simultaneously through a valve bridge.

Fuel System

The fuel system is of a direct injection fuel rail design. A high pressure pump mounted within the valley is gear driven directly from the camshaft. This pump provides a continuous and constant high pressure fuel supply to the fuel rails. The electronically controlled fuel injectors receive their fuel supply from these fuel rails. The fuel injection control utilizes a pilot injection method to reduce the combustion noise that is common in traditional diesel engines. The pilot injection method reduces noise by supplying a small amount of fuel to the cylinder just before the normal combustion timing.

Fuel Injection Control Module

The fuel injection control module is mounted on the right front valve rocker arm cover. It is fuel cooled.

Turbocharger

The turbocharger is water cooled for improved durability.

Oil Cooler

The oil cooler lowers engine temperature by cooling the oil with engine coolant. Engine coolant is directed from the water pump to the oil cooler by a coolant tube. The oil filter attaches directly to the oil cooler.

Oil Pump

The oil pump is gear driven directly from the crankshaft. The oil pump drive gear is a slip fit to the crankshaft.

Water Pump

The water pump is gear driven for improved reliability.

Engine Covers

There is a front engine cover and a flywheel housing, both are made of aluminum. The full bell flywheel housing is cross bolted to the upper oil pan. The flywheel housing also supplies a crossover passage for engine coolant. The front engine cover houses the gear train and provides a mounting surface for the cooling fan pulley assembly.

Scheme 130

Engine lubrication is supplied by a gear type oil pump assembly. The pump is mounted on the front of the engine block and driven by the oil pump drive gear on the crankshaft. The pump gears rotate and draw oil from the oil pan sump through a pick-up screen and pipe. The oil is pressurized as it passes through the pump and is sent through the engine block oil galleries. Contained within the oil pump assembly is a safety relief valve that eliminates over pressurization. Pressurized oil is directed through the sub oil gallery (5) to the full flow oil filter where harmful contaminants are removed. Two bypass valves are incorporated into the oil cooler assembly which will permit oil flow in the event the filter or the oil cooler become restricted.

The oil is directed to the main oil gallery (4), and from the main oil gallery it flows to the piston cooling channel left bank (3), and the sub oil gallery (6) on the right bank. The sub oil gallery on the right bank supplies oil to the right bank piston cooling channel (1). Located in the front cover at the sub oil gallery (6) is an oil pressure relief valve which regulates oil pressure within operating range.

Oil flows from the main gallery (4) to the vertical crankshaft/camshaft bearing galleries (2). From the crankshaft/camshaft bearing galleries (2), the oil flows to both the camshaft bearings and the crankshaft main bearings. Oil flows from the crankshaft main bearings to the connecting rod big end.

Oil flows from the crankshaft/camshaft bearing galleries (2) to the number 1 camshaft bearing (7), where it splash lubricates the fuel injection pump gear.

Oil flows from the crankshaft/camshaft bearing galleries (2) to the number 2 and 5 camshaft bearings (8).

Oil flows from the crankshaft/camshaft bearing galleries (2) to the number 3 camshaft bearing (9), where it exits to both cylinder heads and enters the hollow rocker arm shafts. Oil flows through the rocker arm shafts and rocker arms where it lubricates the upper valve train components. Oil also flows through the rocker arms, through the passage in the valve adjusting screw, and into the hollow pushrods where it is directed to the valve lifters.

Oil flows from the crankshaft/camshaft bearing galleries (2) to the number 4 camshaft (10), where it exits into the turbocharger oil supply line to lubricate the turbocharger. Oil exiting the turbocharger is routed through the turbocharger oil return pipe and into the flywheel housing.

Cleanliness and Care

An automobile engine is a combination of many of the following surfaces

1. Machined
2. Honed
3. Polished
4. Lapped

The tolerances of these surfaces are measured in the ten-thousandths of an inch. When you service any internal engine part, cleanliness and care are important. Apply a liberal coating of engine oil to the friction areas during assembly in order to protect and lubricate the surfaces on initial operation. Throughout this section, practice proper cleaning and protection procedures to the machined surfaces and to the friction areas.

Note. Engine damage may result if an abrasive paper, pad, or motorized wire brush is used to clean any engine gasket surfaces.

Whenever you remove the valve train components, keep the components in order. Follow this procedure in order to install the components in the same locations and with the same mating surfaces as when removed.

Disconnect the negative battery cables before you perform any major work on the engine. For more information on the disconnection of the battery, refer to Engine Electrical.

Separating Parts

Separate, mark, or organize the following components

1. Piston and the piston pin
2. Piston to the specific cylinder bore
3. Piston rings to the piston
4. Connecting rod to the crankshaft journal
5. Connecting rod to the bearing cap A paint stick or etching/engraving type tool are recommended. Stamping the connecting rod or cap near the bearing bore may affect component geometry.
6. Crankshaft main and connecting rod bearings
7. Camshaft and valve lifters
8. Valve lifters, guides, pushrods, pivot supports and rocker arms
9. Valve to the valve guide
10. Valve spring and shim to the cylinder head location
11. Engine block main bearing cap location and direction
12. Oil pump drive and driven gears

Gasket Reuse and Applying Sealant

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

Separating Components

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

Sealant Types

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

1. Aerobic sealant (Room Temperature Vulcanizing (RTV))
2. Anaerobic sealant, which include the following: Gasket eliminator Pipe Threadlock

Aerobic Type Room Temperature Vulcanizing (RTV) Sealant

Aerobic type Room Temperature Vulcanizing (RTV) sealant cures when exposed to air. This type of sealant is used where 2 components (such as the intake manifold and the engine block) are assembled together.

Use the following information when using RTV sealant

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

Anaerobic Type Gasket Eliminator Sealant

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

Use the following information when using gasket eliminator sealant

1. Always follow all the safety recommendations and directions that are on the gasket eliminator sealant container.
2. Apply a continuous bead of gasket eliminator sealant to one flange. The surfaces to be sealed must be clean and dry.
3. Apply the gasket eliminator sealant evenly to get a uniform thickness of the gasket eliminator sealant on the sealing surface.
4. Tighten the fasteners in sequence (if specified) and to the proper torque specifications. DO NOT overtighten the fasteners.
5. After properly tightening the fasteners, remove the excess gasket eliminator sealant from the outside of the joint.

Anaerobic Type Threadlock Sealant

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

Use the following information when using threadlock sealant

1. Always follow all safety recommendations and directions that are on the threadlock sealant container.
2. The threaded surfaces to be sealed must be clean and dry.
3. Apply the threadlock sealant as specified on the threadlock sealant container.
4. Tighten the fasteners in sequence (if specified) and to the proper torque specifications. DO NOT overtighten the fasteners.

Anaerobic Type Pipe Sealant

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

Use the following information when using pipe sealant

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

Tools and Equipment

1. Special tools are listed and illustrated throughout this section with a complete listing at the end of the section. These tools or their equivalents, are specially designed to quickly and safely accomplish the operations for which they are intended. The use of these special tools will also minimize possible damage to engine components. Some precision measuring tools are required for inspection of certain critical components. Torque wrenches and a torque angle meter are necessary for the proper tightening of various fasteners.
2. To properly service the engine assembly, the following items should be readily available: Approved eye protection and safety gloves A clean, well-lit, work area A suitable parts cleaning tank A compressed air supply Trays or storage containers to keep parts and fasteners organized An adequate set of hand tools Approved engine repair stand An approved engine lifting device that will adequately support the weight of the components

Special Tools

Special Tools Illustration Tool Number/Description J 7872 Dial Indicator Set J 8037 Piston Ring Compressor J 8062 Valve Spring Compressor J 9666 Valve Spring Tester J 24270 Ridge Reamer J 25033-C Pulley Installer J 25034-C Pulley Remover J 26900-12 Dial Indicator J 26900-13 Magnetic Base J 26999 Compression Gage J 26999-20 Compression Gage Adapter J 28428-E High Intensity Black Light J 35667-9 Cylinder Head Leakdown Adapter J 36857 Engine Lift Bracket J 37228 Seal Cutter J 38820 Valve Stem Oil Seal Remover J 41712 Oil Pressure Switch Socket J 43181 Quick Connect Connector Remover J 43244 Relay Puller Pliers J 43654 Piston Pin Retainer Clip Remover/ Installer J 44640 Valve Stem Seal Installer J 44641 Crankshaft Rear Oil Seal Remover J 44642 Crankshaft Rear Oil Seal Installer J 44643 Flywheel Holding Tool J 44644 Crankshaft Front Oil Seal Remover J 44645 Crankshaft Front Oil Seal Installer J 44646 Valve Spring Compressor J 45059 Angle Meter J 45299 Engine Preluber J 46091 Charge Air Cooler Tester J 46594 Fuel Injector Puller

Scheme 131

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Scheme 144

Scheme 145

Scheme 146

See also:
• Cylinder Head Cleaning and Inspection
• Cylinder Head Replacement - Left
• Fuel Leaks
• Disassembled Views
• Base Engine Misfire without Internal Engine Noises
• Base Engine Misfire with Abnormal Internal Lower Engine Noises
• Base Engine Misfire with Abnormal Valve Train Noise
• Base Engine Misfire with Coolant Consumption
• Base Engine Misfire with Excessive Oil Consumption
• Engine Compression Test
• Engine Noise on Start-Up, but Only Lasting a Few Seconds
• Upper Engine Noise, Regardless of Engine Speed
• Lower Engine Noise, Regardless of Engine Speed
• Engine Noise Under Load
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Oil Pressure Diagnosis and Testing
• Oil Leak Diagnosis
• Drive Belt Tensioner Diagnosis
• Fuel in Engine Oil
• Special Tools
• Turbocharger Lack of Oil Supply
• Engine Mechanical Specifications
• Crankcase Ventilation System Inspection/Diagnosis
• Fastener Tightening Specifications