Engine Mechanical - 4.8l, 5.3l & 6.0l Chevrolet Avalanche I

Fastener Tightening Specifications

ENGINE MECHANICAL (4.8L, 5.3L AND 6.0L) FASTENER TIGHTENING SPECIFICATIONS

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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 , & 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/avalanche/i-2001-2006/remont/testing-diagnostics/#engine-controls-self-diagnostics-48l-53l-60l-flex-fuel-gasoline) in Engine Controls -4.8L, 5.3L, and 6.0L 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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) , «Engine Component Description»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) , «Lubrication Description»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) on page , «New Product Information»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__new-product-information) , and «Drive Belt System Description»(/chevrolet/avalanche/i-2001-2006/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. For a detailed explanation, refer to STRATEGY BASED DIAGNOSIS in General Information.

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Engine. Refer to CHECKING AFTERMARKET ACCESSORIES in Wiring Systems.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Check for the correct oil level, proper oil viscosity, and correct filter application.
4. Verify the exact operating conditions under which the concern exists. Note factors such as engine RPM, ambient temperature, engine temperature, amount of engine warm-up time, and other specifics.
5. Compare the engine sounds, if applicable, to a known good engine and make sure you are not trying to correct a normal condition.

Intermittent

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

Symptom List

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

1. «Base Engine Misfire Without Internal Engine Noises»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
2. «Base Engine Misfire With Abnormal Internal Lower Engine Noises»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
3. «Base Engine Misfire With Abnormal Valve Train Noise»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
4. «Base Engine Misfire With Coolant Consumption»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
5. «Base Engine Misfire With Excessive Oil Consumption»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
6. «ENGINE COMPRESSION TEST»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-compression-test)
7. «Engine Noise On Start-Up But Only Lasting A Few Seconds»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
8. «Upper Engine Noise, Regardless Of Engine Speed»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
9. «Lower Engine Noise, Regardless Of Engine Speed»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
10. «Engine Noise Under Load»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
11. «ENGINE WILL NOT CRANK - Crankshaft Will Not Rotate»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
12. «Coolant In Combustion Chamber»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
13. «Coolant In Engine Oil»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
14. «Oil Consumption Diagnosis»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
15. «OIL PRESSURE DIAGNOSIS AND TESTING»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__oil-pressure-diagnosis-and-testing)
16. «Oil Leak Diagnosis»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
17. «CYLINDER LEAKAGE TEST»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-leakage-test)
18. «DRIVE BELT CHIRPING DIAGNOSIS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
19. «DRIVE BELT SQUEAL DIAGNOSIS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
20. «DRIVE BELT WHINE DIAGNOSIS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
21. «DRIVE BELT RUMBLING DIAGNOSIS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
22. «DRIVE BELT VIBRATION DIAGNOSIS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
23. «DRIVE BELT FALLS OFF DIAGNOSIS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
24. «DRIVE BELT EXCESSIVE WEAR DIAGNOSIS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l)
25. «DRIVE BELT TENSIONER DIAGNOSIS»(/chevrolet/avalanche/i-2001-2006/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. Turn the ignition to the ON position.
6. Depress the accelerator pedal to position the throttle plate wide open.
7. Start with the compression gauge at zero and crank the engine through four compression strokes, four puffs.
8. Check the compression for each cylinder. Record the readings.
9. If a cylinder has low compression, inject approximately 15 ml (1 tablespoon) of engine oil into the combustion chamber through the spark plug hole. Recheck the compression and record the reading.
10. 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 1 035 kPa (150 psi), the lowest allowable pressure for any other cylinder would be 725 kPa (105 psi). (1 035 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. Then compression 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. «SPARK PLUGS»(/chevrolet/avalanche/i-2001-2006/remont/removal-installation/#engine-controls-removal-installation) in Engine Controls 4.8L, 5.3L, and 6.0L.
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.

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Oil Pressure Diagnosis and Testing

Tools Required

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

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1. With the vehicle on a level surface, run the vehicle for a few minutes. Allow adequate drain down time, 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, 10-15 seconds, and verify low or no oil pressure on the vehicle gage 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 J21867 or equivalent to the J42907 .
8. Run the engine and measure the engine oil pressure.
9. Compare the readings to «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LR4 VIN V)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LM7 VIN T)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (L59 VIN Z)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ4 VIN U)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ9 VIN N)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
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/avalanche/i-2001-2006/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/avalanche/i-2001-2006/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/avalanche/i-2001-2006/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.

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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 peeling. Peeling 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 peeling will only be a temporary repair.

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.

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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.

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.

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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.

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.

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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 peeling is a normal condition and acceptable. When the peeling is severe the drive belt(s) does not have a smooth surface for proper operation.

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.

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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.

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.

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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).

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.

Scheme 99

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 100

Note. Allowing the drive belt tensioner to snap into the free position may result in damage to the tensioner.

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.

1. Remove the drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «DRIVE BELT REPLACEMENT - AIR CONDITIONING»(/chevrolet/avalanche/i-2001-2006/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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «DRIVE BELT TENSIONER REPLACEMENT - AIR CONDITIONING»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
4. Install the drive belt. Refer to of «DRIVE BELT REPLACEMENT - ACCESSORY»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «DRIVE BELT REPLACEMENT - AIR CONDITIONING»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

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1. Loosen the air cleaner outlet duct clamps at the following locations: The throttle body The mass airflow/intake air temperature (MAF/IAT) sensor
2. Disconnect the radiator inlet hose clip from the outlet duct.
3. Remove the air cleaner outlet duct.
4. Install a breaker bar with hex-head socket to the drive belt tensioner bolt.
5. Rotate the drive belt tensioner clockwise in order to relieve tension on the belt (1).
6. Remove the belt (1) from the pulleys and the drive belt tensioner.
7. Slowly release the tension on the drive belt tensioner.
8. Remove the breaker bar and socket and from the drive belt tensioner bolt.
9. Clean and inspect the belt surfaces of all the pulleys.

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1. Route the drive belt (1) 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 (1) 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 (1) for proper installation and alignment.
8. Align the arrow (2) at the throttle body end of the duct with the throttle body attaching stud (1).
9. Install the air cleaner outlet duct.
10. Connect the radiator inlet hose clip to the outlet duct. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
11. Tighten the air cleaner outlet duct clamp screws at the following locations: The throttle body The MAF/IAT sensor Tighten Tighten the screws to 7 N.m (62 lb in).

Scheme 106

Scheme 107

1. Remove the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Raise and suitably support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/chevrolet/avalanche/i-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the engine shield bolts.
4. Remove the engine shield.
5. Install a ratchet into the air conditioning (A/C) belt tensioner adapter opening.
6. Rotate the A/C belt tensioner clockwise in order to relieve tension on the belt.
7. Remove the A/C belt from the pulleys.
8. Slowly release the tension on the A/C belt tensioner.
9. Remove the ratchet from the A/C belt tensioner.
10. Clean and inspect the belt surfaces of all the pulleys.

Scheme 108

Scheme 109

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 engine shield. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
10. Install the engine shield bolts. Tighten Tighten the bolts to 20 N.m (15 lb ft).
11. Lower the vehicle.
12. Install the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 110

1. Loosen the drive belt idler pulley bolt.
2. Remove the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
3. Remove the drive belt idler pulley and bolt.

Scheme 111

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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) . NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
3. Tighten the drive belt idler pulley bolt. Tighten Tighten the bolt to 50 N.m (37 lb ft).

Scheme 112

1. Remove the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the drive belt tensioner bolts.
3. Remove the drive belt tensioner.

Scheme 113

1. Install the drive belt tensioner.
2. Install the drive belt tensioner bolts. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
3. Tighten the drive belt tensioner bolts. Tighten Tighten the bolts to 50 N.m (37 lb ft).
4. Install the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 114

1. Remove the air conditioning (A/C) drive belt. Refer to «DRIVE BELT REPLACEMENT - AIR CONDITIONING»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the A/C belt tensioner bolts.
3. Remove the A/C belt tensioner.

Scheme 115

1. Install the A/C belt tensioner. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the A/C belt tensioner bolts. Tighten Tighten the bolts to 50 N.m (37 lb ft)
3. Install the A/C drive belt. Refer to «DRIVE BELT REPLACEMENT - AIR CONDITIONING»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Engine Mount Inspection

Note. Broken or deteriorated mounts can cause misalignment and destruction of certain drive train components. When a single mount breaks, the remaining mounts are subjected to abnormally high stresses.

Note. 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. Due to the small clearance between the oil pan and the oil pump screen, jacking against the oil pan may cause the pan to be bent against the pump screen. This will result in a damaged oil pickup unit.

1. Measure the engine movement at the engine mount in order to check for damage to the rubber portions of the mount. 1.1. Apply the park brake. 1.2. Start the engine. 1.3. Firmly apply and hold the primary brakes. 1.4. Have an assistant stand to the side of the vehicle in order to observe for engine movement. 1.5. Slightly load the engine shifting from drive to reverse a few times. 1.6. If the engine moves more than 24 mm (0.945 in) from the at rest position, in either direction, check for loose engine mount bolts.
2. If the engine mount bolt torque is within specifications, check the condition of the engine mount.
3. Replace the engine mount if any of the following conditions exist: Heat check cracks cover the rubber cushion surface. The rubber cushion is separated from the metal plate of the mount. There is a split through the rubber cushion.

Removal Procedure

Note. 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. Due to the small clearance between the oil pan and the oil pump screen, jacking against the oil pan may cause the pan to be bent against the pump screen. This will result in a damaged oil pickup unit.

Scheme 116

Scheme 117

Scheme 118

Scheme 119

1. Remove the engine mount-to-engine mount bracket bolts. (Right side shown, left side similar).
2. If vehicle is a 2 wheel drive (2WD), raise the vehicle to a height to work through the front wheelhouse opening.
3. If vehicle is a 4 wheel drive (4WD), raise the vehicle in order to remove the front tires and wheels.
4. Remove the left front tire and wheel. Refer to TIRE AND WHEEL REMOVAL AND INSTALLATION in Tires and Wheels.
5. Remove the wheelhouse inner panel push pin retainers (2).
6. Remove the wheelhouse inner panel (1).
7. Remove the engine shield bolts.
8. Remove the engine shield. Important: DO NOT raise and/or support the engine by the crankshaft balancer, or oil pan.
9. Raise and suitably support the engine using adjustable (screw type) jack stands.
10. Remove the engine mount bolts.
11. For vehicles with 4WD, remove the front propeller shaft. Refer to «PROPELLER SHAFT REPLACEMENT -- FRONT»(/chevrolet/avalanche/i-2001-2006/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) in Propeller Shaft.
12. Remove the left engine mount.

Scheme 120

Scheme 121

Scheme 122

Scheme 123

1. Position the left engine mount to the engine. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the engine mount bolts. Tighten Tighten the engine mount bolts to 50 N.m (37 lb ft).
3. Lower the engine.
4. Remove the adjustable jack stands.
5. Install the front propeller shaft. Refer to «PROPELLER SHAFT REPLACEMENT -- FRONT»(/chevrolet/avalanche/i-2001-2006/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) in Propeller Shaft.
6. Position the engine shield to the vehicle.
7. Install the engine shield bolts. Tighten Tighten the engine shield bolts to 20 N.m (15 lb ft).
8. Lower the vehicle.
9. Install the left front tire and wheel. Refer to «TIRE AND WHEEL REMOVAL AND INSTALLATION»(/chevrolet/avalanche/i-2001-2006/remont/wheel-tire-system/#tires-wheels__tire-and-wheel-removal-and-installation) in Tires and Wheels.
10. Install the wheelhouse inner panel push pin retainers (2).
11. Install the wheelhouse inner panel (1).
12. Install the engine mount-to-engine mount bracket bolts. (Right side shown, left side similar). Tighten Tighten the engine mount-to-engine mount bracket bolts to 65 N.m (48 lb ft).

Scheme 124

1. Remove the engine mount. Refer to «ENGINE MOUNT REPLACEMENT - LEFT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the engine mount bracket bolts.
3. Remove the engine mount bracket.

Scheme 125

1. Install the engine mount bracket. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the engine mount bracket bolts. Tighten Tighten the engine mount bracket bolts to 75 N.m (55 lb ft).
3. Install the engine mount. Refer to «ENGINE MOUNT REPLACEMENT - LEFT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 126

Scheme 127

Scheme 128

1. Remove the engine mount-to-engine mount bracket bolts.
2. Raise and suitably support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/chevrolet/avalanche/i-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the engine shield bolts.
4. Remove the engine shield.
5. Remove the air conditioning (A/C) compressor. Refer to COMPRESSOR REPLACEMENT (LR4, LM7, AND LQ4) in Heating, Ventilation, and Air Conditioning.
6. Remove the starter motor. Refer to STARTER MOTOR REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES) in Engine Electrical. Important: DO NOT raise and/or support the engine by the crankshaft balancer, or oil pan.
7. Raise and suitably support the engine using adjustable (screw type) jack stands.
8. Remove the engine mount bolts.
9. Remove the right engine mount.

Scheme 129

Scheme 130

Scheme 131

1. Position the right engine mount to the engine. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the engine mount bolts. Tighten Tighten the engine mount bolts to 50 N.m (37 lb ft).
3. Lower the engine.
4. Remove the adjustable jack stands.
5. Install the starter motor. Refer to STARTER MOTOR REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES) in Engine Electrical.
6. Install the A/C compressor. Refer to COMPRESSOR REPLACEMENT (LR4, LM7, AND LQ4) in Heating, Ventilation, and Air Conditioning.
7. Position the engine shield to the vehicle.
8. Install the engine shield bolts. Tighten Tighten the engine shield bolts to 20 N.m (15 lb ft).
9. Lower the vehicle.
10. Install the engine mount-to-engine mount bracket bolts. Tighten Tighten the engine mount-to-engine mount bracket bolts to 65 N.m (48 lb ft).

Scheme 132

1. Remove the engine mount. Refer to «ENGINE MOUNT REPLACEMENT - RIGHT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the engine mount bracket bolts.
3. Remove the engine mount bracket.

Scheme 133

1. Install the engine mount bracket. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
2. Install the engine mount bracket bolts. Tighten Tighten the engine mount bracket bolts to 75 N.m (55 lb ft).
3. Install the engine mount. Refer to «ENGINE MOUNT REPLACEMENT - RIGHT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 134

Scheme 135

1. Loosen the intake manifold sight shield bolt.
2. Remove the sight shield from the sight shield retainer.
3. Remove the sight shield retainer bolts and the retainer, if required.

Installation Procedure

Note. Refer to FASTENER NOTICE in Cautions and Notices.

Scheme 136

Scheme 137

1. Install the sight shield retainer and the bolts, if required. Tighten Tighten the bolts to 5 N.m (44 lb in). NOTE: Use care when installing the engine sight shield to avoid contacting the manifold absolute pressure (MAP) sensor wire harness connector. Loss of engine performance or engine damage may result.
2. Install the intake manifold sight shield to the retainer. Tighten Tighten the bolt to 10 N.m (89 lb in).

Scheme 138

Scheme 139

1. Loosen the intake manifold sight shield bolt.
2. Remove the sight shield from the sight shield retainer.
3. Loosen the left fuel rail cover bolts.
4. Remove the left fuel rail cover.
5. Remove the surge tank/heater hoses from the clip on the right fuel rail cover.
6. Loosen the right fuel rail cover bolts.
7. Remove the right fuel rail cover.
8. Remove the sight shield retainer bolts and retainer, if required.

Note. Refer to FASTENER NOTICE in Cautions and Notices.

Scheme 140

Scheme 141

1. Install the sight shield retainer and bolts, if required. Tighten Tighten the bolts to 5 N.m (44 lb in).
2. Install the right fuel rail cover.
3. Tighten the right fuel rail cover bolts. Tighten Tighten the bolts to 9 N.m (80 lb in).
4. Install the surge tank/heater hoses to the clip on the right fuel rail cover.
5. Install the left fuel rail cover.
6. Tighten the left fuel rail cover bolts. Tighten Tighten the bolts to 9 N.m (80 lb in). NOTE: Use care when installing the engine sight shield to avoid contacting the manifold absolute pressure (MAP) sensor wire harness connector. Loss of engine performance or engine damage may result.
7. Install the sight shield to the sight shield retainer.
8. Tighten the intake manifold sight shield bolt. Tighten Tighten the bolt to 9 N.m (80 lb in).

Scheme 142

1. Remove the engine sight shield, if required. Refer to «ENGINE SIGHT SHIELD REPLACEMENT (4.8L, 5.3L, AND 6.0L (RPO LQ4))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «ENGINE SIGHT SHIELD REPLACEMENT (6.0L (RPO LQ9))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
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 143

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 sight shield, if required. Refer to «ENGINE SIGHT SHIELD REPLACEMENT (4.8L, 5.3L, AND 6.0L (RPO LQ4))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «ENGINE SIGHT SHIELD REPLACEMENT (6.0L (RPO LQ9))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 144

Scheme 145

1. Remove the engine sight shield. Refer to «ENGINE SIGHT SHIELD REPLACEMENT (4.8L, 5.3L, AND 6.0L (RPO LQ4))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «ENGINE SIGHT SHIELD REPLACEMENT (6.0L (RPO LQ9))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
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 146

Scheme 147

1. Install the hose/tube as necessary.
2. Install the vent hose to the throttle body and the valve rocker arm cover.
3. Install the PCV valve (2) to the tube (1).
4. Install the PCV tube (1) to the intake manifold and valve rocker arm cover.
5. Install the engine sight shield. Refer to «ENGINE SIGHT SHIELD REPLACEMENT (4.8L, 5.3L, AND 6.0L (RPO LQ4))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «ENGINE SIGHT SHIELD REPLACEMENT (6.0L (RPO LQ9))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

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

Scheme 148

Scheme 149

Scheme 150

Scheme 151

Scheme 152

Scheme 153

Scheme 154

Scheme 155

1. Remove the throttle body. Refer to «THROTTLE BODY»(/chevrolet/avalanche/i-2001-2006/remont/removal-installation/#engine-controls-removal-installation__throttle-body) in Engine Controls - 4.8L, 5.3L, and 6.0L.
2. Remove the fuel injectors. Refer to «FUEL RAIL ASSEMBLY»(/chevrolet/avalanche/i-2001-2006/remont/removal-installation/#engine-controls-removal-installation) in Engine Controls - 4.8L, 5.3L, and 6.0L.
3. Disconnect the following electrical connectors: The manifold absolute pressure (MAP) sensor (1) The knock sensor (2)
4. Remove the knock sensor harness electrical connector from the intake manifold.
5. Set the electrical harness aside.
6. If equipped with vacuum assisted brakes, remove the vacuum brake booster hose from the rear of the intake manifold.
7. Remove the positive crankcase ventilation (PCV) hose with valve.
8. Remove the MAP sensor (1) from the intake manifold.
9. Remove the evaporative emission (EVAP) purge solenoid vent tube by performing the following: 9.1. Remove the EVAP tube end from the solenoid (1). 9.2. Remove the EVAP tube end from the vapor pipe (2).
10. Remove the EVAP purge solenoid bolt (2), solenoid (3), and isolator (1) from the intake manifold.
11. Loosen the intake manifold bolts.
12. Remove the intake manifold.
13. Remove the intake manifold gaskets (1) from the intake manifold.
14. Discard the old intake manifold gaskets.
15. If required, clean and inspect the intake manifold. Refer to «Intake Manifold Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 156

Scheme 157

Scheme 158

Scheme 159

Scheme 160

Scheme 161

Scheme 162

Scheme 163

Scheme 164

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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
4. Tighten the intake manifold bolts. Tighten 4.1. Tighten the bolts a first pass in sequence to 5 N.m (44 lb in). 4.2. Tighten the 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 bolt to 10 N.m (89 lb in).
6. Install the EVAP purge solenoid vent tube to the solenoid (1) and vapor pipe (2). Important: Lightly coat the MAP sensor seal with clean engine oil before installing.
7. Install the MAP sensor (1) to the intake manifold.
8. Install the PCV hose with valve.
9. If equipped with vacuum assisted brakes, install the vacuum brake booster hose to the rear of the intake manifold.
10. Route the electrical harness into position over the engine.
11. Connect the knock sensor harness electrical connector to the intake manifold.
12. Connect the following electrical connectors. The MAP sensor (1) The knock sensor (2)
13. Install the fuel injectors. Refer to «FUEL RAIL ASSEMBLY»(/chevrolet/avalanche/i-2001-2006/remont/removal-installation/#engine-controls-removal-installation) in Engine Controls - 4.8L, 5.3L, and 6.0L.
14. Install the throttle body. Refer to «THROTTLE BODY»(/chevrolet/avalanche/i-2001-2006/remont/removal-installation/#engine-controls-removal-installation__throttle-body) in Engine Controls - 4.8L, 5.3L, and 6.0L.

Scheme 165

Scheme 166

Scheme 167

Scheme 168

1. Remove the intake manifold. Refer to «INTAKE MANIFOLD REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/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. If required, clean and inspect the engine valley cover. Refer to «Engine Valley Cover Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-valley-cover-cleaning-and-inspection) .

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

Scheme 169

Scheme 170

Scheme 171

Scheme 172

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 with a NEW gasket onto the engine block. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 173

Scheme 174

Scheme 175

Scheme 176

Scheme 177

1. Remove the engine sight shield, if required. Refer to «ENGINE SIGHT SHIELD REPLACEMENT (4.8L, 5.3L, AND 6.0L (RPO LQ4))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «ENGINE SIGHT SHIELD REPLACEMENT (6.0L (RPO LQ9))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the connector position assurance (CPA) lock.
3. Disconnect the main electrical connector (2) feeding the ignition coils.
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.
8. Remove the ignition bracket.
9. Remove the positive crankcase ventilation (PCV) hose.
10. Loosen the valve rocker arm cover bolts.
11. Remove the valve rocker arm cover.
12. Remove and discard the old gasket (1).
13. If required, clean and inspect the rocker arm cover. Refer to «Valve Rocker Arm Cover Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__valve-rocker-arm-cover-cleaning-and) .

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. If the PCV valve grommet has been removed from the rocker cover, install a NEW grommet during assembly.

Scheme 178

Scheme 179

Scheme 180

Scheme 181

Scheme 182

1. Install a NEW rocker cover gasket (1).
2. Install the valve rocker arm cover. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
3. Tighten the rocker arm cover bolts. Tighten Tighten the bolts to 12 N.m (106 lb in).
4. Install the PCV hose to the rocker arm cover.
5. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the coil bracket studs.
6. Install the ignition coil bracket.
7. Install the ignition coil bracket studs. Tighten Tighten the studs to 12 N.m (106 lb in).
8. Install the spark plug wires to the ignition coils.
9. Position the engine harness, if necessary.
10. Install the harness clips (1).
11. Connect the main electrical connector (2) feeding the ignition coils.
12. Install the CPA lock.
13. Install the engine sight shield, if required. Refer to «ENGINE SIGHT SHIELD REPLACEMENT (4.8L, 5.3L, AND 6.0L (RPO LQ4))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «ENGINE SIGHT SHIELD REPLACEMENT (6.0L (RPO LQ9))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 183

Scheme 184

Scheme 185

Scheme 186

Scheme 187

Scheme 188

Scheme 189

1. Remove the engine sight shield, if required. Refer to «ENGINE SIGHT SHIELD REPLACEMENT (4.8L, 5.3L, AND 6.0L (RPO LQ4))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «ENGINE SIGHT SHIELD REPLACEMENT (6.0L (RPO LQ9))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the connector position assurance (CPA) lock.
3. Disconnect the main electrical connector (1) feeding the ignition coils.
4. Remove the harness clips (2).
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. If equipped with the 4.8L, 5.3L, or 6.0L (LQ4) engine, perform the following: 7.1. Reposition the surge tank/heater hoses from the heater hose bracket. 7.2. Remove the heater hose bracket nut and bracket.
8. Remove the ignition coil bracket studs.
9. Remove the ignition coil bracket.
10. Remove the positive crankcase ventilation (PCV) hose.
11. Loosen the valve rocker arm cover bolts.
12. Remove the valve rocker arm cover.
13. Remove and discard the old gasket (1).
14. Remove the oil fill tube from the rocker cover, if required.
15. If required, clean and inspect the rocker arm cover. Refer to «Valve Rocker Arm Cover Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__valve-rocker-arm-cover-cleaning-and) .

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.

Scheme 190

Scheme 191

Scheme 192

Scheme 193

Scheme 194

Scheme 195

Scheme 196

1. Lubricate the O-ring seal of the NEW oil fill tube with clean engine oil.
2. Insert the NEW oil fill tube into the rocker arm cover. Rotate the tube clockwise until locked in the proper position.
3. Install the oil fill cap into the tube. Rotate the cap clockwise until locked in the proper position.
4. Install a NEW rocker cover gasket (1) into the valve rocker cover lip.
5. Install the valve rocker arm cover. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
6. Tighten the rocker arm cover bolts. Tighten Tighten the bolts to 12 N.m (106 lb in).
7. Install the PCV hose.
8. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the coil bracket studs.
9. Install the ignition coil bracket.
10. Install the ignition coil bracket studs. Tighten Tighten the studs to 12 N.m (106 lb in).
11. If equipped with the 4.8L, 5.3L, or 6.0L (LQ4) engine, perform the following: 11.1. Install the heater hose bracket and nut. Tighten Tighten the nut to 9 N.m (80 lb in). 11.2. Position the surge tank/heater hoses to the heater hose bracket.
12. Install the spark plug wires to the ignition coils.
13. Position the engine harness, if necessary.
14. Install the harness clips (2).
15. Connect the main electrical connector (1) feeding the ignition coils.
16. Install the CPA lock.
17. Install the engine sight shield, if required. Refer to «ENGINE SIGHT SHIELD REPLACEMENT (4.8L, 5.3L, AND 6.0L (RPO LQ4))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «ENGINE SIGHT SHIELD REPLACEMENT (6.0L (RPO LQ9))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 197

Scheme 198

Scheme 199

1. Remove the rocker arm cover. Refer to «VALVE ROCKER ARM COVER REPLACEMENT - LEFT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «VALVE ROCKER ARM COVER REPLACEMENT - RIGHT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) . Important: Place the rocker arms, push rods, and pivot support, in a rack so that they can be installed in the same location from which they were removed.
2. Remove the rocker arm bolts.
3. Remove the rocker arms.
4. Remove the rocker arm pivot support.
5. Remove the push rods.
6. If required, clean and inspect the rocker arms and pushrod. Refer to «Valve Rocker Arm and Push Rods Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/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 200

Scheme 201

Scheme 202

Scheme 203

1. Lubricate the rocker arms and pushrod with clean engine oil.
2. Lubricate the flange of the rocker arm bolts with clean engine oil. Lubricate the flange or washer surface of the bolt that will contact the rocker arm.
3. Install the rocker arm pivot support. Important: Make sure that the pushrod seat properly to the valve lifter sockets.
4. Install the pushrod. Important: Make sure that the pushrod 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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
7. With the engine in the number one firing position, tighten the following rocker arm bolts: Tighten Tighten cylinders 1,2,7 and 8 exhaust valve rocker arm bolts to 30 N.m (22 lb ft). Tighten 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 rocker arm bolts: Tighten Tighten cylinders 3, 4, 5 and 6 exhaust valve rocker arm bolts to 30 N.m (22 lb ft). Tighten cylinders 2, 6, 7 and 8 intake valve rocker arm bolts to 30 N.m (22 lb ft).
10. Install the rocker arm cover. Refer to «VALVE ROCKER ARM COVER REPLACEMENT - LEFT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «VALVE ROCKER ARM COVER REPLACEMENT - RIGHT»(/chevrolet/avalanche/i-2001-2006/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

Scheme 204

Scheme 205

Scheme 206

Scheme 207

Scheme 208

1. Remove the rocker arm. Refer to «VALVE ROCKER ARM AND PUSH ROD REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/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 the J 22794 into the spark plug hole.
7. Attach an air hose to the J 22794 .
8. Apply compressed air to the J 22794 in order to hold the valves in place.
9. Use the 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 209

Scheme 210

Scheme 211

Scheme 212

Scheme 213

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 the J 22794 from the spark plug port. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
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 rocker arm. Refer to «VALVE ROCKER ARM AND PUSH ROD REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Scheme 214

Scheme 215

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

Scheme 216

Scheme 217

1. Lubricate the O-ring seal with clean engine oil.
2. Install a NEW O-ring seal onto the oil level indicator tube, if required.
3. Install the oil level indicator tube between the exhaust manifold and engine block.
4. Raise and suitably support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/chevrolet/avalanche/i-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
5. Install the oil level indicator tube into the block. The tube must be installed with the collar flush to the block.
6. Lower the vehicle. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
7. Install the oil level indicator tube bolt Tighten Tighten the bolt to 25 N.m (18 lb ft).
8. Install the oil level indicator.

Cylinder Head Replacement - Left

Tools Required

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

Scheme 218

Scheme 219

Scheme 220

1. Remove the generator bracket. Refer to «GENERATOR (4.8L, 5.3L & 6.0L ENGINES)»(/chevrolet/avalanche/i-2001-2006/remont/charging-system/#charging-system) in Engine Electrical.
2. Remove the intake manifold. Refer to «Intake Manifold Removal»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__intake-manifold-removal) .
3. Remove the coolant air bleed pipe. Refer to «COOLANT AIR BLEED PIPE ASSEMBLY REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/avalanche/i-2001-2006/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
4. Remove the left exhaust manifold. Refer to «EXHAUST MANIFOLD REPLACEMENT -- LEFT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/avalanche/i-2001-2006/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
5. Remove the pushrod. Refer to «VALVE ROCKER ARM AND PUSH ROD REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) . Important: The cylinder head bolts are NOT reusable.
6. Remove and discard the cylinder head bolts (1, 2, 3). NOTE: After removal, place the cylinder head on two wood blocks to prevent damage to sealing surfaces.
7. Remove the cylinder head.
8. Remove and discard the cylinder head gasket.
9. If required, clean and inspect the cylinder head. Refer to «Cylinder Head Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-cleaning-and-inspection) .

Note. Clean all dirt, debris, and coolant from the engine block cylinder head bolt holes. Failure to remove all foreign material may result in damaged threads, improperly tightened fasteners or damage to components.

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 221

Scheme 222

Scheme 223

Scheme 224

Scheme 225

Scheme 226

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 thread locking material.
2. Use spray cleaner GM P/N 12346139, P/N 12377981, (Canadian 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, location (a) 8.3 mm (0.327 in).
5. When properly installed, with FRONT on the left side, the tab on the cylinder head gasket should be located left of center or closer to the front of the engine.
6. Install the NEW cylinder head gasket.
7. Install the cylinder head.
8. Install NEW cylinder head bolts (1, 2, 3). NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
9. Tighten the cylinder head bolts. Tighten 9.1. Tighten the M11 bolts a first pass in sequence to 30 N.m (22 lb ft). 9.2. Tighten the M11 bolts a second pass in sequence to 90 degrees using J 36660-A . 9.3. Tighten the M11 bolts (1, 2, 3, 4, 5, 6, 7, 8) to 90 degrees and the M11 bolts (9 and 10) to 50 degrees a final pass in sequence using J 36660-A . 9.4. Tighten the M8 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.
10. Install the pushrod. Refer to «VALVE ROCKER ARM AND PUSH ROD REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
11. Install the left exhaust manifold. Refer to «EXHAUST MANIFOLD REPLACEMENT -- LEFT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/avalanche/i-2001-2006/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
12. Install the coolant air bleed pipe. Refer to «COOLANT AIR BLEED PIPE ASSEMBLY REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/avalanche/i-2001-2006/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
13. Install the intake manifold. Refer to «Intake Manifold Installation»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__intake-manifold-installation) .
14. Install the generator bracket. Refer to «GENERATOR (4.8L, 5.3L & 6.0L ENGINES)»(/chevrolet/avalanche/i-2001-2006/remont/charging-system/#charging-system) in Engine Electrical.

Cylinder Head Replacement - Right

Tools Required

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

Scheme 227

Scheme 228

Scheme 229

1. Remove the oil level indicator. Refer to «OIL LEVEL INDICATOR AND TUBE REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the intake manifold. Refer to «Intake Manifold Removal»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__intake-manifold-removal) .
3. Remove the coolant air bleed pipe. Refer to «COOLANT AIR BLEED PIPE ASSEMBLY REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/avalanche/i-2001-2006/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
4. Remove the right exhaust manifold. Refer to «EXHAUST MANIFOLD REPLACEMENT -- RIGHT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/avalanche/i-2001-2006/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
5. Remove the pushrod. Refer to «VALVE ROCKER ARM AND PUSH ROD REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) . Important: The cylinder head bolts are NOT reusable.
6. Remove and discard the cylinder head bolts (1, 2, 3). NOTE: After removal, place the cylinder head on two wood blocks to prevent damage to sealing surfaces.
7. Remove the cylinder head.
8. Remove and discard the cylinder head gasket.
9. If required, clean and inspect the cylinder head. Refer to «Cylinder Head Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-cleaning-and-inspection) .

Note. Clean all dirt, debris, and coolant from the engine block cylinder head bolt holes. Failure to remove all foreign material may result in damaged threads, improperly tightened fasteners or damage to components.

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 230

Scheme 231

Scheme 232

Scheme 233

Scheme 234

Scheme 235

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 P/N 12346139, P/N 12377981, (Canadian 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, location (a) 8.3 mm (0.327 in).
5. When properly installed, with FRONT on the right side, the tab on the cylinder head gasket should be located right of center or closer to the front of the engine.
6. Install the NEW cylinder head gasket.
7. Install the cylinder head.
8. Install the NEW cylinder head bolts. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
9. Tighten the cylinder head bolts. Tighten 9.1. Tighten the M11 bolts a first pass in sequence to 30 N.m (22 lb ft). 9.2. Tighten the M11 bolts a second pass in sequence to 90 degrees using J 36660-A . 9.3. Tighten the M11 bolts (1, 2, 3, 4, 5, 6, 7, 8) to 90 degrees and the M11 bolts (9 and 10) to 50 degrees a final pass in sequence using J 36660-A . 9.4. Tighten the M8 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.
10. Install the pushrod. Refer to «VALVE ROCKER ARM AND PUSH ROD REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
11. Install the right exhaust manifold. Refer to «EXHAUST MANIFOLD REPLACEMENT -- RIGHT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/avalanche/i-2001-2006/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
12. Install the coolant air bleed pipe. Refer to «COOLANT AIR BLEED PIPE ASSEMBLY REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES)»(/chevrolet/avalanche/i-2001-2006/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
13. Install the intake manifold. Refer to «Intake Manifold Installation»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__intake-manifold-installation) .
14. Install the oil level indicator. Refer to «OIL LEVEL INDICATOR AND TUBE REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Valve Lifter Replacement

Tools Required

J 3049-A Valve Lifter Remover

Scheme 236

Scheme 237

Scheme 238

Scheme 239

1. Remove the cylinder head and gasket. Refer to «CYLINDER HEAD REPLACEMENT - LEFT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-replacement-left) or «CYLINDER HEAD REPLACEMENT - RIGHT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-replacement-right) .
2. Remove the valve lifter guide bolts.
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. If required, clean and inspect the valve lifters. Refer to «Valve Lifters and Guides Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/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 240

Scheme 241

Scheme 242

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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
4. Install the valve lifter guide bolts. Tighten Tighten the bolt to 12 N.m (106 lb in).
5. Install the cylinder head and gasket. Refer to «CYLINDER HEAD REPLACEMENT - LEFT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-replacement-left) or «CYLINDER HEAD REPLACEMENT - RIGHT»(/chevrolet/avalanche/i-2001-2006/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 243

Scheme 244

Scheme 245

1. Remove the air conditioning (A/C) drive belt, if equipped. Refer to «DRIVE BELT REPLACEMENT - AIR CONDITIONING»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the accessory drive belt, if not equipped with A/C. Refer to «DRIVE BELT TENSIONER REPLACEMENT - AIR CONDITIONING»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
3. Remove the fan shroud - lower. Refer to FAN SHROUD REPLACEMENT - LOWER in Engine Cooling.
4. Remove the starter motor. Refer to STARTER MOTOR REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES) in Engine Electrical. 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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
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. Install 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. If required, clean and inspect the crankshaft balancer. Refer to «Crankshaft Balancer Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/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 246

Scheme 247

Scheme 248

1. Install the crankshaft balancer onto the end of the crankshaft.
2. Use the J 41665 in order to install the crankshaft balancer. 2.1. Assemble the threaded rod, nut, washer and installer. Insert the smaller end of the installer into the front of the balancer. 2.2. Use a wrench and hold the hex end of the threaded rod. 2.3. Use a second wrench and rotate the installation tool nut clockwise until the balancer is started onto the crankshaft. 2.4. Remove the tool and reverse the installation tool. Position the larger end of the installer against the front of the balancer. 2.5. Use a wrench and hold the hex end of the threaded rod. 2.6. Use a second wrench and rotate the installation tool nut clockwise until the balancer is installed onto the crankshaft. 2.7. Remove the balancer installation tool.
3. Install the used crankshaft balancer bolt. Tighten Tighten the USED 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 6.1. Tighten the bolt a first pass to 50 N.m (37 lb ft). 6.2. Tighten the 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, AND 6.0L ENGINES) in Engine Electrical.
9. Install the fan shroud - lower. Refer to FAN SHROUD REPLACEMENT - LOWER in Engine Cooling.
10. Install the accessory drive belt (if not equipped with A/C). Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
11. Install the A/C drive belt (if equipped). Refer to «DRIVE BELT REPLACEMENT - AIR CONDITIONING»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
12. Perform the crankshaft position (CKP) system variation learn procedure. «CKP SYSTEM VARIATION LEARN PROCEDURE»(/chevrolet/avalanche/i-2001-2006/remont/removal-installation/#engine-controls-removal-installation__ckp-system-variation-learn-procedure) in Engine Controls - 4.8L, 5.3L, and 6.0L.

Crankshaft Front Oil Seal Replacement

Tools Required

J 41478 Crankshaft Front Oil Seal Installer

Scheme 249

1. Remove the crankshaft balancer. Refer to «CRANKSHAFT BALANCER REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/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.

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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. 5.1. Use a wrench and hold the hex on the installer bolt. 5.2. Use a second wrench and rotate the installer nut clockwise until the seal bottoms in the cover bore. 5.3. 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/avalanche/i-2001-2006/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

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1. Remove the water pump. Refer to WATER PUMP REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES) in Engine Cooling.
2. Remove the crankshaft balancer. Refer to «CRANKSHAFT BALANCER REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__crankshaft-balancer-replacement) .
3. Remove the oil pan-to-front cover bolts (1).
4. Remove the front cover bolts.
5. Remove the front cover and gasket.
6. Discard the front cover gasket.
7. If required, clean and inspect the engine front cover. Refer to «Engine Front Cover Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/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.

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1. Apply a 5 mm (0.20 in) bead of sealant GM 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 (1) 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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
7. Install the crankshaft balancer bolt until snug. Do not overtighten. Tighten 7.1. Tighten the oil pan to front cover bolts to 25 N.m (18 lb ft). 7.2. 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/avalanche/i-2001-2006/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) in Engine Cooling.

Crankshaft Rear Oil Seal Replacement

Tools Required

J 41479 Crankshaft Rear Oil Seal Installer

Scheme 257

1. Remove the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/avalanche/i-2001-2006/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.

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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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Engine Rear Cover Replacement

Tools Required

J 41476 Front and Rear Cover Alignment-at crankshaft seal area

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1. Remove the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/avalanche/i-2001-2006/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. If required, clean and inspect the rear cover. Refer to «Engine Rear Cover Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-rear-cover-cleaning-and-inspection) .

Important

Scheme 262

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.

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1. Apply a 5 mm (0.20 in) bead of sealant GM 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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
7. Tighten the J 41476 mounting bolts until snug. Do not overtighten. Tighten 7.1. Tighten the oil pan-to-rear cover bolts to 12 N.m (106 lb in). 7.2. 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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__crankshaft-rear-oil-seal-replacement) .
10. Install the engine flywheel. Refer to «Engine Flywheel Replacement»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

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

Note. Refer to FASTENER NOTICE in Cautions and Notices.

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

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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).

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1. Install the oil filter bypass valve (2). NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
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 274

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

Note. Refer to FASTENER NOTICE in Cautions and Notices.

Scheme 275

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

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1. If equipped with four-wheel drive (4WD), 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 4WD, remove the differential carrier lower mounting bolt and nut.
4. If equipped with 4WD, remove the differential carrier upper mounting bolt and nut.
5. Lower the front drive axle.
6. Remove the transmission cover bolt.
7. If equipped, remove the oil pan skid plate bolts.
8. Remove the oil pan skid plate.
9. Remove the crossbar bolts.
10. Remove the crossbar.
11. Remove the transmission cover bolt and cover.
12. Drain the engine oil and remove the engine oil filter.
13. Re-install the drain plug and oil filter until snug.
14. If equipped with the 4L60-E automatic transmission, remove the transmission bolt and stud on the right side.
15. Remove the bottom bolt on the left side.
16. If equipped with the 4L80-E automatic transmission, remove the transmission converter cover bolts.
17. Disconnect the oil level sensor electrical connector (6).
18. Remove the battery cable channel bolt.
19. Slide the channel pin out of the oil pan tab.
20. Remove the positive battery cable clip bolt.
21. Remove the oil pan bolts.
22. 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.
23. Drill (3) out the oil pan gasket retaining rivets (2), if required.
24. Remove the gasket (1) from the pan.
25. Discard the gasket and rivets.
26. If require, clean and inspect the engine oil pan. Refer to «Oil Pan Cleaning and Inspection»(/chevrolet/avalanche/i-2001-2006/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.

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1. Apply a 5 mm (0.20 in) bead of sealant GM P/N 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 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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
8. Install the bottom bolt on the left side until snug. Tighten 8.1. Tighten the oil pan-to-front cover bolts to 25 N.m (18 lb ft). 8.2. Tighten the oil pan-to-rear cover bolts to 12 N.m (106 lb in). 8.3. 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 in to 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. If equipped, install the oil pan skid plate.
17. Install the oil pan skid plate bolts. Tighten Tighten the bolts to 20 N.m (15 lb ft).
18. Install the transmission cover bolt. Tighten Tighten the bolt to 12 N.m (106 lb in).
19. Raise the front drive axle into position.
20. If equipped with 4WD, install the differential carrier upper mounting bolt and nut until snug. Do not tighten at this time.
21. If equipped with 4WD, install the differential carrier lower mounting bolt and nut. Tighten Tighten the bolts to 100 N.m (75 lb ft).
22. If equipped with 4WD, install the inner axle housing washers and nuts to the bracket. Tighten Tighten the nuts to 100 N.m (75 lb ft).
23. Remove the jack from the front drive axle.
24. Install new engine oil and a new oil filter. Refer to «ENGINE OIL AND OIL FILTER REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Engine Oil Pressure Sensor and/or Switch Replacement

Tools Required

J 41712 Oil Pressure Switch Socket

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1. If necessary, remove the engine sight shield. Refer to «Engine Sight Shield Replacement (4.8L, 5.3L, and 6.0L (RPO LQ4))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Sight Shield Replacement (6.0L (RPO LQ9))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Disconnect the oil pressure sensor electrical connector (1).
3. Using J 41712 or equivalent, remove the oil pressure sensor.

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1. Apply sealant GM P/N 12346004, (Canadian P/N 10953480), or equivalent, to the threads of the oil pressure sensor. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
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. If necessary, install the engine sight shield. Refer to «Engine Sight Shield Replacement (4.8L, 5.3L, and 6.0L (RPO LQ4))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Sight Shield Replacement (6.0L (RPO LQ9))»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

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1. Drain the engine oil. Refer to «ENGINE OIL AND OIL FILTER REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/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.

Note. Refer to FASTENER NOTICE in Cautions and Notices.

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1. Install the oil level sensor to the oil pan. Tighten Tighten the 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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

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1. Remove the oil pan. Refer to «Oil Pan Replacement»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Remove the engine front cover. Refer to «Engine Front Cover Replacement»(/chevrolet/avalanche/i-2001-2006/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. If required, clean and inspect the oil pump. Refer to «OIL PUMP CLEANING AND INSPECTION»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__oil-pump-cleaning-and-inspection) .

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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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
3. Install the oil pump bolts. Tighten Tighten the 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 9.1. Tighten the bolt to 12 N.m (106 lb in). 9.2. Tighten the nuts to 25 N.m (18 lb ft).
10. Install the engine front cover. Refer to «Engine Front Cover Replacement»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-front-cover-replacement) .
11. Install the oil pan. Refer to «Oil Pan Replacement»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Timing Chain and Sprockets Replacement

Tools Required

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

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1. Remove the oil pump. Refer to «OIL PUMP, PUMP SCREEN AND DEFLECTOR REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
2. Rotate the crankshaft until the timing marks on the crankshaft and the camshaft sprockets are aligned. NOTE: 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. If required, clean and inspect the timing chain and sprockets. Refer to «TIMING CHAIN AND SPROCKETS CLEANING AND INSPECTION»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

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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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
8. Install the camshaft sprocket bolts. Tighten Tighten the bolts to 35 N.m (26 lb ft).
9. Install the oil pump. Refer to «OIL PUMP, PUMP SCREEN AND DEFLECTOR REPLACEMENT»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

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1. Raise the hood to the service position, perform the following: Remove the hood hinge bolts (1). Raise the hood until vertical. Install the hood hinge bolts until snug in the service position (2).
2. Remove the radiator support. Refer to RADIATOR SUPPORT REPLACEMENT in BODY FRONT END.
3. Remove the front cover. Refer to «Engine Front Cover Replacement»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-front-cover-replacement) .
4. Remove the valve lifters. Refer to «Valve Lifter Replacement»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__valve-lifter-replacement) .
5. Remove the camshaft sensor bolt and sensor.
6. Rotate the crankshaft until the timing marks on the crankshaft and camshaft sprockets are aligned.
7. Remove the camshaft sprocket bolts. NOTE: 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.
8. Remove the camshaft sprocket and reposition the timing chain.
9. Remove the camshaft retainer bolts and retainer. NOTE: 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.
10. Remove the camshaft. 10.1. 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. 10.2. Using the bolts as a handle, carefully rotate and pull the camshaft out of the engine block. 10.3. Remove the three bolts from the camshaft.
11. If required, clean and inspect the camshaft and bearings. Refer to «CAMSHAFT AND BEARINGS CLEANING AND INSPECTION»(/chevrolet/avalanche/i-2001-2006/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.

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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. NOTE: 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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices. 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.
5. Install the camshaft retainer and bolts. Tighten Tighten the 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 bolt to 25 N.m (18 lb ft).
11. Install the valve lifters. Refer to «Valve Lifter Replacement»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__valve-lifter-replacement) .
12. Install the front cover. Refer to «Engine Front Cover Replacement»(/chevrolet/avalanche/i-2001-2006/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
14. Remove the hood hinge bolts from the service position (2).
15. Lower the hood to the normal position.
16. Install the hood hinge bolts. Tighten Tighten the bolts to 25 N.m (18 lb ft).

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1. Remove the automatic transmission. Refer to TRANSMISSION REPLACEMENT in Automatic Transmission - 4L60-E or TRANSMISSION REPLACEMENT in Automatic Transmission - 4L80-E. Important: Note the position and direction of the engine flywheel before removal.
2. Remove the flywheel bolts.
3. Remove the flywheel.
4. Install two M11x1.5 mm bolts (1) to the threaded holes of the spacer, if applicable.
5. Rotate the bolts clockwise to remove the spacer.
6. 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 (6.0L) require a spacer and longer bolts for proper flywheel position.

Scheme 345

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1. Install the spacer, if applicable, onto the rear of the crankshaft.
2. Install the flywheel and bolts 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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
4. Tighten the flywheel bolts. Tighten 4.1. Tighten the bolts a first pass in sequence to 20 N.m (15 lb ft). 4.2. Tighten the bolts a second pass in sequence to 50 N.m (37 lb ft). 4.3. Tighten the bolts a final pass in sequence to 100 N.m (74 lb ft).
5. Install the automatic transmission. Refer to TRANSMISSION REPLACEMENT in Automatic Transmission - 4L60-E or TRANSMISSION REPLACEMENT in Automatic Transmission - 4L80-E.

Tools Required

1. J 41798 Engine Lifting Brackets
2. J 21366 Converter Holding Strap

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1. Open the hood.
2. Place fender covers over both fenders.
3. Raise the hood to the service position, then perform the following: 3.1. Remove the hood hinge bolts (1). 3.2. Raise the hood until vertical. 3.3. Install the hood hinge bolts until snug in the service position (2).
4. Remove the air conditioning (AC) compressor. Refer to COMPRESSOR REPLACEMENT (LR4, LM7, AND LQ4) in HVAC Systems - Manual.
5. Remove the radiator supports. Refer to RADIATOR SUPPORT REPLACEMENT in Body Front End.
6. Reposition the radiator inlet hose clamp at the water pump.
7. Remove the radiator inlet hose from the water pump.
8. Reposition the radiator outlet hose clamp at the water pump.
9. Remove the radiator outlet hose from the water pump.
10. Remove the heater hoses. Refer to HEATER HOSE REPLACEMENT - INLET (UTILITY LR4, LM7, LQ4) or HEATER HOSE REPLACEMENT - INLET (AVALANCHE/XIT LR4, LM7, LQ4) or HEATER HOSE REPLACEMENT - OUTLET (UTILITY LR4, LM7, LQ4) or HEATER HOSE REPLACEMENT - OUTLET (AVALANCHE/XIT LR4, LM7, LQ4) in Heating, Ventilation, and Air Conditioning.
11. If equipped with the 4.8L, 5.3L, or 6.0L regular production option (RPO) LQ4, loosen the intake manifold sight shield bolt.
12. Remove the sight shield from the retainer.
13. If equipped with the 6.0L with RPO LQ9, perform the following: 13.1. Loosen the intake manifold sight shield bolt. 13.2. Loosen the left fuel rail cover bolts. 13.3. Remove the left fuel rail cover. 13.4. Loosen the right fuel rail cover bolts. 13.5. Remove the right fuel rail cover. 13.6. Remove the sight shield from the retainer.
14. Disconnect the following electrical connectors: Evaporative emissions (EVAP) canister purge solenoid (1) Generator (3) Electronic throttle control (ETC)
15. Remove the harness bracket nut (2) in order to remove the engine harness from the intake manifold.
16. Reposition the vent inlet hose clamp at the throttle body.
17. Remove the radiator vent inlet hose from the throttle body.
18. Remove the generator cable from the generator, perform the following: 18.1. Slide the boot down revealing the terminal stud. 18.2. Remove the generator cable nut from the terminal stud. 18.3. Remove the generator cable.
19. Disconnect the main coil harness (2) and fuel injector (3) electrical connectors on the left side.
20. Disconnect the following electrical connectors: The main coil harness (1) The fuel injectors (3)
21. Disconnect the manifold absolute pressure (MAP) sensor (1) and knock sensor (2) electrical connectors.
22. Remove the harness ground bolt.
23. Reposition the harness ground and negative battery cable from the block.
24. Disconnect the following electrical connectors: The coolant temperature sensor (1) The electronic variable orifice switch (2)
25. Remove the harness ground bolt at the right rear of the engine block.
26. Reposition the harness ground, and auxiliary negative battery cable, if equipped from the block.
27. Remove the harness ground bolt at the left rear of the engine block
28. Reposition the harness ground, and engine ground strap from the block.
29. Disconnect the following electrical connectors: The oil pressure sensor (1) The camshaft position (CMP) sensor (2)
30. Unclip all of the engine harness clips from the engine.
31. Remove the battery cable junction block from the junction block bracket.
32. 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.
33. Disconnect the fuel pipes. Refer to «FUEL LINE DISCONNECT FITTINGS»(/chevrolet/avalanche/i-2001-2006/remont/removal-installation/#engine-controls-removal-installation__fuel-line-disconnect-fittings) in Engine Controls - 4.8L, 5.3L, and 6.0L.
34. Raise the vehicle.
35. Disconnect the following electrical connectors: The crankshaft position (CKP) sensor (1) The engine oil level sensor (6) The coolant heater, if equipped
36. Remove the battery cable channel bolt.
37. Slide the channel pin out of the oil pan tab.
38. Gather all branches of the engine wiring harness and reposition off to the side.
39. Lower the vehicle.
40. Remove the rear power steering pump-to-engine block bolt.
41. Remove the generator bracket mounting bolts.
42. Position the bracket aside.
43. Remove the vacuum brake booster hose.
44. Remove the ignition coil, as required for the proper fit of the J 41798 before lifting the engine. Refer to Ignition Coil(s) Replacement in Engine Controls - 4.8L, 5.3L and 6.0L. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
45. Install the J 41798 to the cylinder heads. Tighten Tighten the M8 engine lift bracket bolts to 25 N.m (18 lb ft). Tighten the M10 engine lift bracket bolts to 50 N.m (37 lb ft).
46. Remove the left and right engine mount-to-engine mount bracket bolts.
47. Raise and suitably support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/chevrolet/avalanche/i-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
48. Remove the engine shield bolts and shield.
49. Remove the oil pan skid plate bolts and plate, if equipped.
50. Drain the engine oil.
51. Remove the starter motor. Refer to STARTER MOTOR REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES) in Engine Electrical.
52. Remove the catalytic converter. Refer to CATALYTIC CONVERTER REPLACEMENT (4.8L AND 5.3L ENGINES) or CATALYTIC CONVERTER REPLACEMENT (6.0L AND 8.1L ENGINES) in Engine Exhaust.
53. Remove the positive battery cable clip bolt and clip.
54. Remove the flywheel to torque converter bolts.
55. Remove the transmission oil level indicator tube nut, if equipped.
56. Remove the transmission oil level indicator tube, if equipped.
57. If equipped with the 4L60-E automatic transmission, remove the transmission bolt and stud on the right side.
58. If equipped with the 4L80-E automatic transmission, remove the transmission converter cover bolts.
59. Remove the automatic transmission bolt/studs, if equipped.
60. Separate the engine from the automatic transmission. Install the J 21366 to the transmission in order to hold the torque converter.
61. Lower the vehicle.
62. Install an engine hoist to the J 41798 .
63. Install a floor jack under the transmission for support. NOTE: 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.
64. Remove the engine.
65. Install the engine to an engine stand.
66. Remove the engine hoist.
67. Remove the J 41798 from the engine.

Note. Refer to FASTENER NOTICE in Cautions and Notices.

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1. Install the J 41798 to the engine. Tighten Tighten the M8 engine lift bracket bolts to 25 N.m (18 lb ft). Tighten the M10 engine lift bracket bolts to 50 N.m (37 lb ft).
2. Install an engine hoist to the J 41798 .
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 41798 from the engine.
11. Install the ignition coils and the spark plug wires. Refer to Ignition Coil(s) Replacement in Engine Controls - 4.8L, 5.3L and 6.0L.
12. Raise the vehicle.
13. Remove the J 21366 from the transmission.
14. Install the automatic transmission bolt/studs.
15. If equipped with the 4L80-E automatic transmission, install the transmission converter cover bolts.
16. 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).
17. Install the automatic transmission oil level indicator tube.
18. Install the automatic transmission oil level indicator tube nut. Tighten Tighten the nut to 18 N.m (13 lb ft).
19. Install the flywheel to torque converter bolts. Tighten If equipped with a 4L60E transmission, tighten the bolts to 63 N.m (47 lb ft). If equipped with a 4L80E transmission, tighten the bolts to 60 N.m (44 lb ft).
20. Install the positive battery cable clip and bolt. Tighten Tighten the bolt to 9 N.m (80 lb in).
21. Install the catalytic converter. Refer to CATALYTIC CONVERTER REPLACEMENT (4.8L AND 5.3L ENGINES) or CATALYTIC CONVERTER REPLACEMENT (6.0L AND 8.1L ENGINES) in Engine Exhaust.
22. Install the starter motor. Refer to STARTER MOTOR REPLACEMENT (4.8L, 5.3L, AND 6.0L ENGINES) in Engine Electrical.
23. Install the oil pan skid plate and bolts, if equipped. Tighten Tighten the bolts to 20 N.m (15 lb ft).
24. Install the engine shield and bolts. Tighten Tighten the bolts to 20 N.m (15 lb ft).
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 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. Install the battery cable junction block to the junction block bracket.
40. Clip all of the engine wiring harness clips to their correct location.
41. Connect the following electrical connectors: The oil pressure sensor (1) The CMP sensor (2)
42. Position the harness ground and the engine ground strap to the block.
43. Install the harness ground bolt at the left rear of the engine block.
44. Position the harness ground, and auxiliary negative battery cable, if equipped to the block.
45. Install the harness ground bolt at the right rear of the engine block. Tighten Tighten the bolts to 16 N.m (12 lb ft).
46. Connect the following electrical connectors: The coolant temperature sensor (1) The electronic variable orifice switch (2)
47. Position the harness ground and negative battery cable to the block.
48. Install the harness ground bolt. Tighten Tighten the bolt to 25 N.m (18 lb ft).
49. Connect the MAP sensor (1) and knock sensor (2) electrical connectors.
50. Connect the following electrical connectors: The main coil harness (1) The fuel injectors (3)
51. Connect the main coil harness (2) and fuel injector (3) electrical connectors on the left side.
52. Install the generator cable to the generator, perform the following: 52.1. Install the generator cable. 52.2. Install the generator cable nut to the terminal stud. Tighten Tighten the nut to 9 N.m (80 lb in). 52.3. 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 nut to 5 N.m (44 lb in).
56. Connect the following electrical connectors: The EVAP canister purge solenoid (1) The Generator (3) The ETC
57. If equipped with the 6.0L with RPO LQ9, perform the following: 57.1. Install the right fuel rail cover. 57.2. Tighten the right fuel rail cover bolts. Tighten Tighten the bolts to 9 N.m (80 lb in). 57.3. Install the left fuel rail cover. 57.4. Tighten the left fuel rail cover bolts. Tighten Tighten the bolts to 9 N.m (80 lb in). 57.5. Install the sight shield to the retainer. 57.6. Tighten the intake manifold sight shield bolt. Tighten Tighten the bolt to 9 N.m (80 lb in).
58. If equipped with the 4.8L, 5.3L, or 6.0L with RPO LQ4, install the engine sight shield to the retainer.
59. Tighten the engine sight shield bolt. Tighten Tighten the bolt to 10 N.m (89 lb in).
60. Install the heater hoses. Refer to HEATER HOSE REPLACEMENT - INLET (UTILITY LR4, LM7, LQ4) or HEATER HOSE REPLACEMENT - INLET (AVALANCHE/XIT LR4, LM7, LQ4) or HEATER HOSE REPLACEMENT - OUTLET (UTILITY LR4, LM7, LQ4) or HEATER HOSE REPLACEMENT - OUTLET (AVALANCHE/XIT LR4, LM7, LQ4) in Heating, Ventilation and Air Conditioning.
61. Install the radiator outlet hose to the water pump.
62. Position the radiator outlet hose clamp at the water pump.
63. Install the radiator inlet hose to the water pump.
64. Position the radiator inlet hose clamp at the water pump.
65. Install the radiator supports. Refer to RADIATOR SUPPORT REPLACEMENT in Body Front End.
66. Install the A/C compressor. Refer to COMPRESSOR REPLACEMENT (LR4, LM7, AND LQ4) in HVAC System - Manual.
67. Remove the hood hinge bolts from the service position (2).
68. Lower the hood to the normal position.
69. Install the hood hinge bolts. Tighten Tighten the bolts to 25 N.m (18 lb ft).
70. Remove the fender covers.
71. Perform the engine prelubing procedure. Refer to «ENGINE PRELUBING»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__engine-prelubing) .
72. Perform the CKP system variation learn procedure. Refer to «CKP SYSTEM VARIATION LEARN PROCEDURE»(/chevrolet/avalanche/i-2001-2006/remont/removal-installation/#engine-controls-removal-installation__ckp-system-variation-learn-procedure) in Engine Controls - 4.8L, 5.3L, and 6.0L. Important: After an overhaul, the engine should be tested. Use the following procedure after the engine is installed in the vehicle. 72.1. Disable the ignition system. 72.2. Crank the engine several times. Listen for any unusual noises or evidence that parts are binding. 72.3. Enable the ignition system. 72.4. Start the engine and listen for unusual noises. 72.5. Check the vehicle oil pressure gauge or light and confirm that the engine has acceptable oil pressure. 72.6. Run the engine speed at about 1,000 RPM until the engine has reached normal operating temperature. 72.7. Listen for sticking lifter and other unusual noises. 72.8. Inspect for fuel, oil and/or coolant leaks while the engine is running. 72.9. Perform a final inspection for the proper engine oil and coolant levels.
73. 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.

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1. Open the hood.
2. Remove the oil fill cap.
3. Raise and suitably support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(/chevrolet/avalanche/i-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche__lifting-and-jacking-the-vehicle) in General Information.
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.

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1. Lubricate the oil filter seal with clean engine oil. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
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.

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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

Note. Refer to FASTENER NOTICE in Cautions and Notices.

Scheme 421

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.

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Scheme 423

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.

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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 427

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 it is not cut or damaged.
4. Remove the O-ring seal from the tube, if required.

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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.

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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.

Scheme 432

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.

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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

Note. Remove the fuel rail assembly carefully in order to prevent damage to the injector electrical connector terminals and the injector spray tips. Support the fuel rail after the fuel rail is removed in order to avoid damaging the fuel rail components. Cap the fittings and plug the holes when servicing the fuel system in order to prevent dirt and other contaminants from entering open pipes and passages.

Scheme 435

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 436

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.

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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 evaporative emission (EVAP) solenoid (3), bolt (2), and isolator (1).
5. Remove the intake manifold bolts.
6. Remove the intake manifold with gaskets.
7. Separate the intake manifold-to-cylinder head gaskets (1) from the manifold.
8. Discard the intake manifold gaskets.

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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).

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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.

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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 they are not damaged.

Valve Rocker Arm Cover Removal - Right

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

Do not remove the oil fill tube from the cover unless service is required.

If the oil fill tube has been removed from the cover, install a NEW tube during assembly.

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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 they are not damaged.
7. Remove the oil fill cap from the oil fill tube.
8. Remove the oil fill tube, if required.
9. Discard the oil fill tube.

Valve Rocker Arm and Push Rod Removal

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

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

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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. NOTE: 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.

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Scheme 463

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. NOTE: 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

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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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) .

Scheme 467

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Scheme 469

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 470

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Scheme 475

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 476

Scheme 477

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 478

Scheme 479

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 480

Scheme 481

Scheme 482

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

Note. 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.

Scheme 483

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Scheme 486

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 487

Scheme 488

Scheme 489

1. Remove the camshaft sensor bolt and the sensor.
2. Remove the camshaft retainer bolts and the retainer. NOTE: 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. 3.1. Install the 3 M8-1.25 x 100 mm bolts in the camshaft front bolt holes. 3.2. Using the bolts as a handle, carefully rotate and pull the camshaft out of the engine block. 3.3. 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 490

Scheme 491

Scheme 492

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Scheme 494

1. Use the J 24270 in order to remove the cylinder bore ring ridge, if required. 1.1. Turn the crankshaft until the piston is at the bottom of the stroke. 1.2. Place a cloth on top of the piston. 1.3. Use the J 24270 or equivalent in order to remove a cylinder ring ridge. 1.4. Turn the crankshaft so the piston is at the top of the stroke. 1.5. Remove the cloth. 1.6. 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/avalanche/i-2001-2006/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 495

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Scheme 500

Scheme 501

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. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
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. Important: 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/avalanche/i-2001-2006/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 502

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Scheme 508

Scheme 509

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

Scheme 510

1. Clean the following areas: NOTE: 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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__cleanliness-and-care) . CAUTION: Refer to «SAFETY GLASSES CAUTION»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__safety-glasses-caution) in Cautions and Notices. Dry the block with compressed air. The gasket surfaces Refer to «REPLACING ENGINE GASKETS»(/chevrolet/avalanche/i-2001-2006/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/avalanche/i-2001-2006/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 511

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.

Scheme 512

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.

Honing Procedure

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 513

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

Scheme 514

Important: Use care when handling the crankshaft. Avoid damage to the bearing surfaces or the lobes of the crankshaft position reluctor ring. Damage to the teeth of the crankshaft position reluctor ring may effect On-Board Diagnostics (OBD) II system performance.

1. Clean the crankshaft with solvent.
2. Thoroughly clean all oil passages and inspect for restrictions or burrs. CAUTION: Refer to «SAFETY GLASSES CAUTION»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__safety-glasses-caution) in Cautions and Notices.
3. Dry the crankshaft with compressed air.

Inspection Procedure

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 515

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Scheme 523

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 524

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Scheme 534

1. Remove the bearing cap M8 side bolts.
2. Remove the bearing cap M10 bolts and studs. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
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 6125-1B 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 7.1. Tighten the inner bolts (1-10) a first pass in sequence to 20 N.m (15 lb ft). 7.2. Tighten the inner bolts (1-10) a final pass in sequence to 80 degrees using the J 36660-A . 7.3. Tighten the outer bolt/studs (11-20) a first pass in sequence to 20 N.m (15 lb ft). 7.4. Tighten the outer bolt/studs (11-20) a final pass in sequence to 53 degrees using the J 36660-A . 7.5. 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. 12.1. Thrust the crankshaft forward or rearward. 12.2. 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). 12.3. 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 535

Scheme 536

Scheme 537

Scheme 538

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 3.1. Tighten the connecting rod bolts first pass to 20 N.m (15 lb ft). 3.2. 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/avalanche/i-2001-2006/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.

Scheme 539

J 43690 Rod Bearing Checking Tool

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

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)

Scheme 540

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

Scheme 541

Scheme 542

Scheme 543

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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__fastener-tightening-specifications) .
6. Install the following: 6.1. J 43690-2 (5) 6.2. J 43690-3 (4) 6.3. J 43690-101 (2) 6.4. 280310 (3) 6.5. 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 544

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 545

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

Important: Certain 6.0L LQ9 engines will use a full-floating piston and pin design. In those applications, the pin is retained in the piston by retaining clips.

Press Fit Piston Pin

Tools Required

J 24086-C Piston Pin Remover/Installer Set

Scheme 546

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Scheme 549

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. NOTE: 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.

Scheme 550

Scheme 551

1. Using piston ring pliers, remove the piston rings from the piston.
2. Remove the piston pin retaining clips.
3. Remove the pin from the piston and connecting rod.
4. 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/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) .

Piston and Pin

Important: Replace the pistons and the pins that are damaged or show signs of excessive wear.

The piston and the pin are a matched set. If service is required, replace the piston and the pin as an assembly.

Do not wire brush any part of the piston.

Scheme 552

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1. Clean the varnish from the piston and the pin with cleaning solvent.
2. Dry the piston and the pin with compressed air.
3. Clean the piston ring grooves with a suitable ring groove cleaning tool.
4. Clean the oil lubrication holes and slots.
5. Inspect the piston and the pin for the following: Cracks in the piston ring lands, the piston skirt, or the pin bosses Piston ring grooves for nicks, burrs, or warpage which may cause the piston ring to bind MINOR imperfections may be removed from the piston with a fine file. Scuffed or damaged skirts (2) Eroded areas at the top of the piston (1) Scoring to the piston pin bore (3) or the piston pin
6. For certain 6.0 L applications, inspect for bent pin retaining clips or damage to the clip groove of the piston. Important: Measurements of components should be taken with the components at normal room temperature.
7. Measure the piston ring-to-piston ring groove side clearance. 7.1. Insert the edge of the piston ring into the piston ring groove. 7.2. Roll the piston ring completely around the piston. If binding is caused by a distorted piston ring groove, MINOR ring groove imperfections may be removed with a fine file. If binding is caused by a distorted piston ring, replace the piston ring.
8. Measure the piston ring side clearance with a feeler gage.
9. If side clearance is not within specifications, try another piston ring set. «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LR4 VIN V)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LM7 VIN T)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (L59 VIN Z)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ4 VIN U)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ9 VIN N)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
10. If proper piston ring-to-piston ring groove side clearance cannot be achieved, replace the piston and pin assembly.
11. To determine piston pin-to-bore clearance, use a micrometer and measure the piston pin.
12. To determine piston pin-to-bore clearance, use an inside micrometer and measure the piston pin bore. Important: The piston and pin are a matched set. If the clearance is not within specifications, replace the piston and pin as an assembly.
13. To determine the proper piston pin-to-bore clearance, subtract the piston pin diameter from the piston pin bore diameter. Refer to «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LR4 VIN V)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LM7 VIN T)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (L59 VIN Z)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ4 VIN U)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or Engine Mechanical Specifications (LQ9 VIN N) .

Connecting Rod and Bearings

Important: The powdered metal connecting rod and cap are machined for the proper clearances. The connecting rod and the cap must be used as an assembly with no repair or modifications to either mating surface.

Do not attempt to repair the connecting rod or the cap mating surfaces. If service is required, the connecting rod and the cap must be replaced as an assembly.

Scheme 560

Scheme 561

Scheme 562

Scheme 563

Scheme 564

Scheme 565

1. Clean the connecting rod and the cap in solvent. Important: Replace the connecting rod if the bolt hole threads are damaged. Do not attempt to repair the bolt hole threads of the connecting rod.
2. Clean the connecting rod threaded bolts holes. CAUTION: Refer to «SAFETY GLASSES CAUTION»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__safety-glasses-caution) in Cautions and Notices.
3. Dry the connecting rod with compressed air.
4. Inspect the connecting rod for the following: Twisting Nicks or gouging in the bearing bore Damage to the bearing locating slots in the bearing bore Proper fit of the connecting rod and the cap mating surfaces
5. Measure the connecting rod bearing bore for out-of-round. If the measurement exceeds 0.008 mm (0.0003 in), replace the connecting rod assembly.
6. Inspect the connecting rod bearings for craters or pockets. Flattened sections on the bearing halves also indicate fatigue.
7. Inspect the connecting rod bearings for excessive scoring or discoloration.
8. Inspect the connecting rod bearings for dirt or debris imbedded into the bearing material.
9. Inspect the connecting rod bearings for improper seating indicated by bright, polished sections of the bearing.

Measuring Piston Ring End Gap

Important: Do not attempt to file the end of the piston ring for fit in the cylinder bore.

Important: Measure the piston ring in the cylinder in which the piston ring will be used.

Scheme 566

1. Place the piston ring into the cylinder bore.
2. Push the piston ring into the bore 6.5 mm (0.25 in) below the piston ring travel area.
3. Insert a feeler gage and measure the piston ring end gap. Refer to «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LR4 VIN V)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LM7 VIN T)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (L59 VIN Z)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ4 VIN U)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ9 VIN N)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .

Piston and Connecting Rod Assemble

Important

1. Assemble the piston for the specific cylinder with the connecting rod for the corresponding crankshaft journal.
2. Certain 6.0L LQ9 engines will use a full-floating piston and pin design. In those applications, the pin is retained in the piston by retaining clips.

Tools Required

1. J 24086-C Piston Pin Remover/Installer Set
2. J 24086-9 Adjustable Installer
3. J 24086-10 Piston Pin Remover/Installer Base

Scheme 567

Scheme 568

Scheme 569

Scheme 570

Scheme 571

Scheme 572

Scheme 573

1. Install fork insert J 24086-920A into fixture J 24086-10 Piston Pin Remover/Installer Base. CAUTION: Avoid contact with HOT components. Wear safety glasses and protective gloves to avoid personal injury. NOTE: Applying excessive heat to the connecting rod may damage or distort the rod. Rod temperature SHOULD NOT exceed 315°C (600°F). At this temperature the end of the connecting rod will turn a straw color upon visual inspection.
2. Use a torch and apply MILD heat to the pin end of the connecting rod. Mild heating of the connecting rod will ease in piston and pin assembly.
3. With the piston and connecting rod properly assembled, both the flat flange area of the connecting rod and the alignment mark on the top of the piston will be facing the front of the engine.
4. Assemble the piston, connecting rod and adapter J 24086-16A and install onto fixture J 24086-10 .
5. Adjust installation pin J 24086-9 to 1-8. NOTE: 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.
6. Insert pin J 24086-9 through fixture J 24086-10 and to the piston pin.
7. Press pin J 24086-9 until the installer bottoms on fixture J 24086-10 .
8. Measure the piston (1), pin (3), and connecting rod (2) for proper assembly. 8.1. Place the piston and connecting rod assembly onto a table or other flat surface. Lay the flat top of the piston (1) onto the table surface. 8.2. Slide the connecting rod (2) and pin (3) to one side and hold firmly against the inside of the piston (1). 8.3. Measure the pin (3) for proper installation. A properly installed piston pin should protrude 1.27 mm (0.05 in) from the side of the piston. Important: When installing the piston rings onto the piston, use a ring expanding plier type tool. Do not roll the piston rings into the grooves of the piston. Use caution and care to expand the piston rings only slightly larger than the outside diameter (OD) of the piston.
9. Using piston ring pliers, install the piston rings onto the piston. 9.1. Install the oil control ring spacer in the groove. 9.2. Install the lower oil control ring. The oil control rings do not have a dimple or orientation mark and may be installed in either direction. 9.3. Install the upper oil control ring. 9.4. Stagger the three oil control ring end gaps a minimum of 90 degrees. 9.5. Using piston ring pliers, install the lower compression ring. The lower compression ring has a dimple or orientation mark and must face the top of the piston. 9.6. Using piston ring pliers, install the upper compression ring. The upper compression ring does not have a dimple or orientation mark and may be installed in either direction. 9.7. Stagger the compression ring end gaps a minimum of 25 mm (1.0 in).

Full-Floating Piston Pin

Important: With the piston and connecting rod properly assembled, both the flat flange area of the connecting rod and the alignment mark on the top of the piston will be facing the front of the engine.

Scheme 574

Scheme 575

1. Install the pin to the piston and connecting rod.
2. Install the retaining clips. Important: When installing the piston rings onto the piston, use a ring expanding plier type tool. Do not roll the piston rings into the grooves of the piston. Use caution and care to expand the piston rings only slightly larger than the outside diameter (OD) of the piston.
3. Using piston ring pliers, install the piston rings onto the piston. 3.1. Install the oil control ring spacer in the groove. 3.2. Install the lower oil control ring. The oil control rings do not have a dimple or orientation mark and may be installed in either direction. 3.3. Install the upper oil control ring. 3.4. Stagger the three oil control ring end gaps a minimum of 90 degrees. 3.5. Using piston ring pliers, install the lower compression ring. The lower compression ring has a dimple or orientation mark and must face the top of the piston. 3.6. Using piston ring pliers, install the upper compression ring. The upper compression ring does not have a dimple or orientation mark and may be installed in either direction. 3.7.Stagger the compression ring end gaps a minimum of 25 mm (1.0 in).

Camshaft Bearing Removal

Tools Required

J 33049 Camshaft Bearing Service Set

Important: A loose camshaft bearing may be caused by an enlarged, out of round or damaged engine block bearing bore.

Scheme 576

Scheme 577

Scheme 578

1. Prior to bearing removal, inspect the camshaft bearings for loose fit in the engine block bearing bores. Refer to «CAMSHAFT AND BEARINGS CLEANING AND INSPECTION»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__camshaft-and-bearings-cleaning-and-inspection) .
2. Repair or replace the components as required.
3. Select the expanding driver (4-8) and washer (2 or 3) from the J 33049 .
4. Assemble the tool.
5. Insert the tool through the front of the engine block and into the bearing.
6. Tighten the expander assembly (15) nut until snug.
7. Push the guide cone (1) into the front camshaft bearing to align the tool.
8. Drive the bearing from the block bore. Important: To remove the front camshaft bearing, operate the tool from the rear of the block using the guide cone in the rear camshaft bearing bore.
9. Repeat the above procedures to remove the remaining bearings.

Scheme 579

1. The tool consists of a guide cone (1), driving washers (2 or 3), expander bearing drivers (4-8), driver bars (9 or 10), expander jaws (11), expander sleeve (12), expander cone (13), expander shaft (14), and expander assembly (15).
2. Expander bearing driver number one inside diameter is 28.575-37.465 mm (1.125-1.475 in) and is used with the expander assembly and the small washer.
3. Expander bearing driver number two inside diameter is 37.465-43.18 mm (1.475-1.7 in) and is used with number one expanding driver and the small washer.
4. Expander bearing driver number three inside diameter is 43.18-48.895 mm (1.7-1.925 in) and is used with number two expanding driver and the large washer.
5. Expander bearing driver number four inside diameter is 48.895-54.61 mm (1.925-2.15 in) and is used with number three expanding driver and the large washer.
6. Expander bearing driver number five inside diameter is 54.61-60.325 mm (2.150-2.375 in) and is used with number four expanding driver and the large washer.
7. Expander bearing driver number six inside diameter is 60.325-68.326 mm (2.375-2.69 in) and is used with number five expanding driver and the large washer.

Scheme 580

Scheme 581

1. Select the proper expanding driver and washer from the expanding driver and washer information. Important: To install or remove the expanding driver, always push on or pull from the ends. Pressure on the outside diameter may cause a bind against the rubber expanding sleeve.
2. Place the expanding driver onto the expander assembly.
3. Check to insure that the separation lines between the segments of the expanding driver align with the separation lines of the expander assembly.
4. Place the guide cone over the driving bar, with the small end of the cone facing the driver assembly.
5. Place the driving washer over the threaded portion of the expander assembly.
6. Screw the expander assembly, with driving washer, onto the driving bar. It may be necessary to install the driver bar extension for removal of the inner bearings.
7. Insert the tool into a inner camshaft bearing and tighten until snug. Operate the tool from the front or rear of the engine block. On some engine blocks the nut on the expander assembly is inaccessible except from either end. In this case you must use a socket and extension to enlarge and reduce the expander assembly.
8. Slide the nylon cone into the front or rear camshaft bearing. This will properly align the tool.
9. Drive the bearing out of or into the engine block.
10. Repeat the procedure for the additional inner bearings.
11. For the two end bearings, front and rear, remove the nylon cone and driver bar extension.
12. Drive the bearings out of or into the engine block.

Camshaft and Bearings Cleaning and Inspection

Tools Required

1. J 7872 Magnetic Base Dial Indicator Set
2. J 8520 Camshaft Lobe Lift Indicator

Scheme 582

Scheme 583

Scheme 584

Scheme 585

Scheme 586

Scheme 587

1. Clean the components in solvent. CAUTION: Refer to «SAFETY GLASSES CAUTION»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__safety-glasses-caution) in Cautions and Notices.
2. Dry the components with compressed air.
3. Inspect the camshaft bearing journals (1) for scoring or excessive wear.
4. Inspect the camshaft valve lifter lobes (2) for scoring or excessive wear.
5. Inspect the threaded bolt holes (3) in the front of the camshaft for damaged threads or debris.
6. Inspect the camshaft sprocket pin (4) for damage.
7. Inspect the camshaft position reluctor ring for nicks or damage.
8. Inspect the camshaft retainer plate for wear or a damaged sealing gasket. If the camshaft retainer plate sealing gasket is not cut or damaged, it may be used again.
9. Inspect the camshaft bearings for proper fit in the engine block. Camshaft bearings have an interference fit to the engine block and should not be loose in their engine block bearing bores.
10. Inspect the camshaft bearings for excessive wear or scoring. Bearings with excessive scoring or wear must be replaced.
11. Measure the camshaft journals for wear and out-of-round with a micrometer. If the camshaft bearing journals are more than 0.025 mm (0.001 in) out-of-round, replace the camshaft. If the camshaft bearing journal diameter is less that 54.99 mm (2.164 in), replace the camshaft.
12. Measure the camshaft lobes for wear with a micrometer. A 4.8/5.3L camshaft with an intake lobe that measures 46.169 mm (1.817 in) or less must be replaced. A 4.8/5.3L camshaft with an exhaust lobe that measures 46.199 mm (1.818 in) or less must be replaced. A 6.0L camshaft with an intake lobe that measures 46.31 mm (1.823 in) or less must be replaced. A 6.0L camshaft with an exhaust lobe that measures 46.48 mm (1.83 in) or less must be replaced.
13. Measure the camshaft runout. 13.1. Mount the camshaft in wooden V blocks or between centers on a fixture. 13.2. Check the runout of the intermediate camshaft bearing journals using the J 7872 . 13.3. If camshaft runout exceeds 0.05 mm (0.002 in), the camshaft is bent and should be replaced.

Measuring Camshaft Lobe Lift

Important: Measuring camshaft lobe lift is a procedure used to determine if the camshaft lobes have worn.

This test is to be performed prior to engine disassembly and with the camshaft and valve train components installed in the engine.

Scheme 588

1. Measure camshaft lobe lift using J 8520 .
2. Remove the valve rocker arms and bolts
3. Install the dial indicator mounting stud into the valve rocker arm bolt hole.
4. Assemble the components of the J 8520 and position onto the stud.
5. Position the shaft of the dial indicator onto the end of the pushrod.
6. Rotate the face of the dial indicator to zero.
7. Slowly rotate the crankshaft clockwise until the dial indicator obtains its highest and lowest readings.
8. Compare the total lift shown to specifications: The proper lobe lift for 4.8/5.3L intake lobes is 6.82 mm (0.268 in). The proper lobe lift for 4.8/5.3L exhaust lobes is 6.96 mm (0.274 in). The proper lobe lift for 6.0L intake lobes is 6.96 mm (0.274 in). The proper lobe lift for 6.0L exhaust lobes is 7.13 mm (0.281 in).

Camshaft Bearing Installation

Tools Required

J 33049 Camshaft Bearing Service Set

Important: A loose camshaft bearing may be caused by an enlarged, out of round or damaged engine block bearing bore.

Scheme 589

Scheme 590

Scheme 591

1. Prior to bearing removal, inspect the camshaft bearings for loose fit in the engine block bearing bores.
2. Repair or replace the components as required.
3. Select the expanding driver (4-8) and washer (2 or 3) from the J 33049 . Refer to «CAMSHAFT BEARING REMOVAL»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__camshaft-bearing-removal) .
4. Assemble the tool.
5. Insert the tool through the front of the engine block and into the bearing.
6. Tighten the expander assembly nut until snug.
7. Push the guide cone into the front camshaft bearing to align the tool.
8. Drive the bearing from the block bore. Important: To remove the front camshaft bearing, operate the tool from the rear of the block using the guide cone in the rear camshaft bearing bore.
9. Repeat the above procedures to remove the remaining bearings.

Scheme 592

Scheme 593

Scheme 594

1. Clean the components with cleaning solvent. CAUTION: Refer to «SAFETY GLASSES CAUTION»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__safety-glasses-caution) in Cautions and Notices.
2. Dry the components with compressed air.
3. Inspect the timing chain for binding or wear.
4. Inspect the camshaft and crankshaft sprockets for: Worn teeth (1) Damaged teeth (2) Chipped teeth (3) Worn valleys between the sprocket teeth
5. Inspect the crankshaft sprocket keyway for wear.
6. Inspect the crankshaft sprocket oil pump drive splines for wear.

Valve Rocker Arm and Push Rods Cleaning and Inspection

Important: Parts that are to be used again must be marked, sorted or organized for assembly.

Scheme 595

Scheme 596

Scheme 597

1. Mark, sort, or organize the components for assembly. Refer to «SEPARATING PARTS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) .
2. Clean the components with cleaning solvent. CAUTION: Refer to «SAFETY GLASSES CAUTION»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__safety-glasses-caution) in Cautions and Notices.
3. Dry the components with compressed air.
4. Inspect the valve rocker arms bearings (2) for binding or roughness.
5. Inspect the valve rocker arm pushrod sockets (3) and valve stem mating surfaces (1). These surfaces should be smooth with no scoring or exceptional wear.
6. Inspect the pushrod for worn or scored ends. These surfaces should be smooth with no scoring or exceptional wear.
7. Inspect the pushrod for bends. Roll the pushrod on a flat surface to determine if the pushrod is bent.
8. Inspect the pushrod oil passages for restrictions.
9. Inspect the pivot supports for cracks, wear, or other damage.

Valve Lifters and Guides Cleaning and Inspection

Important: Components that are to be used again must be marked, sorted or organized for assembly.

Scheme 598

Scheme 599

1. Mark, sort, or organize the components for assembly. Refer to «SEPARATING PARTS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) .
2. Clean the components in cleaning solvent. CAUTION: Refer to «SAFETY GLASSES CAUTION»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__safety-glasses-caution) in Cautions and Notices.
3. Dry the components with compressed air.
4. Inspect the valve lifters for the following: Bent or broken clip (1) Worn pushrod socket (2) Scuffed or worn sides (3) If the valve lifter shows wear, inspect the engine block lifter bores for wear or damage. Flat spots on the roller (4) Loose or damaged pin (5) Plugged oil hole (6) Worn or damaged roller bearing The roller should rotate freely with no binding or roughness.
5. Inspect the valve lifter guides for the following: For cracks or damage Excessive wear in the lifter mounting bores

Cylinder Head Disassemble

Tools Required

J 8062 Valve Spring Compressor-Head Off

Important

1. Remove the spark plugs from the cylinder head with the components at room temperature.
2. Mark, organize, or sort the cylinder head components for assembly. Return the components to their original location during assembly.
3. Do not remove the cylinder head expansion plugs (7), unless service is required.

Scheme 600

Scheme 601

Scheme 602

Scheme 603

Scheme 604

Scheme 605

1. Remove the spark plugs from the cylinder heads.
2. Use the J 8062 in order to compress the valve spring.
3. Remove the valve stem keys (2).
4. Remove the valve spring cap (3).
5. Remove the valve spring (4).
6. Remove the valves (9 and 10).
7. Remove the valve stem oil seal and shim assembly (5). Refer to «SEPARATING PARTS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) .
8. Remove the cylinder head expansion plugs (1), if required.
9. Remove the coolant sensor from the left cylinder head, if required.
10. Remove the coolant plug from the right cylinder head, if required.

Cylinder Head Cleaning and Inspection

Tools Required

1. J 8089 Carbon Removal Brush
2. J 9666 Valve Spring Tester

Important: When cleaning a cylinder head in a thermal type oven, do not exceed 204°C (400°F).

Scheme 606

Scheme 607

Scheme 608

Scheme 609

Scheme 610

1. Clean the following components: CAUTION: Refer to «SAFETY GLASSES CAUTION»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__safety-glasses-caution) in Cautions and Notices. Important: Be careful not to scuff the chamber. Use the J 8089 in order to remove the carbon from the combustion chambers. Gasket surfaces Refer to «REPLACING ENGINE GASKETS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__replacing-engine-gaskets) . Valve stems and heads on a buffing wheel Bolt hole threads Remove all dirt, debris, or threadlocking material from the bolt holes.
2. Inspect the following: 2.1. Worn or loose valve seats (8 or 11) 2.2. The cylinder head for cracks in the exhaust ports and combustion chambers 2.3. The cylinder head for external cracks in the water chambers 2.4. The gasket surfaces for excessive scratches or gouging Refer to «REPLACING ENGINE GASKETS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__replacing-engine-gaskets) . 2.5. The bolt hole threads for debris or damaged threads Refer to «THREAD REPAIR»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__thread-repair) or «Thread Repair Specifications»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
3. Inspect the cylinder head for warpage. Refer to «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LR4 VIN V)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LM7 VIN T)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (L59 VIN Z)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ4 VIN U)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ9 VIN N)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
4. Inspect the valve springs for squareness.
5. Use the J 9666 in order to measure the valve spring tension. Replace the spring if the spring tension is less than 310 N (70 lb) at 45.75 mm (1.80 in).

Valve Guide Reaming/Valve and Seat Grinding

Tools Required

J 37378-1 Valve Guide Reamer

Valve Guide Reaming

Important

1. Excessive valve stem-to-guide clearance may cause a noisy valve train, premature valve stem oil seal wear, component damage, and/or excessive engine oil consumption.
2. Insufficient valve stem-to-guide clearance will result in noisy or sticking valves. Valves that are too tight may disturb engine smoothness or lead to component damage.

Scheme 611

Scheme 612

Scheme 613

Scheme 614

Scheme 615

1. Measure the valve stem-to-guide clearance using a dial indicator. Position the tip of the dial indicator at the top of the valve guide. Valve stem-to-guide clearance may also be obtained by using a micrometer to measure the valve stem diameter and a ball type measuring gage to measure the guide bore.
2. A valve stem (1) and guide (2) with excessive clearance must be replaced or the components replaced. Refer to «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LR4 VIN V)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LM7 VIN T)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (L59 VIN Z)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ4 VIN U)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) or «Engine Mechanical (4.8L, 5.3L, And 6.0L) Specifications (LQ9 VIN N)»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
3. Inspect the valve stems for excessive scoring, wear, or warpage. A valve stem that has excessive scoring (3 or 4) or wear (4 or 6) must be replaced. A valve guide that is worn and has excessive stem-to-guide clearance should be reamed and valves with oversize stems installed.
4. Measure the valve stem diameter. A valve stem with a diameter less than 7.95 mm (0.313 in) must be replaced. If the valve stem diameter is within specifications, and the stem-to-guide clearance is excessive, the valve guide must be reamed oversize and a valve with oversize stem installed.
5. Ream the valve guide using the J 37378-1 .
6. Clean the guide bore of all metal shavings and debris.
7. Install the valve (2), with oversize stem, into the cylinder head (1).
8. Inspect the valve for the proper fit. Move the valve back and forth in the guide. The valve should move freely with no resistance or drag.

Valve and Seat Grinding

Important

Scheme 616

1. Reconditioning the valve seats is very important. The seating of the valves must be perfect for the engine to deliver optimum power and performance. Several different types of equipment are available for grinding valve seats.
2. Another important factor is the cooling of the valve head. Good contact between the valve and the seat will ensure that heat will be properly dissipated.
3. The recommendations of the manufacturer of the equipment should be followed carefully to obtain the proper results. Regardless of what type of equipment is used, it is essential that valve guide bores be free from carbon or dirt to ensure proper centering of the tool pilot in the guide.
4. Valves that are pitted must be refaced to the proper angle. Valve stems that show excessive wear, or valves that are warped excessively must be replaced. When a valve head that is warped excessively is refaced, a knife edge may be ground on part or all of the valve head due to the amount of metal that must be removed. Knife edges lead to breakage, burning or pre-ignition due to heat localizing on this knife edge. If the edge of the valve head is less than 1.25 mm (0.05 in) after grinding, replace the valve.
5. Several different types of equipment are available for refacing valves. The recommendation of the manufacturer of the equipment should be carefully followed to obtain the proper results.
6. DO NOT reface intake valves. Intake valves with excessive wear or damage MUST be replaced.

Scheme 617

Scheme 618

Scheme 619

1. Inspect the valve for the following: Burnt or eroded areas (1) A worn margin (2) A bent stem (3) A worn or scored stem (4) A worn key groove (5) A worn stem tip (6)
2. Inspect the valve face for the following: Worn or no margin (1 or 4) Pitted surfaces (2) Burnt or eroded areas (3)
3. Inspect the valve margin. The exhaust valve may be refaced if the margin is greater than 1.25 mm (0.05 in) thick before grinding.
4. Reface pitted exhaust valves on a suitable valve refacing machine.
5. Replace the valve if the margin is less than 1.25 mm (0.05 in) thick after grinding.
6. If the valve face has been ground, it may be necessary to shim the valve spring to obtain the proper spring installed height. Refer to «CYLINDER HEAD DISASSEMBLE»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-disassemble) .
7. Inspect for a loose valve seat (8 or 11) in the cylinder head (1). The valve seat has an interference fit to the cylinder head.
8. Clean the valve guide (6) bores with a suitable tool. Remove all carbon or dirt from the bores. The valve guide must be clean for the seat grinding tool to obtain proper results.
9. Grind the valve seat. The recommendations of the manufacturer of the equipment should be followed carefully to obtain the proper results. Regardless of what type of equipment is used, it is essential that valve guide bores be free from carbon or dirt to ensure proper centering of the tool pilot in the guide.
10. Inspect the valve seats. The valve seats should be concentric to within 0.05 mm (0.0021 in) total indicator reading. If the valve seat has been ground, it may be necessary to shim the valve spring to attain the proper spring installed height. Refer to «CYLINDER HEAD DISASSEMBLE»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__cylinder-head-disassemble) .

Cylinder Head Assemble

Tools Required

J 8062 Valve Spring Compressor

Scheme 620

Scheme 621

Scheme 622

Scheme 623

Scheme 624

Scheme 625

1. Clean the cylinder head valve spring seat and/or shim area. Important: When using the valves and related components again, install the parts to their original location.
2. Install the valves (9 and 10) into the proper guides. Refer to «SEPARATING PARTS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) . Important: The valve stem oil seal alignment and position on the valve guide is critical. An improperly installed valve stem oil seal may lead to excessive oil consumption, increased vehicle emissions, or component damage.
3. Install the valve stem oil seal and shim assembly (5).
4. Install the valve spring (4).
5. Install the valve spring cap (3).
6. Compress the valve spring using the J 8062 .
7. Install the valve stem keys. 7.1. Use grease to hold the keys in place and remove the J 8062 . 7.2. Make sure the keys seat properly in the groove of the valve stem. 7.3. Tap the end to the valve stem with a plastic faced hammer to seat the keys, if necessary.
8. Measure the valve spring installed height using a ruler. Measure from the base of the spring to the top of the spring. If the installed height exceeds 46.25 mm (1.82 in), install a valve seat spring shim of approximately 0.5 mm (0.02 in) thick. Do not shim the valve spring to obtain less than the specified height. Do not assemble the components without a spring shim on the cylinder head, aluminum head.
9. Install the remaining valves, springs, and other components.
10. Install sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent to the threads of the coolant sensor. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
11. Install the coolant sensor into the left cylinder head. Tighten Tighten the coolant sensor to 20 N.m (15 lb ft).
12. Install the coolant plug to the right cylinder head. Tighten Tighten the coolant plug to 20 N.m (15 lb ft).
13. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the sides of the cylinder head expansion plugs (1), if applicable.
14. Install the expansion plugs into the cylinder head, aluminum head. A properly installed plug should be slightly below flush with the face of the head.

Oil Pump Disassemble

Important: The internal parts of the oil pump assembly are not serviced separately, excluding the spring. If the oil pump components are worn or damaged, replace the oil pump as an assembly.

Scheme 626

Scheme 627

Scheme 628

Scheme 629

Scheme 630

Scheme 631

Scheme 632

1. Remove the oil pump cover bolts.
2. Remove the oil pump cover. Important: Mark or identify the gears for assembly. Refer to «SEPARATING PARTS»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__separating-parts) .
3. Remove the drive gear.
4. Remove the driven gear.
5. Remove the pressure relief valve plug.
6. Remove the pressure relief valve spring.
7. Remove the pressure relief valve.
8. Inspect the oil pump components. Refer to «OIL PUMP CLEANING AND INSPECTION»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l__oil-pump-cleaning-and-inspection) .

Oil Pump Cleaning and Inspection

Important: The internal parts of the oil pump assembly are not serviced separately, excluding the spring. If the oil pump components are worn or damaged, replace the oil pump as an assembly.

The oil pump pipe and screen are to be serviced as an assembly. Do not attempt to repair the wire mesh portion of the pump and screen assembly.

Scheme 633

Scheme 634

Scheme 635

Scheme 636

Scheme 637

Scheme 638

1. Clean the parts in solvent. CAUTION: Refer to «SAFETY GLASSES CAUTION»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__safety-glasses-caution) in Cautions and Notices.
2. Dry the parts with compressed air.
3. Inspect the oil pump housing and the cover for cracks, excessive wear, scoring, or casting imperfections.
4. Inspect the oil pump housing-to-engine block oil gallery surface for scratches or gouging.
5. Inspect the oil pump housing for damaged bolt hole threads.
6. Inspect the relief valve plug and plug bore for damaged threads.
7. Inspect the oil pump internal oil passages for restrictions.
8. Inspect the drive gear and driven gear for chipping, galling or wear. Minor burrs or imperfections on the gears may be removed with a fine oil stone.
9. Inspect the drive gear splines for excessive wear.
10. Inspect the pressure relief valve and bore for scoring or wear. The valve must move freely in the bore with no restrictions.
11. Inspect the oil pump screen for debris or restrictions.
12. Inspect the oil pump screen for broken or loose wire mesh.

Oil Pump Assemble

Important: Prior to assembling the oil pump, coat all wear or internal surfaces with clean engine oil.

Scheme 639

Scheme 640

Scheme 641

Scheme 642

Scheme 643

Scheme 644

Scheme 645

1. Install the driven gear into the pump housing. Install the driven gear with the orientation mark facing the pump cover.
2. Install the drive gear into the pump housing.
3. Install the oil pump cover. NOTE: Refer to «FASTENER NOTICE»(/chevrolet/avalanche/i-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
4. Install the pump cover bolts. Tighten Tighten the oil pump cover bolts to 12 N.m (106 lb in).
5. Install the regulator valve.
6. Install a NEW regulator valve spring.
7. Install the pressure relief valve plug. Tighten Tighten the pressure relief valve plug to 12 N.m (106 lb in).
8. Inspect the oil pump for smoothness of operation by rotating the drive gear.

Engine Front Cover Cleaning and Inspection

Important

1. Do not use the crankshaft oil seal again. Install a NEW crankshaft oil seal during assembly.
2. Do not use the front cover-to-engine block gasket again. Install a NEW gasket during assembly.

Scheme 646