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.
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.
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.
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.
10. Inspection of the fasteners can eliminate the possibility that a incorrect bolt, nut, spacer, or washer was installed.
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.
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.

Scheme 94

Scheme 94: Test Description

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
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.
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.
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.
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.
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.
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.

Scheme 95

Scheme 95: Test Description

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.
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.

Scheme 96

Scheme 96: Test Description

2. This test is to verify that the symptom is present during diagnosing. Other vehicle components may cause a similar symptom.
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.
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.
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.

Scheme 97

Scheme 97: Test Description

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.
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.
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).
6. Inspection of the fasteners can eliminate the possibility that a incorrect bolt, nut, spacer, or washer was installed.
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.
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.
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.

Scheme 98

Scheme 98: Test Description

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.
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.
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.
6. Accessory drive component brackets that are bent or cracked will also cause the drive belt(s) to fall off.
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

Scheme 99: Test Description

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).
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.
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

Scheme 100: Inspection Procedure

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.

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) .
Move the drive belt tensioner through its full travel. The movement should feel smooth. There should be no binding. The tensioner should return freely.
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) .
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) .

Scheme 101

Scheme 101: Removal Procedure

Scheme 102

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

Scheme 103

Scheme 103: Installation Procedure

Scheme 104

Scheme 105

Route the drive belt (1) around all the pulleys except the idler pulley.
Install the breaker bar with hex-head socket to the belt tensioner bolt.
Rotate the belt tensioner clockwise in order to relieve the tension on the tensioner.
Install the drive belt (1) under the idler pulley.
Slowly release the tension on the belt tensioner.
Remove the breaker bar and socket from the belt tensioner bolt.
Inspect the drive belt (1) for proper installation and alignment.
Align the arrow (2) at the throttle body end of the duct with the throttle body attaching stud (1).
Install the air cleaner outlet duct.
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.
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 106: Removal Procedure

Scheme 107

Remove the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(/chevrolet/avalanche/i-2001-2006/remont/mechanical/#engine-mechanical-48l-53l-60l) .
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.
Remove the engine shield bolts.
Remove the engine shield.
Install a ratchet into the air conditioning (A/C) belt tensioner adapter opening.
Rotate the A/C belt tensioner clockwise in order to relieve tension on the belt.
Remove the A/C belt from the pulleys.
Slowly release the tension on the A/C belt tensioner.
Remove the ratchet from the A/C belt tensioner.
Clean and inspect the belt surfaces of all the pulleys.

Scheme 108

Scheme 108: Installation Procedure

Scheme 109

Install the A/C belt around the crankshaft balancer.
Install a ratchet into the A/C drive belt tensioner adapter opening
Rotate the A/C belt tensioner clockwise in order to relieve tension on the tensioner.
Install the A/C belt over the idler pulley.
Install the A/C belt around the A/C compressor pulley.
Slowly release the tension on the A/C belt tensioner.
Remove the ratchet from the A/C belt tensioner.
Inspect the A/C belt for proper installation and alignment.
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.
Install the engine shield bolts. Tighten Tighten the bolts to 20 N.m (15 lb ft).
Lower the vehicle.
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

Scheme 110: Removal Procedure

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

Scheme 111

Scheme 111: Installation Procedure

Install the drive belt idler pulley and bolt to the generator bracket. Snug the bolt finger tight.
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.
Tighten the drive belt idler pulley bolt. Tighten Tighten the bolt to 50 N.m (37 lb ft).

Scheme 112

Scheme 112: Removal Procedure

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

Scheme 113

Scheme 113: Installation Procedure

Install the drive belt tensioner.
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.
Tighten the drive belt tensioner bolts. Tighten Tighten the bolts to 50 N.m (37 lb ft).
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

Scheme 114: Removal Procedure

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) .
Remove the A/C belt tensioner bolts.
Remove the A/C belt tensioner.

Scheme 115

Scheme 115: Installation Procedure

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.
Install the A/C belt tensioner bolts. Tighten Tighten the bolts to 50 N.m (37 lb ft)
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) .

Test Description Chevrolet Avalanche I