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DEFINITION: The following items are indications of chirping: A high pitched noise that is heard once per revolution of the drive belt or a pulley. Chirping may occur on cold damp start-ups and will subside once the vehicle reaches normal operating temp. DEFINITION: The following items are indications of drive belt squeal: A loud screeching noise that is caused by a slipping drive belt. This is unusual for a drive belt with multiple ribs. The noise occurs when a heavy load is applied to the drive belt, such as an air conditioning compressor engagement snapping the throttle, or slipping on a seized pulley or a faulty accessory drive component. DEFINITION: The following items are indications of drive belt whine: A high pitched continuous noise. The noise may be caused by an accessory drive component failed bearing. 1 Did you review the drive belt symptom operation and perform the necessary inspections? Go to Step 2 Go to Symptoms 2 Verify that there is a chirping, squeal or whine noise. Does the engine make the chirping squeal or whine noise? Go to Step 3 Go to Diagnostic 3 1. Remove the drive belt. If the engine has multiple drive belts, remove the belts one at a time and perform the test below each time a belt is removed. 2. Operate the engine for no longer than 30- 40 seconds. 3. Repeat this test if necessary by removing the remaining belts. Does the chirping, squeal or whine noise still exist? Go to Symptoms Go to Step 4
2008 Hummer H2 2008 ENGINE Engine Mechanical - 6.2L - H2
4 If diagnosing a chirping noise, inspect for severe pilling exceeding 1/3 of the belt groove depth. If diagnosing a squeal or whine noise, proceed to step 13. Do the belt grooves have pilling? Go to Step 5 Go to Step 6 5 Clean the drive belt pulleys with a suitable wire brush. Did you complete the repair? Go to Step 20 Go to Step 6 6 Inspect for misalignment of the pulleys. Are any of the pulleys misaligned? Go to Step 7 Go to Step 8 7 Replace or repair any misaligned pulleys. Did you complete the repair? Go to Step 20 Go to Step 8 8 Inspect for bent or cracked brackets. Did you find any bent or cracked brackets? Go to Step 9 Go to Step 10 9 Replace any bent or cracked brackets. Did you complete the repair? Go to Step 20 Go to Step 10 10 Inspect for improper, loose or missing fasteners. Did you find the condition? Go to Step 11 Go to Step 12 11 1. Tighten any loose fasteners. Refer to Fastener Tightening Specifications. 2. Replace any improper or missing fasteners. Did you complete the repair? NOTE: Refer to Fastener Notice . Go to Step 20 Go to Step 12 12 Inspect for a bent pulley. Did you find the condition? Go to Step 18 Go to Step 19 13 Inspect for an accessory drive component component. If diagnosing a whine noise and the condition still exist, proceed to Diagnostic Aids. Did you find and correct the condition? Go to Step 20 Go to Step 14 Test the drive belt tensioner for proper
2008 Hummer H2 2008 ENGINE Engine Mechanical - 6.2L - H2
DRIVE BELT RUMBLING AND VIBRATION DIAGNOSIS Diagnostic Aids The accessory drive components can have an affect on engine vibration. Vibration from the The drive belt may have a rumbling condition that can not be seen or felt. Sometimes replacing If replacing the drive belt, completing the diagnostic table, and the noise is only heard when the Test Description 14 operation. Refer to Drive Belt Tensioner Diagnosis. Did you find and correct the condition? Go to Step 20 Go to Step 15 15 Inspect for the correct drive belt length. Did you find and correct the condition? Go to Step 20 Go to Step 16 16 Inspect for misalignment of a pulley. Did you find and correct the condition? Go to Step 20 Go to Step 17 17 Inspect for the correct pulley size. Did you find and correct the condition? Go to Step 20 Go to Diagnostic 18 Replace the bent pulley. Did you complete the repair? Go to Step 20 Go to Step 19 19 Replace the drive belt. Refer to Drive Belt Replacement - Accessory or Air Conditioning Compressor Belt Replacement. Did you complete the repair? Go to Step 20 Go to Diagnostic 20 Operate the system in order to verify the repair. Did you correct the condition? System OK Go to Step 3
2008 Hummer H2 2008 ENGINE Engine Mechanical - 6.2L - H2
The numbers below refer to the step numbers on the diagnostic table. 2: This test is to verify that the symptom is present during diagnosing. Other vehicle 3: This test is to verify that one of the drive belts is causing the rumbling noise or vibration. 4: Inspecting the drive belts is to ensure that they are not causing the noise. Small cracks 5: Small amounts of pilling is normal condition and acceptable. When the pilling is severe 9: Inspecting of the fasteners can eliminate the possibility that the wrong bolt, nut, spacer, 11: This step should only be performed if the water pump is driven by the drive belt. Inspect 12: Accessory drive component brackets that are bent, cracked, or loose may put extra Step Action Yes No DEFINITION: The following items are indications of drive belt rumbling: A low pitch tapping, knocking, or thumping noise heard at or just above idle. Heard once per revolution of the drive belt or a pulley. Rumbling may be caused from: Pilling, the accumulation of rubber dust that forms small balls (pills) or strings in the drive belt pulley groove The separation of the drive belt A damaged drive belt NOTE: Refer to Belt Dressing Notice .
2008 Hummer H2 2008 ENGINE Engine Mechanical - 6.2L - H2
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