Diagnostic Aids
Loose or improper installation of a body component, a suspension component, or other items of the vehicle may cause a squeal noise.
If the noise is intermittent, verify which accessory drive components is making the noise by varying their loads making sure they are operated to their maximum capacity. Some of the causes of component noise can be that the A/C system is over charged, the power steering system is restricted or has incorrect fluid, or that there is an extra load on the generator.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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The noise may not be engine related. This step is to verify that the engine is making the noise. If the engine is not making the noise do not proceed further with this table
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The noise may be an internal engine noise. Removing the drive belt and operating the engine for a brief period will verify that the squeal noise is a drive belt or an accessory drive component. With the drive belt removed the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belt removed.
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This test is to verify that an accessory drive component does not have a seized bearing. With the belt removed test the bearings in the accessory drive components by turning the pulleys and verify that they turn smoothly. Also test the accessory drive components with the engine operating by varying the load on the components to verify that the components operate properly.
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This test is to verify that the drive belt tensioner operates properly. If the drive belt tensioner is not operating properly the belt may slip causing a squealing noise.
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This test is to verify that the drive belt is the correct length. If an incorrect length drive belt was installed it may not be possible to achieve the correct tension or it may not be routed properly and may be turning an accessory drive component in the wrong direction.
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Misalignment of the pulleys may be caused from improper mounting of the accessory drive component, incorrect installation of a pulley, a bent pulley or a bent pulley shaft. 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 repair procedure.
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This test is to verify that the pulleys are the correct diameter and width. Using a known good vehicle compare the pulley sizes.
Step | Action | Yes | No | ||||
|---|---|---|---|---|---|---|---|
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Notice: Do not use belt dressing on the drive belt. Belt dressing causes the breakdown of the composition of the drive belt. Failure to follow this recommendation will damage the drive belt. DEFINITION: The following items are indications of drive belt squeal:
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1 | Did you review the Drive Belt Symptom operation and perform the necessary inspections? | Go to Step 2 | |||||
Verify that there is a squeal noise. Does the engine make the squeal noise? | Go to Step 3 | Go to Diagnostic Aids | |||||
Does the noise still exist? | Go to Step 4 | ||||||
Inspect for an accessory drive component seized bearing or a faulty accessory drive component. Did you find and correct the condition? | Go to Step 9 | Go to Step 5 | |||||
Test the drive belt tensioner for proper operation. Refer to Fan Belt Replacement and Generator and Air Conditioning Compressor and Power Steering Pump Belt Replacement . Did you find and correct the condition? | Go to Step 9 | Go to Step 6 | |||||
Verify that the drive belt is the correct length. Did you find and correct the condition? | Go to Step 9 | Go to Step 7 | |||||
Inspect for misalignment of a pulley. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 | |||||
Inspect for the correct pulley size. Did you find and correct the condition? | Go to Step 9 | Go to Diagnostic Aids | |||||
9 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 | ||||
