Diagnostic Aids
A loose or improper installation of a body component, a suspension component, or other items of the vehicle may cause the squeal noise.
If the noise is intermittent, verify the accessory drive components by varying their loads making sure they are operated to their maximum capacity. Inspect for an overcharged A/C system, power steering system with a pinched hose or wrong fluid, or a failing 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. Remove the drive belt and operate the engine for a brief period. This action will help determine if the noise is from the drive belts, or from an accessory drive component. When removing the drive belt 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 remove test the bearings in the accessory drive components for turning smoothly. Also, test the accessory drive components with the engine operating by varying the load on the components in order 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, proper belt tension may not be achieved to keep the drive belt from slipping, which could cause a squeal noise.
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This test is to verify that the drive belts is not too long, which would prevent the drive belt tensioner from working properly. Also, if an incorrect length drive belt was installed, the belt 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 the accessory drive component pulley, or the pulley bent inward or outward from a previous repair. Test for a misalign pulley using a straight edge in the pulley grooves across 2 or 3 pulleys. If a misalign pulley is found, refer to that accessory drive component for the proper installation procedure for that pulley.
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This test is to verify that the pulleys are the correct diameter or width. Use a known good vehicle in order to compare the pulley sizes.
Step | Action | Yes | No | ||||
|---|---|---|---|---|---|---|---|
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Notice: Refer to Belt Dressing Notice in the Preface section. 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 Drive Belt Tensioner Diagnosis . Did you find and correct the condition? | Go to Step 9 | Go to Step 6 | |||||
Inspect for the correct drive belt length. Refer to Drive Belt Replacement . 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 | ||||
