Diagnostic Aids
A loose or improperly installed body or suspension component or other items on the vehicle may cause the squeal noise.
If the squeal is intermittent, verify that it is not the accessory drive components by varying their loads. Ensure they are operating to their maximum capacity. An overcharged air conditioning (A/C) system, a power steering system restriction, incorrect fluid or a failing generator are suggested items to inspect.
Test Description
The numbers below refer to the steps in the diagnostic table.
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The squeal may not be engine related. This step verifies that the engine is making the noise. If the engine is not making the noise do not proceed further in this table
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The squeal may be an internal engine noise. Remove the drive belt and operate the engine for a few seconds. This step verifies that the squealing noise is related to the drive belt or an accessory drive component. With the drive belt removed, the water pump does not operate and the engine may overheat. Diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt removed.
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This step verifies that an accessory drive component does not have a seized bearing. With the belt removed, test the bearings in the accessory drive component for smooth operation. Test the accessory drive component, with the engine operating, by varying the load on the accessory drive component to verify that the component is operating properly.
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This step verifies that the drive belt tensioner is not operating 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 squealing noise.
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This step verifies that the drive belt is not too long, which would prevent the drive belt tensioner from operating properly. If the incorrect length of drive belt is installed, it may not be routed correctly and may be turning an accessory drive component in the incorrect direction.
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Misalignment of the accessory drive pulley 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 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.
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Inspect the accessory drive pulley to verify that it is the correct diameter or width. Using a known good vehicle, compare the accessory drive pulleys.
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 Symptoms - Engine Mechanical and perform the necessary inspections? | Go to Step 2 | |||||
Verify that there is a squealing noise. Does the engine make the squeal noise? | Go to Step 3 | Go to Diagnostic Aids | |||||
Does the squealing noise still exist? | Go to Engine Noise on Start-Up, but Only Lasting a Few Seconds | Go to Step 4 | |||||
Inspect for a seized accessory drive component bearing or a faulty accessory drive component. Did you find and correct the condition? | Go to Step 9 | Go to Step 5 | |||||
Inspect 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 length drive belt. Did you find and correct the condition? | Go to Step 9 | Go to Step 7 | |||||
Inspect for a misaligned pulley. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 | |||||
Inspect for an incorrect size pulley. Did you find and correct the condition? | Go to Step 9 | -- | |||||
9 |
Does the squealing noise still exist? | -- | System OK | ||||
