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 the loads, making sure the components are operated to maximum capacity. An overcharged A/C system, power steering system with a pinched hose or wrong fluid, or a generator failing are suggested items to inspect.
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 the squeal noise is the drive belt or 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 removed, 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 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 belt 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 misaligned pulley using a straight edge in the pulley grooves across 2 or 3 pulleys. If a misaligned 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. 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 Symptoms - Engine Mechanical 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 | |||||
Verify that the correct length drive belt is being used. 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 | ||||
