Drive Belt Squeal

Drive Belt Squeal Diagnosis

Diagnostic Aids
A loose or improper installation of a 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, making sure they are operating to their maximum capacity. An overcharged air conditioning (A/C) system, a power steering system restriction or the incorrect fluid, or a failing generator are suggested items to inspect.

Test Description





The numbers below refer to the step numbers on the diagnostic table.
2. The squeal 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 in this table
3. The squeal may be an internal engine noise. Remove the drive belts and operate the engine for a few seconds. This will verify if the squealing noise is related to the drive belts or an accessory drive component. With the drive belts removed, the water pump will not operate and the engine may overheat. Also DTCs may set when the engine is operated with the drive belts removed.
4. This test is to verify that accessory drive components do not have a seized bearing. With the belts removed, test the bearings in the accessory drive components for smooth operation. Also test the accessory drive components with the engine operating by varying the load on the accessory drive components to verify that the components are operating properly.
5. This test is to verify that the drive belt tensioners are not operating properly. If the drive belt tensioners are not operating properly, proper belt tension may not be achieved to keep the drive belts from slipping which could cause a squealing noise.
6. This test is to verify that the drive belts are not too long, which would prevent the drive belt tensioners from operating properly. Also if the incorrect length drive belts were installed, they may not be routed correctly and may be turning an accessory drive component in the incorrect direction.
7. Misalignment of the accessory drive pulleys 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 2 or 3 pulleys. If a misaligned pulley is found, refer to that accessory drive component for the proper removal and installation procedure for that pulley.
8. Inspect the accessory drive pulleys to verify that they are the correct diameter or width. Using a known good vehicle, compare the accessory drive pulleys.