For 1990-2009 cars

## Drive Belt Chirping, Squeal, and Whine Diagnosis Whine

### Diagnostic Aids

The drive belts will not cause the whine noise.

If the whine noise is intermittent, verify the accessory drive components by varying their loads making sure they are operated to their maximum capacity. Such items, but not limited to, may be an A/C system overcharged, the power steering system restricted or the wrong fluid, or the alternator failing.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This test is to verify that the noise is being caused by the drive belts or the accessory drive components. When removing the drive belt, the water pump will not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belts removed.

2. The inspection should include checking the drive belt tensioners and the drive belt idler pulley bearings. The drive belts may have to be installed and the accessory drive components operated separately by varying their loads. Refer to the suspected accessory drive component for the correct inspection and replacement procedure.

Step | Action | Yes | No
--- | --- | --- | ---
Notice: Refer to Belt Dressing Notice in the Preface section. DEFINITION: A high pitched continuous noise that may be caused by an accessory drive component failed bearing.
1 | Did you review the Symptoms - Engine Mechanical diagnostic information, and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Engine Mechanical
2 | Verify that there is a whine noise. Does the engine make the whine noise? | Go to Step 3 | Go to Diagnostic Aids
3 |

Important: When removing the drive belt the water pump will not be operating and the engine may overheat.

1. Remove the drive belt. Refer to Drive Belt Replacement.
2. Operate the engine for no longer than 30 to 40 seconds.

Does the whine noise still exist?

Go to Symptoms - Engine Mechanical

Go to Step 4

4 | Inspect for a failed accessory drive component bearing. Did you find and repair the condition? | Go to Step 5 | Go to Diagnostic Aids
5 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | --

## Drive Belt Chirping, Squeal, and Whine Diagnosis Squeal

### Diagnostic Aids

A loose or incorrect 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. An overcharged A/C system, power steering system with a pinched hose or wrong fluid, or a alternator failing are suggested items to inspect.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 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.

2. 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 will not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belt removed.

3. 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 correctly.

4. This test is to verify that the drive belt tensioner operates correctly. If the drive belt tensioner is not operating correctly, correct belt tension may not be achieved to keep the drive belt from slipping which may cause a squeal noise.

5. This test is to verify that the drive belt is not too long, which may prevent the drive belt tensioner from working correctly. Also if an incorrect length drive belt was installed, it may not be routed correctly and may be turning an accessory drive component in the wrong direction.

6. Misalignment of the pulleys may be caused from incorrect 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 correct installation procedure for that pulley.

7. 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
--- | --- | --- | ---
Notice: Refer to Belt Dressing Notice in the Preface section. DEFINITION: The following items are indications of drive belt squeal:

• | A loud screeching noise that is caused by a slipping drive belt. This is unusual for a drive belt with multiple ribs.

• | The noise occurs when a heavy load is applied to the drive belt, such as an air conditioning compressor engagement snapping the throttle, or slipping on a seized pulley or a faulty accessory drive component.

1 | Did you review the Symptoms - Engine Mechanical diagnostic information, and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Engine Mechanical
2 | Verify that there is a squeal noise. Does the engine make the squeal noise? | Go to Step 3 | Go to Diagnostic Aids
3 |

Important: When removing the drive belt the water pump will not be operating and the engine may overheat.

1. Remove the drive belt. Refer to Drive Belt Replacement.
2. Operate the engine for no longer than 30 to 40 seconds.

Does the noise still exist?

Go to Symptoms - Engine Mechanical

Go to Step 4

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
5 | Test the drive belt tensioner for correct operation. Refer to Drive Belt Tensioner Diagnosis. Did you find and correct the condition? | Go to Step 9 | Go to Step 6
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
7 | Inspect for misalignment of a pulley. Did you find and correct the condition? | Go to Step 9 | Go to Step 8
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