- Loud squealing sound that occurs when the drive belt slips (extremely rare on multi-ribbed drive belts)
- Drive belt squealing usually occurs when the belt is heavily loaded, such as when the A/C compressor clutch engages, throttle slips, slips on a stuck pulley, or an accessory drive component is defective.
Diagnostic Information
The characteristic squealing noise can also be caused by a loose or improperly installed body or suspension part, or other components on the vehicle.
If the squealing is intermittent, then it is necessary to check whether this is due to changes in the load on the component (s) drive auxiliary units, to ensure their operation at maximum power. It is recommended to pay attention to the following - excessive freon charge in the air conditioning system, sticking in the power steering system or filling the system with the wrong fluid, generator failure.
Description of the test
The numbers below refer to the operations in the diagnostic table:
2. This screeching sound may not be engine related. At this stage, you should make sure that the engine makes noise. If the noise is not caused by the motor, do not use this chart for further diagnosis.
3. This squealing sound may be caused by internal engine components. Remove the drive belt and run the engine for a few seconds to determine if the squealing sound is related to the drive belt or any accessory drive component. Without a drive belt, the water pump will not work and the engine may overheat. Diagnostic Trouble Codes may also be activated (DTC), if the engine is running without a drive belt.
4. This test checks to see if the bearing of any of the accessory drive components is sticking. With the belt removed, check all bearings of the accessory drive components for smooth rotation. Also test the accessory drive components with the engine running, varying the load on the accessory drive components to verify proper operation.
5. This test is carried out to check the correct operation of the drive belt tensioner. If the drive belt tensioner is not working properly, it will not be possible to maintain proper tension on the belt to prevent slippage, which may cause a squealing sound.
6. This test checks to see if the drive belt is too long, which could prevent the drive belt tensioner from working properly. An installed drive belt of the wrong length cannot be properly routed through the pulleys and the accessory drive component may rotate in the wrong direction.
7. Misalignment of the accessory drive pulleys may be caused by incorrect installation of the accessory drive pulley itself or the accessory drive component, or the pulley may have been bent during a previous repair. Check the alignment of the pulleys on the plane by applying a ruler to the grooves of two or three pulleys. If an offset pulley is found, verify that the mounting and dismounting procedures for that accessory drive pulley match.
8. Inspect pulley (s) drive accessories and make sure they are the correct diameter or width. Compare the accessory drive pulleys with those on a known good vehicle.
| Step | Operation | Values | Yes | No |
| 1 |
Have you read the diagnostic information Symptom - Engine Mechanical and performed the necessary inspections?
|
-
|
Go to operation 2
|
Go to item Symptoms - Engine Mechanical
|
| 2 |
Check for a screeching sound.
Does the engine make a squealing sound?
|
-
|
Go to operation 3
|
Go to Diagnostic Information
|
| 3 |
Is the whistling sound still present?
|
-
|
Go to operation 4
|
|
| 4 |
Check accessory drive bearings for free rotation or accessory components for damage.
Fault found and corrected?
|
-
|
Go to operation 9
|
Go to operation 5
|
| 5 |
Inspect the drive belt tensioner to check for proper operation. Refer to Drive Belt Tensioner Diagnosis.
Fault found and corrected?
|
-
|
Go to operation 9
|
Go to operation 6
|
| 6 |
Check if the drive belt is the correct length.
Fault found and corrected?
|
-
|
Go to operation 9
|
Jump to Operation 7
|
| 7 |
Check pulley alignment.
Fault found and corrected?
|
-
|
Go to operation 9
|
Jump to operation 8
|
| 8 |
Check the correct size of the pulleys.
Fault found and corrected?
|
-
|
Go to operation 9
|
-
|
| 9 |
Is the screeching sound still there?
|
-
|
-
|
System OK
|