Diagnostic Information
The drive belts themselves do not cause a howling noise. If the noise is intermittent, test the accessory drive components by varying their loads to confirm that they are operating at peak performance. Too much refrigerant in the A/C system, an obstruction in the power steering circuit, or a bad alternator are all likely to be the cause of accessory drive belt whine.
Description of the test
The item numbers below are the step numbers in the diagnostic table.
- This noise may be caused by internal engine components. If you remove the drive belt and let the engine run for a bit, you can confirm or deny that the noise is related to the drive belt.
- Bearing inspection should cover the following drive components:
- drive belt tensioners;
- tension rollers of driving belts;
- generator;
- power steering pump;
- air conditioning compressor.
To determine the location of a failed bearing, it may be necessary to install a drive belt and operate the accessory drive components individually, varying the loads; refer to the relevant sections for component inspection and repair procedures.
Diagnostic table
Definition: Accessory drive belt whine can be defined as a high-pitched, continuous sound that is most likely caused by a failed bearing on one of the accessory drive components.
| Step | Operation | Values | Yes | No |
| 1 |
Have you reviewed the information in the section "Symptoms", and performed the required checks?
|
-
|
Go to operation 2
|
Go to item Symptoms
|
| 2 |
Acknowledge the customer's complaint. Is there a howling noise?
|
-
|
Go to operation 3
|
See diagnostic advice in this section
|
| 3 |
Is the whining sound still there?
|
-
|
The drive system of the aggregates is in order.
Go to "Symptoms" and restart diagnostics
|
Go to operation 4
|
| 4 |
Inspect the accessory drive components for damage, seized bearings, and general problems.
Have damage/seized bearings and general faults in the accessory drive system been found and repaired?
|
-
|
Go to operation 5
|
See diagnostic advice in this section
|
| 5 |
Reinstall the accessory drive belt and operate the system to confirm repair is complete.
Has the howling noise been eliminated?
|
-
|
The drive system of the aggregates is in order
|
Go to "Symptoms"and restart diagnostics
|