Drive belt whine
Note: Whistling when starting in cold wet conditions, which decreases as the vehicle warms up to operating temperature, is normal.
Diagnostic Information
The symptom may be intermittent due to moisture on the drive belts or pulleys. It may be necessary to spray some water on the drive belt to duplicate the condition and confirm the customer's complaint. If spraying water on the drive belt system repeats the symptom, cleaning the belt pulleys may be the solution.
The noise may be caused by a loose or improperly installed body component, suspension component, or other item.
Description of the test
The item numbers below are the step numbers in the diagnostic table.
- The noise may not be engine related. At this stage, confirmation should be obtained that the noise is emitted by the engine. If it is not the engine that is making the noise, do not continue with this diagnostic procedure.
- 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.
- Inspect all drive belt pulleys for pilling.
Note: Pilling is the formation of small balls (growths) or strips of rubber in the grooves of the drive belt caused by the accumulation of rubber dust.
- Misalignment of the accessory drive system pulleys can be caused by improper attachment of the accessory drive component (air conditioning compressor, generator, etc.) or pulley. Skew can also be caused by improper pulley installation 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 a misaligned pulley is detected, refer to the appropriate component service information for installation and removal procedures.
- Inspection of fasteners can eliminate the possibility that the wrong fastener was installed.
- Inspection of pulleys for kinks should include checking for dents or other damage that would prevent proper seating of the drive belt in all pulley grooves or on a smooth surface when the back of the belt is used as a drive surface.
- Replacing the drive belt, if it is not damaged and there are no excessive dust particles, will only be a temporary repair.
Diagnostic table
Note: Whistling when starting in cold wet conditions, which decreases as the vehicle warms up to operating temperature, is normal.
Definition: An accessory drive belt whistle can be described as a high-pitched sound that is heard when the drive belt or pulley rotates.
| 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 whistling noise?
|
-
|
Go to operation 3
|
See diagnostic advice in this section
|
| 3 |
Is the whistling sound still present?
|
-
|
The drive system of the aggregates is in order.
Go to "Symptoms" and restart noise diagnostics
|
Go to operation 4
|
| 4 |
Inspect for severe pilling, i.e. one that exceeds 33% of the belt groove depth.
Is there pilling in the grooves of the drive belt?
|
-
|
Go to operation 5
|
Go to operation 6
|
| 5 |
Clean the drive belt pulleys with a wire brush.
Are the belt pulleys cleaned?
|
-
|
Jump to operation 15
|
Go to operation 6
|
| 6 |
Inspect pulleys for misalignment.
Is there a pulley misalignment?
|
-
|
Jump to Operation 7
|
Jump to operation 8
|
| 7 |
Replace or repair misaligned pulleys.
Repair completed?
|
-
|
Jump to operation 15
|
-
|
| 8 |
Inspect accessory drive component mounting brackets for kinks or damage.
Are brackets found to be bent or damaged?
|
-
|
Go to operation 9
|
Jump to operation 10
|
| 9 |
Replace or repair any brackets that are bent or damaged.
Has the repair been completed?
|
-
|
Jump to operation 15
|
-
|
| 10 |
Inspect for missing, loose, or incorrect fasteners.
Have you found any missing, loose, or incorrect fasteners?
|
-
|
Go to operation 11
|
Go to operation 12
|
| 11 |
Tighten all loose fasteners to the correct torque.
Replace any incorrect or missing fasteners.
Has the repair been completed?
|
-
|
Jump to operation 15
|
-
|
| 12 |
Inspect the pulley for bends.
Are sheaves found with bends?
|
-
|
Jump to operation 13
|
Go to operation 14
|
| 13 |
If necessary, replace the pulleys with bends.
Repair completed?
|
-
|
Jump to operation 15
|
-
|
| 14 |
Replace accessory drive belt, see Section 1B, Engine Mechanical - 2.0 Diesel.
Repair completed?
|
-
|
Jump to operation 15
|
-
|
| 15 |
Reinstall the accessory drive belt and operate the system to confirm repair is complete.
Has the whistling noise been eliminated?
|
-
|
The drive system of the aggregates is in order
|
Go to "Symptoms"and restart diagnostics
|