- A high-pitched, frequency-specific sound that is heard with each revolution of the accessory drive belt or pulley.
- This sound may occur during cold, humid starting conditions and will subside once the vehicle has warmed up to normal operating temperature.
Diagnostic information
This characteristic noise can be caused by moisture on the belt itself or on the accessory drive pulley. To simulate this problem, a small amount of water can be sprayed on the drive belt to verify the customer complaint. If spraying with water reproduces this symptom, the most likely solution is to clean the accessory drive pulley.
The characteristic whistling noise can also be caused by loose or improperly installed body or suspension components, or other elements on the vehicle.
Description of the test
The numbers below refer to the operations in the diagnostic table:
2. This characteristic noise may not be related to the engine. At this point, you should verify that the noise is coming from the engine. If the noise is not caused by the engine, do not use this chart for further diagnosis.
3. This noise can be caused by internal engine components. Removing the belt and running the engine for a few seconds will help determine whether the whistling noise is related to the drive belt or not. Without the drive belt, the water pump will not work and the engine may overheat. Diagnostic trouble codes (DTCs) may also be activated if the engine is running without the drive belt.
4. Inspect the drive belt for build-up, adhesion, or foreign particle inclusions. These are small balls, build-ups, or veins in the grooves of the drive belt caused by the accumulation of rubber dust.
6. Misalignment of accessory drive pulleys may be caused by improper installation of the pulley or accessory drive components, or the pulley may have been bent during a previous repair. Check the alignment of the pulleys by placing a straight edge in the grooves of two or three pulleys. If a misaligned pulley is found, check the installation and removal procedures for that accessory drive pulley.
10. Inspecting the fasteners will help eliminate the possibility of an improperly installed bolt, nut, gasket or washer.
12. Inspection of the accessory drive pulley shall include inspection for kinks, dents or other damage that would prevent the drive belt from properly engaging the pulley grooves or that would prevent it from contacting a smooth surface when the back side of the drive belt is used to drive the pulley.
14. Replacing the drive belt when it is not damaged or does not have excessive dust particle build-up will only be a temporary repair.
| Step | Operation | Values | Yes | No |
| 1 |
Have you reviewed the diagnostic information Symptoms - Engine Mechanical and performed the necessary inspections?
|
-
|
Jump to operations 2
|
Go to item Symptoms
|
| 2 |
Check for the presence of a whistling sound.
Is the engine making a whistling sound?
|
-
|
Jump to operations 3
|
Go to Diagnostic Information
|
| 3 |
Is the whistling sound still present?
|
-
|
Jump to operations 4
|
|
| 4 |
Inspect the drive belt for sticking and inclusions in an area of at least 1/3 of the drive belt groove depth.
Are there any deposits or inclusions in the drive belt grooves?
|
-
|
Jump to operations 5
|
Jump to operations 6
|
| 5 |
Clean the accessory drive pulley with a wire brush.
Is the accessory drive pulley clean?
|
-
|
Jump to operations 15
|
-
|
| 6 |
Check the alignment of the accessory drive pulley.
Are there any pulleys that are misaligned or offset?
|
-
|
Jump to operations 7
|
Jump to operations 8
|
| 7 |
Replace and/or repair faulty accessory drive pulleys.
Were the problematic accessory drive pulleys repaired and/or replaced?
|
-
|
Jump to operations 15
|
-
|
| 8 |
Inspect the accessory drive bracket for bends or cracks.
Has the accessory drive bracket been inspected for bends and/or cracks?
|
-
|
Jump to operations 9
|
Jump to operations 10
|
| 9 |
Replace accessory drive brackets that are bent and/or cracked.
Have the accessory drive brackets been replaced if cracked and/or bent?
|
-
|
Jump to operations 15
|
-
|
| 10 |
Inspect for proper installation, looseness and/or missing fasteners.
Were any improperly installed, loose and/or missing fasteners found?
|
-
|
Jump to operations 11
|
Jump to operations 12
|
| 11 |
Have the fasteners been replaced and/or tightened?
|
-
|
Jump to operations 15
|
-
|
| 12 |
Check the bends of the auxiliary drive pulleys.
Was a bent accessory drive pulley found?
|
-
|
Jump to operations 13
|
Jump to operations 14
|
| 13 |
Replace the bent accessory drive pulley.
Has the bent accessory drive pulley been replaced?
|
-
|
Jump to operations 15
|
-
|
| 14 |
Replace the drive belt. See. Section 1C1, Engine Mechanical - FAM II 2.4D.
Has the drive belt been replaced?
|
-
|
Jump to operations 15
|
-
|
| 15 |
Is the whistling sound still present?
|
-
|
-
|
The system is normal
|
(Original version of the article on the website «CHEVYMAN»)