Drive belt whistle
Note: A whistling noise when starting in cold, humid conditions that decreases once the vehicle reaches operating temperature is considered normal.
Diagnostic information
The symptom may be intermittent due to moisture on the drive belts or pulleys. It may be necessary to spray a small amount of water on the drive belt to duplicate the condition and confirm the customer 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 chart.
- The noise may not be engine related. At this point, you want to confirm that the noise is coming from the engine. If the noise is not coming from the engine, you should not continue with this diagnostic procedure.
- This noise can be caused by internal engine components. Removing the drive belt and letting the engine run for a while 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 stripes of rubber in the grooves of the drive belt caused by the accumulation of rubber dust.
- Misalignment of the accessory drive system pulleys may be caused by improper fastening of the accessory drive component (air conditioning compressor, generator, etc.) or pulley. Misalignment may also be caused by improper installation of the pulley 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 pulley is misaligned, refer to the service information for the appropriate component for installation and removal procedures.
- Inspecting the fasteners can eliminate the possibility that the wrong fasteners were installed.
- Inspection of pulleys for bends should include checking for dents or other damage that would prevent the drive belt from seating properly in all pulley grooves or on a smooth surface when the back side of the belt is used as the drive surface.
- Replacing the drive belt, unless it is damaged and there is excessive dust particle build-up, will only be a temporary repair.
Diagnostic table
Note: A whistling noise when starting in cold, humid conditions that decreases once the vehicle reaches operating temperature is considered normal.
Definition: Accessory belt whistle can be described as a high pitched sound heard when the drive belt or pulley is rotating.
| Step | Operation | Values | Yes | No |
| 1 |
Have you reviewed the information provided in the Symptoms section and performed the required checks?
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-
|
Jump to operations 2
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Go to item Symptoms
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| 2 |
Confirm customer complaint. Is there a whistling noise?
|
-
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Jump to operations 3
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See diagnostic recommendations in this section
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| 3 |
Is the whistling sound still present?
|
-
|
The drive system of the units is in order.
Go to "Symptoms" and start the noise diagnostic again
|
Jump to operations 4
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| 4 |
Inspect for severe pilling, which is defined as pilling that exceeds 33% of the belt groove depth.
Is there any pilling in the drive belt grooves?
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-
|
Jump to operations 5
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Jump to operations 6
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| 5 |
Clean the drive belt pulleys with a wire brush.
Are the belt pulleys clean?
|
-
|
Jump to operations 15
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Jump to operations 6
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| 6 |
Inspect the pulleys for misalignment.
Is there any misalignment of the pulleys?
|
-
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Jump to operations 7
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Jump to operations 8
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| 7 |
Replace or repair misaligned pulleys.
Is the renovation complete?
|
-
|
Jump to operations 15
|
-
|
| 8 |
Inspect the drive component mounting brackets for bends or damage.
Are there any bent or damaged brackets?
|
-
|
Jump to operations 9
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Jump to operations 10
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| 9 |
Replace or repair any brackets that are bent or damaged.
Is the renovation completed?
|
-
|
Jump to operations 15
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-
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| 10 |
Inspect for missing, loose or incorrect fasteners.
Are any missing, loose or incorrect fasteners found?
|
-
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Jump to operations 11
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Jump to operations 12
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| 11 |
Tighten all loose fasteners to the specified torque.
Replace all incorrect or missing fasteners.
Is the renovation completed?
|
-
|
Jump to operations 15
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-
|
| 12 |
Inspect the pulley for bends.
Are any pulleys found to be bent?
|
-
|
Jump to operations 13
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Jump to operations 14
|
| 13 |
If necessary, replace bent pulleys.
Is the renovation complete?
|
-
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Jump to operations 15
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-
|
| 14 |
Replace the accessory drive belt, see. Section 1B, Engine Mechanical System - 2.0 Diesel.
Is the renovation complete?
|
-
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Jump to operations 15
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-
|
| 15 |
Reinstall the accessory drive belt and operate the system to confirm completion of the repair.
Is the whistling noise eliminated?
|
-
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The drive system of the units is in order
|
Jump to "Symptoms" and restart the diagnostics
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