Diagnostic information
Drive train components such as the air conditioning compressor or alternator can affect engine vibration.
To help localize the component causing the noise, vary the load on each component of the drive units in turn and record the effect on vibration, if any.
Description of the test
The item numbers below are the step numbers in the diagnostic chart.
- Confirms the existence of the symptom during diagnosis. Noise may be caused by other components of the vehicle.
- Confirms that the accessory drive belt is causing the noise. Drive belt noise is often confused with internal engine noise due to the similarity in description. Removing the drive belt and running the engine for a while can confirm or deny that the noise is related to the drive belt.
- The drive belt may be the cause of the vibration. It is much easier to inspect the drive belt when it is removed.
- Inspecting the fasteners can eliminate the possibility that the wrong fasteners were installed.
- This step should only be performed if the coolant pump is belt driven. Inspect the coolant pump for a bent shaft. Also inspect the coolant pump bearings for smooth rotation and excessive play. Compare the coolant pump to a known good pump.
- Bent, cracked, or loose accessory drive component brackets can place additional stress on the accessory components, causing them to vibrate.
Diagnostic table
Definition: Drive belt vibration can be defined as a bouncing, shaking or rattling sound. Drive belt vibration typically manifests itself as:
- vibration depends on the engine speed or
- vibration is sensitive to the load of the drive system of the units.
| 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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-
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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 rumbling noise?
|
-
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Jump to operations 3
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See diagnostic recommendations in this section
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| 3 |
Does the vibration noise persist?
|
-
|
The drive system of the units is in order.
Go to "Symptoms" and start diagnostics again
|
Jump to operations 4
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| 4 |
Inspect the accessory drive belt for damage, wear, dirt buildup, or areas with missing ribs.
Are there any damages, wear, dirt build-up or missing ribs?
|
-
|
Jump to operations 5
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Jump to operations 6
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| 5 |
Install a new accessory drive belt, see. Section 1B, Engine Mechanical System - 2.0 Diesel.
Has the accessory drive belt been replaced?
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-
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Jump to operations 9
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-
|
| 6 |
Inspect for correct installation, looseness, missing or damaged fasteners.
Are any incorrect, loose, missing or damaged fasteners found?
|
-
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Jump to operations 7
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Jump to operations 8
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| 7 |
Tighten all loose fasteners to the correct torque according to specifications.
Replace all incorrect or missing fasteners.
Is the renovation completed?
|
-
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Jump to operations 9
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-
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| 8 |
Inspect the drive component mounting brackets for bends, cracks or damage.
Bent brackets found and repaired?
|
-
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Jump to operations 9
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See diagnostic recommendations in this section
|
| 9 |
If required, reinstall the accessory drive belt and operate the system to confirm completion of the repair.
Is the vibration eliminated?
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-
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The drive system of the units is in order
|
See diagnostic recommendations in this section
|