Diagnostic Aids
The accessory drive components can have an affect on engine vibration. Such as but not limited to the A/C system over charged, the power steering system restricted or the incorrect fluid, or an extra load on the generator. To help identify an intermittent or an improper condition, vary the loads on the accessory drive components.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This test is to verify that the symptom is present during diagnosing. Other vehicle components may cause a similar symptom such as the exhaust system, or the drivetrain.
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This test is to verify that the drive belt or accessory drive components may be causing the vibration. When removing the drive belt the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belt removed.
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The drive belt may cause a vibration. While the drive belt is removed this is the best time to inspect the condition of the belt.
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Inspecting of the fasteners can eliminate the possibility that a wrong bolt, nut, spacer, or washer was installed.
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This step should only be performed if the water pump is driven by the drive belt. Inspect the water pump shaft for being bent. Also inspect the water pump bearings for smooth operation and excessive play. Compare the water pump with a known good water pump.
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Accessory drive component brackets that are bent, cracked, or loose may put extra strain on that accessory component causing it to vibrate.
Step | Action | Yes | No | ||||
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Notice: Do not use belt dressing on the drive belt. Belt dressing causes the breakdown of the composition of the drive belt. Failure to follow this recommendation will damage the drive belt. DEFINITION: The following items are indications of drive belt vibration:
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1 | Did you review the Drive Belt Symptom operation and perform the necessary inspections? | Go to Step 2 | |||||
Verify that the vibration is engine related. Does the engine make the vibration? | Go to Step 3 | Go to Diagnostic Aids | |||||
Does the engine still make the vibration? | Go to Vibration Analysis - Engine in Vibration Diagnosis and Correction | Go to Step 4 | |||||
Inspect the drive belt for wear, damage, debris build-up and missing drive belt ribs. Did you find any of these conditions? | Go to Step 5 | Go to Step 6 | |||||
5 | Install a new drive belt. Refer to Drive Belt Replacement . Did you complete the replacement? | Go to Step 10 | -- | ||||
Inspect for improper, loose or missing fasteners. Did you find any of these conditions? | Go to Step 7 | Go to Step 8 | |||||
7 |
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Did you complete the repair? | Go to Step 10 | -- | ||||
Inspect for a bent water pump shaft. Refer to Water Pump Replacement in Engine Cooling. Did you find and correct the condition? | Go to Step 10 | Go to Step 9 | |||||
Inspect for bent or cracked brackets. Did you find and correct the condition? | Go to Step 10 | Go to Diagnostic Aids | |||||
10 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 | ||||
