Diagnostic Aids
The accessory drive components may have an affect on engine vibration. An overcharged air conditioning (A/C) system, a power steering system restriction, or the incorrect fluid, or an extra load placed on the alternator are suggested items to inspect. To help identify an intermittent or an incorrect condition, vary the loads on the accessory drive components.
Test Description
The numbers below refer to the steps in the diagnostic table.
-
This test is to verify that the vibration is present during diagnosing. Other vehicle components may cause a similar symptom such as the exhaust system or the drivetrain.
-
This test is to verify that the drive belts or accessory drive components may be causing the vibration. Remove the drive belts and operate the engine for a few seconds, this will verify if the vibration is related to the drive belts or not. With the drive belts removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belts removed.
-
The drive belts may cause a vibration. While the drive belts are removed this is the best time to inspect the condition of the drive belts.
-
Inspection of the fasteners can address the possibility that a incorrect bolt, nut, spacer, or washer was installed.
-
Inspect the water pump drive shaft for being bent. Also inspect the water pump bearings for smooth operation and above acceptable play. Compare the water pump with a known, good water pump.
-
Accessory drive component brackets that are bent, cracked, or loose may put an extra strain on that accessory component causing it to vibrate.
Step | Action | Yes | No | ||||
|---|---|---|---|---|---|---|---|
|
Notice: Refer to Belt Dressing Notice in the Preface section. DEFINITION: The following items are indications of drive belt vibration:
| |||||||
1 | Did you review the Symptoms - Engine Mechanical diagnostic information, and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Engine Mechanical . | ||||
2 | Verify that the vibration is engine related. Does the engine make the vibration? | Go to Step 3 | Go to Diagnostic Aids | ||||
3 |
Does the engine still make the vibration? | Go to Step 4 | |||||
4 | Inspect the drive belts for wear, damage, debris build-up and missing drive belt ribs. Refer to Drive Belt Replacement - Accessory or Air Conditioning Compressor Belt Replacement . Were any of these conditions found? | Go to Step 5 | Go to Step 6 | ||||
5 | Install new drive belts. Refer to Drive Belt Replacement - Accessory or Air Conditioning Compressor Belt Replacement . Did you complete the replacement? | Go to Step 11 | -- | ||||
6 | Inspect for incorrect, loose or missing fasteners. Were any of these conditions found? | Go to Step 7 | Go to Step 8 | ||||
7 |
Were the fasteners replaced and/or tightened? | Go to Step 11 | -- | ||||
8 | Inspect for a bent water pump drive shaft. Refer to Water Pump Cleaning and Inspection . Did you find and correct the condition? | Go to Step 11 | Go to Step 9 | ||||
9 | Inspect for a bent or cracked accessory drive brackets. Did you find and correct the condition? | Go to Step 10 | -- | ||||
10 | Replace the bent and/or cracked accessory drive brackets. Refer to Compressor Mounting Bracket Replacement . Refer to Generator Bracket Replacement . Was the bent and/or cracked accessory drive brackets replaced? | Go to Step 11 | -- | ||||
11 |
Does the vibration still exist? | -- | System OK | ||||
