SEAL 6D7128 - Caterpillar

Probable Causes
Note: For additional information about engine vibration, refer to Special Instruction, SEHS7914, "Troubleshooting Engine Vibration In Vehicular Equipment".
Loose vibration damper or loose pulley
Faulty vibration damper or faulty pulley
Loose engine supports or faulty engine supports
Engine misfiring
Unbalanced fan blade
Problem with engine driven components
Improper unit injector synchronizationRecommended Repairs
Loose Vibration Damper or Loose Pulley
Inspect the vibration damper for damage. Inspect the pulley for damage. Tighten the bolts and tighten the nuts, if necessary. Refer to Specifications for the proper torque.Faulty Vibration Damper or Faulty Pulley
Install a new vibration damper, if necessary. Install a new pulley, if necessary. Tighten all bolts to the proper torque. Refer to Specifications for the proper torque.Loose Engine Supports or Faulty Engine Supports
Tighten all mounting bolts. Install new components, if necessary.Engine Misfiring
If the engine is misfiring, refer to Troubleshooting, "Engine Misfires, Runs Rough Or Is Unstable".Unbalanced Fan Blade
Loosen the fan drive belts or remove the fan drive belts. Operate the engine for a short time at the rpm that caused the vibration. If vibration is not present, replace the fan assembly.Problem With Driven Components
Check engine driven components for proper alignment. Check engine driven components for balance. Remove the drive belt to a component. Operate the engine for a short time at the rpm that caused the vibration. If vibration is not present, the component is unbalanced. Repair the component or replace the component.Improper Unit Injector Synchronization
Check for proper unit injector synchronization. Perform any necessary adjustments. Refer to Systems Operation, Testing And Adjusting.