Symptom Tree t047
Cause | Correction |
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When troubleshooting engine noise complaints, make sure the engine accessories (air compressor, fan clutch, refrigerant compressor, or hydraulic pump) are not the cause of the noise. Refer to Engine Noise Diagnostic Procedures – General Information at the end of Section TS before using this symptom tree.
Interview the operator to verify the complaint |
Refer to Driveability-General Information, the Driveability/Low-Power Customer Complaint Form, and the Driveability Checklist at the end of Section TS. Follow the instructions on the forms before continuing with this tree. |
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Electronic fault codes active or high counts of inactive fault codes |
Refer to Section TF in the Fault Code Troubleshooting Manual, Bulletin |
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Lubricating oil level is below specification |
Check the oil level. Refer to Procedure 007-009 and |
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Fan clutch, hydraulic pump, or refrigerant compressor noise is excessive |
Isolate each component and check for noise. Refer to the OEM service manual. |
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Fan is loose, damaged, or not balanced |
Check the fan. Refer to |
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Air intake or exhaust piping is contacting the chassis or cab |
Inspect the air piping, chassis, and cab for contact points. Refer to Procedure 010-031 and Procedure 010-080 in Section 10. |
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Engine mounts are worn, damaged, loose, or not correct |
Verify the condition of the mounts. Refer to Procedure 016-010 in Section 16. |
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Air intake or exhaust leaks |
Check for loose or damaged piping connections and missing pipe plugs. Check the turbocharger and exhaust manifold mounting. Refer to |
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Turbocharger noise |
Refer to the Engine Noise Excessive – Turbocharger symptom tree. |
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Vibration damper has failed |
Remove the vibration damper and operate the engine at the rpm where the noise normally occurs. If the noise is still present, proceed to the next step. If the noise is eliminated, replace the vibration damper. Refer to |
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Drivetrain noise is excessive |
Disconnect the drivetrain. Check for engine noise. Refer to the OEM service manual. |
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Air compressor noise is excessive |
Refer to the Air Compressor Noise Is Excessive symptom tree. |
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Overhead adjustments are not correct |
Measure and adjust the overhead settings. Refer to |
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Overhead components are damaged |
Inspect the rocker levers, rocker shafts, and valves for damage or excessive wear. Refer to |
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Injector(s) are malfunctioning |
Perform diagnostics to find the damaged injector(s). Replace the injector(s) as necessary. Refer to |
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Flywheel is loose or damaged |
Check the flywheel. Refer to |
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Gear train backlash is excessive or the gear teeth are damaged |
Check the gear backlash and the gear teeth for excessive wear. |
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Main bearing or connecting rod bearing noise |
Refer to the Engine Noise Excessive – Main Bearing or Engine Noise Excessive – Connecting Rod symptom trees. |
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Piston, piston rings, or cylinder liner is worn or damaged |
Refer to the Engine Noise Excessive – Piston symptom tree. |
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Rear engine power take-off (REPTO) noise is excessive |
Disassemble and repair the REPTO as necessary. Refer to Procedure 009-022 in Section 9. |
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Combustion knocks |
Refer to Engine Noise Excessive – Combustion Knocks symptom tree. |
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Internal engine damage |
Analyze the oil and inspect the filters to locate an area of probable damage. Refer to Procedure 007-013 and |
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