Cummins N14 STC, Celect, Celect Plus – Service Manual Engine Noise Excessive

Lubricating oil pressure is below specification

Check the oil pressure. If the pressure is low, reference the Lubricating Oil Pressure Low troubleshooting symptom tree in Section TS.

Lubricating oil level is below specification

Check the oil level. Verify the dipstick calibration and the oil pan capacity. Fill the system to the specified level. Refer to Procedure 007-009 and Procedure 007-037 in Section 7.

Coolant temperature is above specification

Check the coolant level. Refer to the Coolant Temperature is Above Normal – Sudden Overheat or the Coolant Temperature is Above Normal – Gradual Overheat troubleshooting symptom tree in Section TS.

Lubricating oil is thin or diluted

Check the viscosity of the oil sample. Refer to the Lubricating Oil Contaminated troubleshooting symptom tree in Section TS.

Fan drive belt is loose, tight, or not in alignment

Check the fan drive belt. Refer to Procedure 008-002 in Section 8.

Fan is loose, damaged, or has excessive hub bearing end play

Check the fan. Refer to Procedure 008-040 in Section 8.

Engine mounts are worn, damaged, or not correct

Check the engine mounts. Refer to Procedure 016-010 in Section 16.

Air intake or exhaust piping is contacting the chassis or cab

Inspect the air piping, chassis, and cab for contact points. Refer to the OEM service manual.

Air intake or exhaust leaks

Inspect the air intake and exhaust systems for air leaks. Refer to Procedure 010-024 in Section 10.

Turbocharger noise

Refer to the Engine Noise Excessive – Turbocharger troubleshooting symptom tree in Section TS.

Overhead adjustments are not correct

Measure and adjust the overhead settings. Refer to Procedure 003-004 in Section 3.

Injector(s) are malfunctioning

Perform diagnostics to find the damaged injector(s). Replace the injector(s) as necessary. Refer to Procedure 006-026 in Section 6.

Overhead components are damaged

Inspect the rocker levers, rocker shafts, cam followers or tappets, push rods, and valves for damage or excessive wear. Refer to Procedure 003-009 in Section 3, Procedure 004-001 and Procedure 004-014 in Section 4, and Procedure 002-004 in Section 2.

Accessory drive is worn (axial end play is out of specification)

Check the accessory drive axial end play. Inspect the shaft for wear. Refer to Procedure 009-001 in Section 9.

Static injection timing is not correct

Check the static injection timing. Refer to Procedure 006-025 in Section 6.

Vibration damper is damaged

Inspect the vibration damper. Refer to Procedure 001-052 in Section 1.

Air compressor noise is excessive

Refer to the Engine Noise Excessive – Air Compressor troubleshooting symptom tree in Section TS.

Fan clutch, hydraulic pump, or freon compressor noise is excessive

Isolate each component and check for noise. Refer to the OEM service manual.

Drivetrain noise is excessive

Disconnect the drivetrain. Check for engine noise. Refer to the OEM service manual.

Gear train backlash is excessive or the gear teeth are damaged

Check the gear backlash and the gear teeth. Refer to Procedure 001-013 and Procedure 001-018 in Section 1.

Main bearing or connecting rod bearing noise

Refer to the Engine Noise Excessive – Main Bearing troubleshooting symptom tree in Section TS.

Flywheel or flexplate capscrews are loose or broken

Check the flywheel or flexplate and the mounting capscrews. Refer to Procedure 016-005 in Section 16.

Piston, piston rings, or cylinder liner is worn or damaged

Inspect the air intake system for leaks. Refer to the Engine Noise Excessive – Piston troubleshooting symptom tree in Section TS.

Power take-off (PTO) is damaged

Check the PTO for damage and correct installation. Refer to the OEM service manual.