Cummins N14 STC, Celect, Celect Plus – Service Manual Air Compressor Noise is Excessive

Symptom Tree  t006

This is symptom tree
Cause Correction

Carbon buildup is excessive in the air discharge line, check valve, or cylinder head

Check for carbon buildup. Replace the air compressor discharge line, if necessary. Refer to Procedure 012-003 in Section 12 or Procedure 010-040 and Procedure 010-049 in Section 10.


Ice buildup in the air system components

For all models, check for ice in low spots of the air discharge line, dryer inlet, and elbow fittings. On Holset® models, also check the Econ valve, if equipped. Refer to the OEM service manual.


Air compressor is sending air pulses into the air tanks

Install a ping tank between the air dryer and the wet tank. Refer tothe OEM service manual.


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.


Splined drive coupling or gear is excessively worn

Check the coupling for wear. Refer to Procedure 012-014 in Section 12.


Pin bore wear is excessive

Check for pin bore wear. Refer to Procedure 012-010 in Section 12.


Air compressor is excessively worn or internally damaged

Replace or rebuild the air compressor. Refer to the OEM service manual.


Air compressor drive gear or engine gear train is worn or damaged

Inspect the drive gears and gear train. Repair as necessary. Refer to Procedure 009-001 in Section 9.

Last Modified:  22-Dec-2011