M11 Series Engines – Air Compressor Noise is Excessive

Symptom Tree  t006

This is symptom tree t006
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. Check the turbocharger for oil leaks. Check the intake tube for oil. Refer to Procedures 012-003, 010-040 and 010-049.


Air compressor is sending air pulses into the air tanks

Install a ping tank between the air dryer and the wet tank. Refer to the manufacturer’s instructions.


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 the M11 Shop Manual, Bulletin 3666075, and Procedure 009-001.


Air compressor is excessively worn or internally damaged

Replace or rebuild the air compressor. Refer to the manufacturer’s instructions and Procedure 012-014.


Air compressor timing is not correct

Check the air compressor timing. Refer to Procedure 012-014.


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

Inspect the drive gears and gear train and repair as necessary. Refer to Procedures 001-036, 001-039, and 001-040.


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 Master Repair Manual, Holset® Air Compressors, Bulletin 3666121.


Pin bore wear is excessive

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

Last Modified:  30-Jan-2004