B5.9G, B5.9LPG, B Gas Plus, B LPG Plus, and B Gas International Engines – Air Compressor Cycles Frequently

Symptom Tree  

Air system leaks

Block the vehicle wheels and check the air system for leaks with spring brakes applied and released. Check for leaks from the air compressor gaskets and the air system hoses, fittings, tanks, and valves. Refer to the OEM service manual.


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 (Air Compressor Carbon Buildup) in Section 7.


Air system component is malfunctioning

Check the operation of check valves, alcohol evaporators, air dryers, and other OEM-installed air system components. Refer to the OEM service manual.


Air dryer outlet check valve is sticking

Lubricate or replace the air dryer outlet check valve assembly. Refer to the OEM service manual.

Contact a Cummins Authorized Repair Facility

Last Modified:  15-Feb-2005