Air compressor knock

[Waterloo]

(07-23-2017 )Platinumpete Wrote:  2014 pete cm 2350 350k on engine. Knock coming from drivers side front of engine sounds like compressor. Pretty loud till engine warms up then gets quieter. Had front pulleys checked and overhead run to eleminate those issues. Any ideas?

Rawze pointed to the fuel pump... You do know about the fuel pumps on your particular motor blowing apart and essentially creating a boat anchor under your hood? Eats the crank shaft and all of that stuff? Pull the oil and fuel filters and check for metal, carve those suckers apart. If the filters are clean, no metal, it may be soot build up in your air compressor head. I don't know if your particular air compressor is like the one on my CM-871, if it is, there should be a head rebuild kit for it. The air compressors on the cummins are about the only good engineering they have going for them. New air compressor head and gasket kit runs around $500 and normally solves the knock. Pray it is the air compressor. ;-)