I have a 97 m11 cummins. I checked the motor a month ago and truck had no blow bye at all. Today I was walking by truck and noticed an oil smell, it was the blow bye line. So i took the oil cap off and it also had some blow bye, nothing horrible but still had blow bye. Wondering what would cause this so sudden and what i should do. Someone said it could be the aircompressor going bad and causing the oil pump to act up. Any suggestions. Thanks.
Things it could be: Air Compressor and Rings are big ones. To check if it is the rings, with the engine COLD, put your hand down through the oil fill cap and try to feel for the oil pulsating with the engine. The Air Compressor is a normal problem for the M11's.
Is your oil level rising? Reason i ask is we had the same problem on our 2002 M11. Turned out to be fuel getting into the oil and causing a massive amount of blow by, at least i assume. Our problem was low oil pressure but the blow by stopped also with the fixing of the problem The problem was a bad (i cant remember the name of the part) fuel something or another box that mounted to the side of the engine block on the driver side...... It was $900 from Kenworth. I replaced that and no more blow by.