I am stumped. I have a 1996 (5.9) B model Cummins that is blowing oil out of breather pipe when pulling a heavy load at high rpms. Overhauled engine--New turbo for this problem. Still blowing oil. It will blow out 4 quarts in a 50 mile range running at 70-75 miles a hour. f you slow down to 65 mph it won't use any oil. New Pistons and rings for this problem. Have contacted dealers and other mechanics. They haven't a clue.

 

How much oil are we talking here? Most of these trucks put a few drips out the tube during and after a hard pull.

 

Have you tried contacting Cummins? That would be my next step if it were me. Does it seem to push the oil out only at high boost? It kind of sounds to me like there is a seal in the turbo that is leaking air at higher boost and pressurizing the block.
Oh, by the way, WELCOME!!! You should also fill out your sig so we can help you figure it out better.
Tom

 

first thing I would do is check part number on the oil pan and then check with Cummins for how much is will hold and then calibrate your oil dipstick and make sure it is correct.

 

Sounds to me like one or more of the rings cracked on assembly. I fought blowby problems for a long time after a rebuild only to take the motor down and find top and middle rings broken. They are really fragile and prone to breaking. Did you use a ring compressor?

 

This is going to sound a tad silly but your blow by hose may just be too long....happened to someone on another board.

Have a look at the thread: (check out the 18 th post into the thread)


http://dieselram.com/cgi-bin/ultimat...=001160#000007

Also, have you over filled your engine with oil??