Thought I'd post this here in case someone else runs into this issue- Fired up our D3G the other day, and noticed a fair cloud of smoke from the stack at throttle up; white smoke, but smelling very much like engine oil rather than diesel. Pulled the access panels to look at the engine, and found oil dripping out of the pipe/muffler joint and dripping onto the exhaust manifold among other things. Blown turbo, I thought, and pulled the intake boot to inspect the compressor wheel. No shaft play, and the bearing feels fine. As I was preparing to pull the turbo off, I started researching possible alternate reasons for oil in the muffler- found a suggestion that the oil drain line from the turbo might be obstructed, causing oil to be forced through the seal into the turbine housing. No such luck. What I did find is shown below. It's the breather hose that comes down from the valve cover, and it's pretty well plugged into the (currently frozen) mud in the bottom of the engine bay. Someone took our dozer for a swim, and this is the result. Anyhow, the breather being unable to breathe increased crankcase pressure sufficiently to push oil into the turbo and up into the muffler. I cleaned the mud out of the breather hose, and the smoking stopped within a few minutes. So at least I don't have to replace the turbo, but I do get to clean out the bottom of the engine bay.
That looks like a job, get it before it dries I suppose. Another confusing one is when condensation freezes up inside of the tube and oil starts leaking from everywhere else. I think that only happens on gas engines though.
Thanks for the post. I am going to check the pan on my 931 to insure it is not built up with twigs and crap. Little older but might be the same.
I think you'd have to have a lot of mud in a 931 to reach the breather but it does add up over time.