Losing Oil while driving
 

While driving at highway speeds for a while, my non-turbo 300TD wagon leaks enough oil to burn off a fair amount on the tailpipe, causing a plume of smoke behind the car.

Parked, doesn't leak a thing, other than the leftovers that drips off the crossmember and transmission from the drive.

Degreased the engine, and there's no obvious leaks, so it's hard to tell where the heck its coming from. Has anyone had this issue? I'm guessing it's a seal that gives to the higher oil pressure of a highway drive, but after that, dunno... Thanks for reading-

Clean it off and hold the engine at 3000rpm after it gets hot. Oil pressure is not dependent on engine load so if it is leaking on the highway it should leak there.