... exhaust? Hmm.
perhaps the egr is stuck open.
also backpressure from a plugged cat will force exhaust out the intake.
as would a broken intake valve...

you could be misreading blowby as exhaust... it's smokey if the rings are stuck.
take the crankcase vent tube off the valve cover see if the smoke is emanating from there...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!