I have a friend who owns a 1993 300SD with the OM603.971 motor and he is trying to figure out an unusual problem. When the engine is started up after the vehicle has been sitting unused for several days it smokes. If the 300SD is driven everyday it doesn't smoke on startup. I initially suspected that it might be bad valve stem seals, but the head has new valve stem seals along with a new head gasket. The 300SD has about 130K miles on it I believe. He is also pretty certain that the smoke it produces on startup is caused by oil, as opposed to being diesel smoke. Does anyone have any ideas on what might be causing this problem?

Thanks in advance.

-Steve

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1987 300TDT smoke silver w/ burgundy leather interior
2000 VW Passat wagon indigo blue w/ beige leather interior
1985 Mustang SVO
1970 Chevrolet K10 fleetside, shortbed