Yeah, i'd go with reducing the level of oil as well.

As for the stop smoke products, the only time I would use this is if I was trying to flog a car off quickly. Ive used it in an earlier 230E and worked for a very short period (Weeks) and then the smoking came back. Or it may have been a coincidence.

Don't fix the symptoms - fix the problem.

Judging by the syptoms you gave it sounds like valve stem seals leaking or it could just be the overfilled oil.

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1985 190E - Gone
1989 230E - Gone
1995 C200 - Gone
1993 280E 120000KM - Built like a brick, the best one yet