Glad you asked the question.. mine is doing the same thing. I get oil around the cap but not enough to affect the level on the dipstick. I was wondering what was causing it and the only factor I deduced was the cap.. but was afraid it might be some bigger problem. hope changing to a new cap will solve the problem.. I haven't replaced mine yet, but will soon. Thanks guys.

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Nello Tare

1982 300D (266,001 mi.) looking and running great

Previously owned:
1976 450 SLC
1983 300D
1976 300D
also
1982 Jaguar XJ6 (loved, but gone)