My 1990 300SE doesn't have the original engine but an earlier version of the M103. When they installed the rebuild transmission in April they also replaced the rear engine main seal, that's leaking now. What I suspect has happened is that they installed a rear main seal for the later version of the M103 that was originally in the car. I looked at the part numbers and they are different, can they be interchanged and could this be the reason for the leak?

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

make sure the oil is not coming from up above because head gasket leaks are not unusual on those engines

I replaced the head gasket a year and half ago, that's when we found out it wasn't the original engine.

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

when they installed the new seal its possible that the spring that sits inside the seal came off and just sits on the crank.


Seen it a few times.

Would that create a sound? I'm asking because at the same time it started to leak a weird sound appeared.

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).