Common Oil Leak Sources

[93 525 Paul]

Didn't find anything on this with a search. Saw a couple things about replacing the oil pan gasket. Also remember reading about the low oil level sensor possibly being a leak source.
The wife's 525 is leaking oil and a general inspection doesn't seem to pinpoint a source. What are the usual sources? How have you located the source? I've not used the UV dye thing and I (surprise)don't have a black light on hand...

[DaveVoorhis]

The valve cover gaskets are a good candidate.

[93 525 Paul]

Does anyone else have bad (and worsening) oil leaks? Seems like the front and rear crank seals are leaking and it's getting pretty bad. Anyone solve the problem?

[Scott C]

Mine was a head gasket...

Scott

[Mendozart]

The oil filter housing is a likely suspect. I did a search and found some good tips on how to DIY. I figured I would do this while I had my cylinder head out.