[TMcNasty]

So I have the weepy oil cap syndrome. I'd like to order a new one. Who's got the best deal? Part number?

Shockingly can't find the part number using search.

P.S. I know about the M3 cap, but do not want!

 

[russap5]

$11 at Tischer. #11127509328

I haven't tried this part but you may want to order a new gasket and see if it works on your current oil cap and seals up any leaks.
gasket - #11127837024 http://www.realoem.com/bmw/showparts.do?model=BL93&mospid=47714&btnr=11_2995&hg=11&fg=15

 

[OC e39r]

Here you go..
RealOEM.com BMW E39 M5 Cylinder head cover

 

[AmpliFyre]

try bending the metal up into the cap? should give a tigher seal