Before the last oil change, I showed the dealer some engine oil which collected in a gully near the oil filter cap and also some which had sprayed onto the air filter cover. When I got the car back, I was told the oil filter cap's gasket was bad. Cleaned up, I now see the same thing happening again and am wondering if this my 2006 530xiT's oil filter housing gasket. Thoughts?

 

well the cup that holds the oil filter has two o-rings which are changed everytime you change the filter. when you buy the filter, it comes with the o-rings.

 

+1, although on the 525 there is only one 0-ring. If yours is leaking, they either:
1) left off the 0-ring, or didn't install straight
2) installed an extra 0-ring which creates a poor seal
3) left junk along the filter housing threads causing a poor seal.

Surprised that an 0-ring would go bad as they are changed frequently enough that the rubber should not decompose. May have been more of a torque problem. Any of the above is an very simple fix. I haven't purchased an 0-ring separately as they usually come with any new 'good quality' filter. But I can't imagine it would be more that a couple of bucks to pick up a new one from the dealer.

 

A common mistake is not removing the old o-rings and installing the new one over the top. No amount of tightening will prevent a leak!

 

+1 ... replacement filters come with all new o-rings! In my experience the only way they "go bad" is if in the removal or installation process they are cut or pinched when the filter canister cap is reinstalled.

 

I'm no mechanic, but my 530xi was leaking oil that would pool up around the oil filter cap. They replaced a gasket directly in front of the oil filter housing that has a black plastic piece covering over it. Hope this helps, Chris.