Oil leak from filter housing (expanding O-ring)
 

Hi everyone,

I just did oil change on my 99 SLK 230 yesterday and used a new filter kit from the dealer. After I was done, I started the engine and it all seemed ok. After running the engine for about a minute, I noticed oil leak from the O-ring. Turned the car off and dried the area. The O-ring had a bulge at the area where the oil appeared. I removed the cap and made sure all is in the right place. The O-ring seemed as good as new. Replaced and tightened the cap a little bit more that a hand-tight. Inspected the O-ring and made sure there are no bulges. Started the engine again. No leaks for about a minute, but as soon as started warming up it started tearing up (see pics).

It almost seems like it is building pressure and pushing the O-ring outward.

The only thing I can think of is that at the time I replaced the filter, the housing looked really dirty, so I used a long screwdriver and a rug to clean it up. I noticed two valves/sensor looking things at the bottom of the oil filter housing. I hope I did not damage any of them...

What are those two things and how can I test they are still functioning? Any idea why it is building pressure from the inside?

Thanks,

Rick

Hmm.. another forum ;) It cannot be stiing in its seat properly or it has stretched.

Bazzle

Hi Bazzle,

I did try 2 more times today, new O-ring and tightening the cap more - no luck. It always pops out on one of the sides and it creates a bulge, even when I apply more pressure on the cap... seems awfully allot of pressure from the inside...

How can I remove or replace the valves at the bottom of the filter housing?

I tried hand-tight and that didn't work as well, in fact it starts leaking almost right away and at a faster paste. I guess when the cap is less tight, the O-ring gives in at a lower pressure.

Old O-ring is in the trash. I have done a few oil changes in my life before, I'm not a virgin when it comes to working on Mercedes, I owned 17 different ones over the last 14 years.

The issue here is something more serious:

If anyone can provide me more information on the valves at the bottom of the oil filter housing, it would be greatly appreciated...

Is it possible to remove or replace them? How do I test them and/or clean them up? ALOT of sludge and small black particles were removed when I used the screwdriver to clean, I still think they are COMPLETELY BLOCKED...

bazzle, do you have any info on that???

Thanks

Screwdriver prob not a good idea.
from your photo the O ring should be down into the body after screwing on. I think you have rolled it on too high. See pic below of another installation.

Bazzle