Oil Leak on 2003 4.4i is puzzling me
 

Add another thread on an oil leak to this forum...

Did some searching for the past few days on here, but nothing is really standing out so I wanted to post up my issue.

My X has a oil leak near the oil filter canister. I had the oil changed last week (by a buddy who used to work at BMW) and the oil pressure sensor replaced (I had heard a rattle on occasion on cold start and once saw the "Low Oil Pressure" warning). He also mentioned that he inspected some valve inside the canister (can't recall the exact terminology) due to my comments on the rattle and warning light.

A few days after the change I noticed quite a bit of oil on the ground on the drivers side. I cleaned the engine bay and areas where oil could have accumulated so I can track the leak. The next day I drove ~12 miles and again noticed traces of oil leaking. I was able to determine it was coming from the top of the oil filter canister. I saw traces of oil around the outside and front edge. My buddy came back over and replaced the o-ring on the filter cap and torqued it to ~25 lb/ft.

I drove it today and again noticed a leak. It's leaking around the edge of the oil cap, as if the cap wasn't tight or the pressure is just to high for it to hold. The cap is already torqued above the recommended 25 nM listed on the cap (I think 25 lb/ft is like 35 nM) so I am afraid to go further.

Does anyone have any thoughts on what I can do next?

Thanks guys!

The cap doesn't need to be torqued to prevent leaks, the o-ring itself is what makes the seal. I'd pull the cap off and inspect inside the top where the o-ring sits to make sure there is no scarring or cracks etc. And also make sure the o-ring is sitting properly in the intended groove as many oil change places misplace the o-ring and cause a leak.

I'll pull it off and inspect it again tomorrow. We replaced the o-ring the other day even though the old one didn't look bad or out of place. I hope it's this simple.

We removed the oil filter and inspected the o-ring, cap, and other items. There were no signs of foreign objects on or around the sealing edge. The cap looked good too so everything checked out.

The issue starts after driving for >15 miles. There is a seep trail right in the front of the canister that begins to show. You can see evidence of oil around the seal by the cap.

What else should I investigate? Am I simply not tightening the cap enough?

The o-ring is the ONLY part that makes the seal, and tightness does not affect it... period.

My question would be is the o-ring all the way against the top edge of the cap, or is it in the groove about 1.4 down from the top. If it is all the way against the top ridge, it is wrong. If it is in the proper groove but still leaks, is it an OEM o-ring, or aftermarket? If cleaned and dried, are there any signs of hairline cracks or scratches where the o-ring sits in the housing?

Everything was done with OEM parts. I didn't see any cracks nor did my buddy when he inspected it today. I'll have him check one more time to ensure we are not missing anything obvious here.

I understand there is a valve inside this canister that keeps the oil in the filter housing from draining down. I believe this is the valve my buddy inspected to see if it was causing my start-up rattle (I'll confirm this tomorrow). Now I don't know squat about how things work inside the canister, but could this valve or anything else in the container cause excess pressure in the canister (i.e. causing the oil canister to fill up too much and create pressure that eventually seeps out? Like it's draining way too slow)?

Like some posting here, I too, have been the victim of the oil pressure leak. My 2000 4.4L has 120k miles on it. The incident started about 3 weeks ago, with just a few drops. I paid no attention. Then it was a few MORE drops. The other day I was looking at a 9" stain. So I tried a new seal gasket and new oil filter. Oil is now streaming through the lid. I tried NO filter; same result.
I disassembled the entire oil filter housing. I took all 3 lines off, wiped everything down. I completely emptied the housing, wiped it most of the way out. At a local parts store, he recommended a 20 cent little seal at the bottom of the threads, but inside the housing. There is a little lip right there, he argued, and I might be able to stop the oil before snaking through the threads. Then I put the old seal on the very top of the cap - where it's supposed to go (nothing visibly wrong with it), then I put the new seal in that crevasse where the seal always wants to squish into. (This was all after reassembly of engine bay, obviously).

The result, after 3 seals: no leak after 5 minutes of running and a test drive. Only time will tell, I guess.

...............The crevasse is where the o-ring is supposed to go! Putting it at the very top of the cap is the most common misconceived placement that results in bad oil leaks. The o-ring on just the top edge will leak horribly every time as any oil pressure will just blow it out. The intended groove that it wants to fall into puts the seal tightly into the smoothed machined lip of the housing where no oil can get past it.

In the words of the mythbusters, "Well there's your problem"

listen to the weasel. He is my "go to guy".
I have a leak on my 02 4.4 leaves oil on the passenger side under the engine. Where should i start looking Weas?

Usually where the upper timing cover meets the valve cover gasket, but the oil pressure sensor, vanos solenoid seals, etc. can all leak too. Usually start from the top down, and the valve cover gaskets shouldn't be changed without doing the timing cover gaskets with them, otherwise you're asking for twice as much work lol.

And damn I've been busy lately! I haven't spent much time on the forum at all!