Heavy oil leak at site of oil filter lines/filter housing

[DaveInLA]

My 1989 325is has been leaking heavily for a couple weeks now. I've been using Mobil 1 15w-50 in it for about 3-4 years now with NO leaks or irregular consumption at all, until late September, only a couple days before I went away on vacation for a couple weeks. On inspection, the leak is where where the two oil cooler lines join the oil filter housing. Here's a diagram:

http://www.realoem.com/bmw/showparts.do?model=1113&mospid=47309&btnr=17_0061&hg=17&fg=05&hl=12

If I haven't been clear, it's leaking from where the #4 is. I want to just replace the seal/o-ring, but I'm wondering why BOTH lines will be leaking at the same time. What are the chances that both seals broke at the same time, or both lines came loose simultaneously?

This is a heavy leak. When the car is off, it leaks minimally. When the engine is running (driving or idling), it leaks about 2 drops/second-- way too much to drive around in, IMO. I just came back from vacation yesterday night, and I want to fix this. I don't need to do it NOW, as I have another car to drive, but I want to take care of it soon. Thanks

[jlevie]

Have you checked to see if the nuts have loosened? That's been known to happen.

The odds of both seals failing simultaneously or both nuts loosing at the same time is pretty slim, but one could have been seeping for a while before you spotted the leak...

[DaveInLA]

Okay, I just took a look at the car again and I now see that it wasn't leaking from the oil cooling lines, but rather from the bolt that's adjacent the cooler fittings. In the Bentley, on page 4-64 (fig 7-9), it's the hat-shaped bolt that is literally next to the arrow pointing to the left cooler line fitting. I think it's number 6 in this diagram, labeled "hollow bolt":

http://www.realoem.com/bmw/showparts.do?model=1113&mospid=47309&btnr=11_0459&hg=11&fg=30&hl=36

Obviously, I'm not able to see the o-ring or gasket ring from outside the bolt, but when I rub a clean cloth around the underside of the bolt, there's a small amount of moderately fresh oil that wipes off. At this point, do I buy both #5 and #4 in that picture? Should I just unscrew the bolt and replace the o-ring and gasket, or should I do something else first? Any precautions I need to take first?

Anyway, it doesn't leak nearly as much as it did 2 weeks ago, even after a 15 minute drive. Could the old oil (2 weeks stagnant) have crudded up the leak a little?

[Dave]

Have you ruled this out as a cause???

http://e30.bmwdiy.info/oil-leak/index.html

[DaveInLA]

Yes, I have. When it was leaking heavily, I could see the oil gushing out.
--------
Anyway, my concern is that if I remove/loosen the "hollow bolt" that's leaking, the entire oil filter housing will come off and then it'll be a lot more work than I expected. Am I able to replace the o-ring and or gasket to that bolt without moving the filter housing?

[NLCarrII]

Have you ruled this out as a cause???

http://e30.bmwdiy.info/oil-leak/index.html

I agree with Dave. I found this on my car after an oil change. The part is cheap but the entire oil filter housing has to be removed because the control valve is spring loaded. 2-4 hours labor.

Nathan

[DaveInLA]

I suppose it's a possibility, but I really do remember seeing oil ooze out of where the hollow bolt (again, in the diagram) is located.

I just need to know if I can remove that bolt and change the o-ring and seal without having the oil filter housing come out with it. That would create a lot more work.

[jlevie]

The entire housing will come off when you remove the bolt. My advice would be that you head to your dealer and pick up the o-rings for the cooler lines, the large o-ring for the adapter, and the o-ring and crush washer for the bolt. Then remove the adapter and renew all the seals.

[DaveInLA]

The entire housing will come off when you remove the bolt. My advice would be that you head to your dealer and pick up the o-rings for the cooler lines, the large o-ring for the adapter, and the o-ring and crush washer for the bolt. Then remove the adapter and renew all the seals.

Basically, remove the oil filter housing and re-install it after replacing all the gaskets and seals, right?

I think I should be able to do that, but how much other stuff would I have to take off or remove before I do that? For example, based on the way things are installed, I think I should be able to leave the oil cooler and the cooler lines in place (but just detach them from the housing), but would I have to detach any hoses or other lines before doing finishing the job? From this diagram, it really does look pretty straight forward.

http://www.realoem.com/bmw/showparts.do?model=1113&mospid=47309&btnr=11_0459&hg=11&fg=30&hl=36