E39 Oil Leak Troubleshoot

[kenskornerstone]

Got an oil leak that's showing up in 2 places on my '99 528ia m52tu. 1) Right lower corner of the oil pan which drips on to the lower power sterring hoses. It's not the power sterring hoses as I check this out (and replaced not to long ago). Oil pan gasket shows no swelling but just a drip off the right corner (tab). 2) Another leak between the Trans and Engine. Its not coming down from the value cover. I note slight leakage showing on the right rear corner and I can see in the bell housing window a drip forming from the rear seal carrier bolt. Suggestions on cause and if its the rear main seal how tough is it to get at (Bentley says R&R trans and support engine from above (does any one have a line on securing the engine support bar to lift the engine? and cost?) thanks for your insight and expertise.

[mforce]

My leaks was coming from the upper corner of the valve cover running down my lines making mine look like the rear seal we bad but turned out they weren't. Are you sure it's not the valve cover gasket? Just a thought. Good luck on it and a bump for you.

[kenskornerstone]

Yeah, I heard the valve cover gasket was notorious for a leak but I can't detect it. Which upper corner was your valve gasket leaking from. Do you check from underneath or on top to detech the leak. thanks

[mforce]

I looked from underneath then I had a mirror that I had with an extension on it and it was the passanger side rear corner that was leaking

[gtx510]

you could try some www.auto-rx.com and see it that helps?

[PENER]

make sure it is not the oil filter stand gasket that leaks! it's a very common failure. I ended up replacing the oil pan gasket (very hard on I6s !!!) before I realized it was oil filter stand gasket that leaked. it would leak onto the top of the oil pan first (it's on the right side whe you look at it or driver side) and the either to the side or to the back.

[slycapt]

Just wrapped up some work to resolve a pesky oil leak. Unfortunately it still leaks, yet there is more to this story. This car is a '00 528i with about 80k mileage.

It appears the gasket behind the oil filter housing, which BMW calls the Aggregate Support w/ Oil Filter, is prone to leakage. This looks a lot like a pan gasket leak.

I first cleaned everything up, and replaced the Oil Filter cover O-ring just to be sure it wasn't something this easy. It wasn't.

Replacing the agg support gasket isn't too bad of a job, and also provides an opportunity to replace a hose or two, and get one of those deep inside the engine looks that you can't see very well from above.

Also once you get everything apart (remove air box, unbolt fan leave in shroud, remove water pump drive belt, remove alternator, set aside power steering oil carrier (reservoir), unbolt and set aside power steering pump) you can see why this gasket is prone to leakage. Aside from being a cheap gasket, it gets hot and the support carries a lot of load from the accessories and drive belt load.

While I had this all apart, I replaced the vent pipe hose that runs off the VANOS and into the pressure regulating valve. This is a tough hose to get to, and was very brittle. Also replaced the suction line to the power steering pump. It was rock hard, and seeping.

While I had the alternator out, I gave it the once over. Seemed to spin ok, and had no previous known issues. I pulled the plastic cooling housing and was surprised to find it full of small leaves and various debris. This could have been a latent short circuit waiting to occur.

Gave the engine a good cleaning while the access was good. This certainly helps to observe the results of your work, and to keep an eye on leaks in general. Unfortunately this area still leaks, and I am bummed.

When I compared the old gasket with the new one, the new one was almost twice as thick. The old one barely protruded from the support housing, as it was compressed and set. It was quite hard as well. I thought this was a no-brainer of fix. New gasket installed, snug it up properly, no more leak. Not the case.

Is there anyone out there with some helpful experience with this gasket/repair? I do not believe the gasket has a pinch or crip as is seats very securely in groove. This is one of those nuisance leaks, which drives us bimmer fantantics crazy.

[kenskornerstone]

Leaks resolved by changing the Oil Filter Housing Gasket (you guys were right) also needed to change the oil pan gasket as the oil pan gasket can leak at the corners as there is a seam at each corner and this is usually the first place an oil pan gasket leak will occur. Pretty big job dropping the front suspension (sub frame) after suspending the engine (engine support).

[champaign777]

crazy staff on 80k miles

[jase007]

For reference: here is a pic of the passenger right rear side of the junction of the oil pan, block and rear main carrier removed when I did my clutch (rear main seal, etc..) recently:

oil pan gasket edge2 (600 x 450).jpg

Bentley says to use high temp rtv along bottom of rear main seal carrier and top of metal oil pan gasket. That is what I did.

It is also recommended to clean out the threads of the old thread sealant (yellow in crank for flywheel bolts and blue for rear main seal carrier bolts - visible in picture) before re-coating carrier bolt threads with new sealant (flywheel bolts are one time use and new come with yellow thread sealant on them).

No leaks since I did the job (had 170,xxx on original clutch, DMF, seals, etc..).

I did NOT have any pan leaks and only slight dripping from RMS area before I went in there to do the full clutch, engine seals, transmission seals, bushings, etc...

I had already replaced the valve cover gaskets when I did the beisan dual vanos seals for my M52tu motor (HIGHLY recommended).

I have not yet replaced the oil filter housing gasket ... but I know it is coming as well as all the hoses for the pressure regulating valve / CCV / CVV and CVV (crankcase ventilation valve) itself.

Hope this helps for reference.

[tpseed]

I need to do this too as my '98 528 has a slow leak somewhere in the same general area of the oil filter housing.

I found a very good DIY written by Bryan H at bmwtips.com and is similar to slycapt's description of the work.

http://www.bmwtips.com/tipsntricks/oil/housing.htm

[BMWe34CMM]

i just had my stand gasket replaced and i still smell oil with the heat on AUTO, seems like when its at the top of the heating cycle is when i smell it. Should i replace the cabin filters? The reason why i changed that leaking gasket was because is because there was a strong oil smell when i would put the heat on. The valve cover gasket was replaced almost a yr ago when i did my VANOS Seals. So i doubt it could be that. do you guys think that the smell is still in the system. Its killing me and nauseating my girlfriend. Any ideas?

[jase007]

Can you see any leaks?

I've replaced my oil filter stand/housing gasket since I last posted as well as my CVV (crankcase vent valve) and related hoses. I never experienced an oil smell ...

If you are getting a smell ... there has to be a leak and/or oil burning somewhere under the hood ... on headers, etc...

Time to break out the flashlight and check it out.

[BMWe34CMM]

hmmmm, i also have a putt'ing sound coming from what i thought was a exhaust leak in the front. Is it possible that there is still a oil smell in the filters or just on the engine still. i have not checked under but just visual inspecton fromt the top... its just really unfortunate that i spent 250$ on doing that and i still have the same issue.

[cnn]

To add to this thread:

I thought I had oil pan gasket leak and almost tempted to replace the oil pan gasket until I did more research and find out that the oil pan gasket in the I6 lasts much longer and usually does not leak until 200K or so.

I then replaced the: oil filter housing gasket + sealed the 2 freeze plugs in the back of the O.F. Housing.
Now it is bone dry. Total cost $10!

If you have wrenched before then this is the DIY:
http://forums.bimmerforums.com/forum/showthread.php?t=1350178

[jeremy339]

I had a problem with my 2001 530i always leaking oil. I checked the engine and saw that the left-driver side of the engine block was wet with oil. After further investigation; I found that it was the oil filter housing seal that was leaking (common problem). I replaced the seal ($20.00 from the stealer) and I also placed some high temp. sealant around the gasket for insurance. So far all is good.

YOu would have to remove the air box and the alternator to get to the oil filter housing. Make sure you disconnect the battery first!

I usually get my OEM parts from Partsgeek.com. The customer service is good. I received my order with one part and they send it 2 days later-no hassle.

[Gh0st Agent]

So, I have an occasional oil leak. It happens only if I drive aggressively, and once coming to a stop I notice smoke coming from under the hood for just a second and then I will smell the oil for a second as well and then everything goes back to normal. I cannot notice smoke or smell during drive, but that doesn't mean it isn't there. My car almost doesn't even consume oil whatsoever, so this must be happening only when driving fast and furious. It is not coming from the valve cover since I just replaced the gasket and don't see any oil around.

I am having a hard time finding this leak so I though maybe someone had a similar situation going on and can advise?

[crazy4trains]

Valve cover gasket. Classic signs.

Also, tell us how many miles on the car and any other pertinent info.

[Gh0st Agent]

Valve cover gasket. Classic signs.

Also, tell us how many miles on the car and any other pertinent info.

I just changed ignition coils, boots, spark plugs, VANOS seals and the valve cover gasket. I don't see any leaks around valve cover so far. I have 134k on my car. I should point out that the smoke almost always comes out on a passenger side; not sure if that is due to an air circulation under the hood or not.

[ViolinARC]

I just changed ignition coils, boots, spark plugs, VANOS seals and the valve cover gasket. I don't see any leaks around valve cover so far. I have 134k on my car. I should point out that the smoke almost always comes out on a passenger side; not sure if that is due to an air circulation under the hood or not.

Not sure but it looks like you have the 530? On the 540, we have an external timing chain tensioner and if it's replaced without doing the crush washer, it can leak. It is on the front right side corner (passenger side) of the engine just under the valve cover for us...

[Gh0st Agent]

Yes, I have a 2002 530i.

Before I changed the valve cover gasket I noticed lots of oil on one of those heat shields that come with the exhaust manifold. It is the back one and it was very oily and there was some oil on my O2 sensor as well. Heat Shield.JPG

I thought it was leaking due to bad valve cover gasket, but now after changing it and still have the same issue I am getting confused. Is there anything else above that heat shield that can potentially leak besides the cover gasket? Again, we are talking about the heat shield closer to the firewall.

[530e39]

If you have other leaks, the valve cover gasket will start leaking again in no time. Vacuum leaks will induce crank case pressure, and it will blow again. I did my vcg before I replaced my ccv, and it leaks more oil now than before... Do a smoke test, and address the leaks all at once.

[kgeorge81980]

I replaced the valve cover gasket on my 2.5 also thinking this was where my leak originated due to pooled oil on the same heat shield tray. I too am still having oil drip from the passenger side rear motor. Slow leak drips onto the exhaust collector where all 4 pipes come together.

[kgeorge81980]

Update on how i cure oil leak...i added 1/8" washers under the original washers on the valve cover hold down nuts to help them pull down tighter after the nuts bottomed out on the studs. Im unsure if the studs in the head needed tightened i didnt want to remove the valve cover for a third time to check.