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Recently purchased an 07 335I 84k miles. Car has an oil leak coming from the right rear of the pan,recent owner had the pan gasket replaced already. I assumed they over/under torqued,or something to that affect. One of the longer rear bolts had 2 small washers on it...something was up there must have over stretched the bolt.. Anyways I replaced the gasket again this weekend, old gasket looked good but who knows. No leaks hours after adding oil, ran it a cpl minutes was fine. Ran it another 5 minutes started leaking from the same damn spot! I am assuming only other cause must be the rear main seal? Makes since it didn't start leaking until 4-5 minutes after running, pretty bad leak. Seems odd the rear main would be bad with only 84k miles though,engine runs flawless no CEL's etc. No CCV issues or vacuum though oil cap
Thoughts? Plan is to drop the trans next weekend...
Member
I've been through this same situation before with an N55 and it was the rear main seal from the start. One thing that was different from the oil pan leak, I could see oil coming from the bed plate seam in the R/R of the motor. The seam a few inches above the oil pan seam. The rear main actually sits right in the middle of the bed plate and engine block, so the oil tends to run down that seam.
Jbird
The seal is only 11 years old, so it could be bad
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Well there is nothing else left to do but drop the transmission now....Originally Posted by jclausen
Member
Anyone know the torque specs on the flexplate and torque converter bolts?
Member
Are you gonna eat that?
Member
Thank you!
Member
Update, was def the rear main seal that was leaking. I should have took a picture as it was half out and we pulled it out with our fingers.... New seal was an Elring that was not spring loaded. It was crap in my opinion and needless to say leaked immediately. Ended up using an aftermarket Federal Spring loaded seal with no issues. So after installing my transmission twice in 1 weekend I got pretty good at it! 6 hours 2nd time around complete job. What a PITA but I now have a new oil pan gasket and rear main seal done in my car.
Member
I don't know a lot about the N54, except I know it has a complex CCV system in the cam cover to use different paths for low and high manifold pressures.
My son's VW Tiguan turbo blew a rear main seal after the CCV system failed and allowed too much pressure (perhaps boosted intake pressure) into the crankcase. While you're at it, I'd make sure your CCV system is working properly.
Member
Originally thought about that to but no vacuum at the oil cap and no CEL's at all. Previous owner may have beat on it a bit, it does have an injen Intake on it and most likely had or has a tune in it.
Member
Wait! Do you mean it has no vacuum at the oil cap or dipstick? That's not normal for most Bimmers (in my experience), and pretty sure that's not normal for that engine. Normally with the cap or dipstick open one would get a slight vacuum, some engine stumbling, and eventually a code. If I were you, I'd worry about that as a contributing cause to your old rear main seal blowing, and potential cause for making the new one fail.
In short, if the system isn't pulling in crankcase air at idle, as it's supposed to, then what is it doing when you're on boost and blow-by gasses are high? Is pressure building up in the crankcase? Or does the system work OK when it really needs to, just not at idle. Key questions for you.
My nephew has an e60 535 with that engine, and I've been reading up on how to help him with a catch can. I have a good BMW pdf on how the system works, if you'd like it. Not simple. Just send me a pm with your email address and I'll send the pdf to you. I can also share many good online links I've found for the system and how to understand/modify it.
Last edited by R Shaffner; 04-10-2019 at 07:07 PM.
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