[BimmerNugget]

Hi there,

Hope you all had a wonderful Thanksgiving. I was doing and oil change and tranny fluid change yesterday and I noticed some oil between where the back of the engine block meets the transmission.

Is this a rear main seal leak? How serious is it? Can I get away with driving it for another year or so and just selling it or should I get it fixed asap?

See pics:

View post on imgur.com

View post on imgur.com

[RocketSurgeon]

My rear main seal blew out of the engine and gushed oil really bad. Mine was so bad that the car couldn't be driven, it would lose a quart in well under 100 miles. Check other possibilities first like oil-filter housing gasket, valve cover gasket, oil pan gasket, etc. I always recommend fixing problems as they appear so that you don't accumulate a massive list of maintenance requirements. You can continue to drive it as long as you keep the oil level up. I've tried a variety of stop-leak and gasket sealers, they don't work. I spent $700 to have my rear-main seal done.

[BimmerNugget]

Originally Posted by RocketSurgeon

My rear main seal blew out of the engine and gushed oil really bad. Mine was so bad that the car couldn't be driven, it would lose a quart in well under 100 miles. Check other possibilities first like oil-filter housing gasket, valve cover gasket, oil pan gasket, etc. I always recommend fixing problems as they appear so that you don't accumulate a massive list of maintenance requirements. You can continue to drive it as long as you keep the oil level up. I've tried a variety of stop-leak and gasket sealers, they don't work. I spent $700 to have my rear-main seal done.

At what mileage did your RMS leak occur? I'm assuming $700 is indy prices?

My VCG is dry as a mofo and so is my oil pan. I just did an oil change and inspected the seams of the pan like crazy. Not a drop of oil.

There is only oil where the transmission meets the back of engine block.

[RocketSurgeon]

Originally Posted by BimmerNugget

At what mileage did your RMS leak occur? I'm assuming $700 is indy prices?

My VCG is dry as a mofo and so is my oil pan. I just did an oil change and inspected the seams of the pan like crazy. Not a drop of oil.

There is only oil where the transmission meets the back of engine block.

I got the car with 107k and the RMS was blown out when I bought it. I bought that car non-running for $3900 back in 2015. I had the RMS replaced at a local transmission shop. I've done rear main seals before, but it epically sucks to do it on jack stands. All the local Euro shops were north of $1500, so I was seriously considering spending that money on a lift for DIY.
Rear main seal leaks aren't exactly common on the n54, but they aren't rare either.

[tlow98]

N52 RMS leaks are extremely uncommon. It is, however, very common for a leak to develop on the backside of the oil pan gasket, which mimics a RMS leak.

Just a heads up before you go too deep down the RMS black hole.

How bad is the leak? A slow seeping oil pan can stay in the same state for years... and doesn't necissarily need to be replaced.

[BimmerNugget]

Originally Posted by tlow98

N52 RMS leaks are extremely uncommon. It is, however, very common for a leak to develop on the backside of the oil pan gasket, which mimics a RMS leak.

Just a heads up before you go too deep down the RMS black hole.

How bad is the leak? A slow seeping oil pan can stay in the same state for years... and doesn't necissarily need to be replaced.

Hmm...I guess I'll have it get it onto jack stands again and remove both plastic panels to get a better look. I'm not sure how much or how fast it was leaking but there was definitely a leak somewhere. Oddly enough, there wasn't any oil on the plastic panels covering the transmission fluid pan.

[bluemidas]

Originally Posted by BimmerNugget

Hmm...I guess I'll have it get it onto jack stands again and remove both plastic panels to get a better look. I'm not sure how much or how fast it was leaking but there was definitely a leak somewhere. Oddly enough, there wasn't any oil on the plastic panels covering the transmission fluid pan.

Hey BimmerNugget, did you figure out what this was/have it fixed? I have something similar on my car so would like to hear what you were able to do to resolve it!!!

[BimmerNugget]

Originally Posted by bluemidas

Hey BimmerNugget, did you figure out what this was/have it fixed? I have something similar on my car so would like to hear what you were able to do to resolve it!!!

Ohh boy. I’ve since sold this E90 328i. I’m in an E90 M3 now. Never got it diagnosed if its a RMS leak or not.

The leak was so slow it didn’t really matter. Just drive it til you see oil stains on your driveway.