[naxzz9]

2007 335i n54 automatic. not sure if the issue is rear main seal or oil pan gasket or something else.

[ken335AZ]

Clean it up around the oil pan then run the engine with the car on some wheel ramps or jack stands and try to narrow it down. Hard to tell without pics. The return lines leak on these cars with age, you can also get oil leaking from the o rings on the feed lines. Both these leaks tend to drip down in the same areas where the oil pan leaks(passenger rear). If you clean the area and it continues to leak on the back side of it between the bellhousing and block or bottom corners it's still a 50/50 on oil pan or rear main. Only way to truly know is to pull the transmission and see if there is oil on the back of the block... or do the PITA job of swapping out the oil pan gasket and replace all the pan bolts then see if there's still a leak.

[ken335AZ]

Good idea if you plan on the tackling the oil pan then also do the valve cover gasket, pcv, vent hose, and rear main all at once to ensure no leaks anywhere. Also check around the oil lines to and from turbo and replace accordingly. Your motor is 10 years old and the popular seals/gaskets are mostly around the corner from leaking if not already.

[dyezak]

Just clean it up and use a UV oil leak detection kit. It's UV dye that you add to your oil, then use a black light and special glasses to see where the leak is coming from. Easy peasy.

[musa]

You're having a massive leak! The oil is dripping continuously as you watch. This appears not to be engine oil. It looks like transmission oil. Don't drive or even start that car!

[NoQuarter]

I Don't think a UV dye is necessary here!

As was said above, this is a massive leak and needs to be fixed immediately.

[naxzz9]

i just changed the oil pan gasket. leak has not stopped. anyone know of a DIY for the rear main seal?

[musa]

Try https://www.newtis.info/

[NoQuarter]

Originally Posted by naxzz9

i just changed the oil pan gasket. leak has not stopped. anyone know of a DIY for the rear main seal?

Remove transmission

Drill small hole(s) into rear main seal. Hook seal with small tool such as an angled pick and pull it out.

Lube new seal and tap it in with old seal and small hammer until seated

Replace tramsmission. But first... Make sure that is motor oil that is leaking and not trans fluid.

[mweisdorfer]

Originally Posted by NoQuarter

Remove transmission

Drill small hole(s) into rear main seal. Hook seal with small tool such as an angled pick and pull it out.

Lube new seal and tap it in with old seal and small hammer until seated

Replace tramsmission. But first... Make sure that is motor oil that is leaking and not trans fluid.

I know of one for an e46, which may give you a decent idea on how to proceed, but I have never seen a diy for rear main seal, on an e90.

I think using UV oil kit would be smart idea, and it would tell you for sure if it's oil vs tranny fluid. Although tranny fluid has a distinct smell.

I think it can be done on jack stands, with a Transmission jack.

[Taylor M]

Originally Posted by NoQuarter

Remove transmission

Drill small hole(s) into rear main seal. Hook seal with small tool such as an angled pick and pull it out.

Lube new seal and tap it in with old seal and small hammer until seated

Replace tramsmission. But first... Make sure that is motor oil that is leaking and not trans fluid.

Good advice. You can run a small screw in the seal as well and pull it with vice grips. Also I shaved a piece of pvc pipe, 3 or 3.5 inch something or the other, and used that to tap it in. Gave me a little more material to slap on with the mallet.