Severe Oil Leak, Pan Gasket or Rear Main Seal? Pics Included.

E90convert · 10-19-2019, 12:07 PM

Hey All - For the past few months my 2008 E92 335xi 6MT sprung a leak. It's finally gotten bad enough that I am investigating. Lost about 1/2qt in 300 miles and about 20 days! Car has 130k miles on it and is my stock daily driver. Not driven hard, but sees Ohio weather.

I took the subframe brace off and splash guards and there is alot of oil where. From the front of the oil pan, to the center xDrive unit. On the belly tray, it looks to be biased toward the passenger side of the vehicle. Area around the turbos is dry.

I wiped things down and started the car and found it starting to drip off an oil pan fastener, located near the clutch housing inspection cover. I can't determine if it is the rear main seal, or the pan gasket. I have a hunch it is the pan gasket, and here are my thoughts.

-Front of the oil pan is coated
-Dripping from the oil pan fastener, not the inspection hole in the center
-Biasing toward one side (see belly pan picture) not evening distributed if it was only leaking from the inspection hole.
-Looking at the flywheel in the inspection hole, looks dry.
-Clutch performance is find, no slipping.

What are your guys thoughts?

MightyMouseTech · 10-19-2019, 04:53 PM

Most likely the oil pan gasket. Have never seen a leaking rear main seal.

CTinline-six · 10-19-2019, 06:35 PM

+1 on the oil pan gasket

Also, the oil on that bolt is just sitting there because it's the lowest point on the engine. The oil is leaking down from the pan gasket.

Oolien · 10-19-2019, 09:50 PM

Looks like oil pan, here's a video of my cars mess underneath that was indeed the oil pan. looks like the oil is collecting in the same spot as yours (

) and with 130k miles on it that gasket is probably quite brittle and is probably starting to leak. My car only had 80k miles on it and the gasket was like snapping tree bark.

E90convert · 10-20-2019, 07:26 AM

Can anyone link me to a DIY for an oil pan on here? My Bentley manual doesn’t have the oil pan removal. Must be too complex ha!

Efthreeoh · 10-20-2019, 07:37 AM

Quote:

Originally Posted by E90convert

Can anyone link me to a DIY for an oil pan on here? My Bentley manual doesn’t have the oil pan removal. Must be too complex ha!

We have a great DIY section. Almost every repair required for the E9X is covered there. This is your one "get out of jail free" card.

https://www.e90post.com/forums/showthread.php?t=1180020

Like MightyM said, rare for a rear crank seal to leak. Not rare for the oil pan gasket to leak. The rear of the pan protrudes into the bell housing behind the flywheel. When the rear of the pan starts to leak, it makes a mess inside the bellhousing and makes it appear like the rear crank seal is leaking.

10-19-2019, 12:07 PM	#1
E90convert Lieutenant 167 Rep 428 Posts Drives: F87 M2 DCT, F15 X5 Join Date: Dec 2014 Location: Columbus, Ohio Metropolitan Area iTrader: (0)	Severe Oil Leak, Pan Gasket or Rear Main Seal? Pics Included. Hey All - For the past few months my 2008 E92 335xi 6MT sprung a leak. It's finally gotten bad enough that I am investigating. Lost about 1/2qt in 300 miles and about 20 days! Car has 130k miles on it and is my stock daily driver. Not driven hard, but sees Ohio weather. I took the subframe brace off and splash guards and there is alot of oil where. From the front of the oil pan, to the center xDrive unit. On the belly tray, it looks to be biased toward the passenger side of the vehicle. Area around the turbos is dry. I wiped things down and started the car and found it starting to drip off an oil pan fastener, located near the clutch housing inspection cover. I can't determine if it is the rear main seal, or the pan gasket. I have a hunch it is the pan gasket, and here are my thoughts. -Front of the oil pan is coated -Dripping from the oil pan fastener, not the inspection hole in the center -Biasing toward one side (see belly pan picture) not evening distributed if it was only leaking from the inspection hole. -Looking at the flywheel in the inspection hole, looks dry. -Clutch performance is find, no slipping. What are your guys thoughts? Attached Images __________________ ‘18 F87 M2 DCT '17 F15 X5 xDrive35i M-Sport Sold in 2023 '12 F30 335i 8AT Sport Line Sold in 2020 '08 E92 335xi 6MT Sold in 2016 '08 E90 335i 6MT - FBO
	Appreciate 0 Tweet Quote

10-19-2019, 04:53 PM	#2
MightyMouseTech Major General 4338 Rep 6,196 Posts Drives: 13 135i 6MT LeMans Blue MSport Join Date: Feb 2013 Location: Ottawa, Canada iTrader: (0)	Most likely the oil pan gasket. Have never seen a leaking rear main seal.
	Appreciate 0 Quote

10-19-2019, 06:35 PM	#3
CTinline-six Hoonigan 6893 Rep 3,001 Posts Drives: '09 328i, '98 Wrangler Join Date: Dec 2016 Location: Connecticut iTrader: (0) Garage List 2009 BMW 328i N51 [0.00]	+1 on the oil pan gasket Also, the oil on that bolt is just sitting there because it's the lowest point on the engine. The oil is leaking down from the pan gasket. __________________ "Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should." -Dr. Ian Malcolm, Jurassic Park
	Appreciate 0 Quote

10-19-2019, 09:50 PM	#4
Oolien Enlisted Member 3 Rep 47 Posts Drives: 08 bmw 335xi n54 Join Date: Apr 2019 Location: canada iTrader: (0)	Looks like oil pan, here's a video of my cars mess underneath that was indeed the oil pan. looks like the oil is collecting in the same spot as yours ( ) and with 130k miles on it that gasket is probably quite brittle and is probably starting to leak. My car only had 80k miles on it and the gasket was like snapping tree bark.
	Appreciate 0 Quote

10-20-2019, 07:26 AM	#5
E90convert Lieutenant 167 Rep 428 Posts Drives: F87 M2 DCT, F15 X5 Join Date: Dec 2014 Location: Columbus, Ohio Metropolitan Area iTrader: (0)	Can anyone link me to a DIY for an oil pan on here? My Bentley manual doesn’t have the oil pan removal. Must be too complex ha!
	Appreciate 0 Quote