Oil Leak Got Worst After Replacing Gasket!

E90convert · 12-24-2019, 09:42 PM

Hi All!

I have a 2008 E92 335xi 6MT. The car has 130k on it and is unmodified and my daily driver. As with all N54s (and most BMWs) it has had its fair share of maintenance over the years. Here is a list of what has been done recently: Valve cover gasket, oil filter housing gasket, waterpump/thermostat at 111,000 miles.

About 4 months ago, the car seemed to develop an oil leak. I noticed it when I left the car at an airport for a week, and came back to smelling oil when coming to a stop after driving. It would leak about 1/4qt a month. Then slowly getting worst to about 2/3qt a month. After that I decided it is too leaky and needs to be fixed. I got under it and there was oil everywhere. I laid under the vehicle while it was running for a bit and it seemed like it was either the oil pan gasket or rear main seal. There was some oil drips building from bolts around the oil pan gasket, so I diagnosed it as such. A BMW master tech who does side work changed the gasket for me.

The oil leak is now much much worst. I seemed to have lost 1qt of oil in 20 miles. The oil leakage seems to be dependent on how hard I drive the car. Lately I have been driving very easy (shifting around 2,000 RPM accelerating slowly). It looses oil less. But still lost 1/4qt in 50 miles. Of course there is always the question of quality workmanship from the tech. He took the car back and laid under it again and said it was the rear main seal leaking.

Now I have a theory here. Could the PCV system be clogged up enough that it crank case pressure is high and causing oil to be blown out the rear main seal? Now that the oil pan gasket is sealed nice and tight, the pressure is finding the path of least resistance. To replace the PCV system is around $350 (valve cover, gasket, rear tube). Is it worth try to fix the PCV first or just pay someone to replace the rear main seal?

E90convert · 12-26-2019, 08:18 AM

Bump

Idea: should I check the leak with the oil fill cap closed? And then open it, and see if the leak changes? When I open the oil fill now, there is definitely some vapors puffing out.

Bent_remy · 01-19-2020, 07:34 AM

You should repost this in the general forum. You may find a quicker response there.

12-24-2019, 09:42 PM	#1
E90convert Lieutenant 162 Rep 422 Posts Drives: F87 M2 DCT, F15 X5 Join Date: Dec 2014 Location: Columbus, Ohio Metropolitan Area iTrader: (0)	Oil Leak Got Worst After Replacing Gasket! Hi All! I have a 2008 E92 335xi 6MT. The car has 130k on it and is unmodified and my daily driver. As with all N54s (and most BMWs) it has had its fair share of maintenance over the years. Here is a list of what has been done recently: Valve cover gasket, oil filter housing gasket, waterpump/thermostat at 111,000 miles. About 4 months ago, the car seemed to develop an oil leak. I noticed it when I left the car at an airport for a week, and came back to smelling oil when coming to a stop after driving. It would leak about 1/4qt a month. Then slowly getting worst to about 2/3qt a month. After that I decided it is too leaky and needs to be fixed. I got under it and there was oil everywhere. I laid under the vehicle while it was running for a bit and it seemed like it was either the oil pan gasket or rear main seal. There was some oil drips building from bolts around the oil pan gasket, so I diagnosed it as such. A BMW master tech who does side work changed the gasket for me. The oil leak is now much much worst. I seemed to have lost 1qt of oil in 20 miles. The oil leakage seems to be dependent on how hard I drive the car. Lately I have been driving very easy (shifting around 2,000 RPM accelerating slowly). It looses oil less. But still lost 1/4qt in 50 miles. Of course there is always the question of quality workmanship from the tech. He took the car back and laid under it again and said it was the rear main seal leaking. Now I have a theory here. Could the PCV system be clogged up enough that it crank case pressure is high and causing oil to be blown out the rear main seal? Now that the oil pan gasket is sealed nice and tight, the pressure is finding the path of least resistance. To replace the PCV system is around $350 (valve cover, gasket, rear tube). Is it worth try to fix the PCV first or just pay someone to replace the rear main seal? __________________ ‘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 Last edited by E90convert; 12-25-2019 at 06:52 AM..
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12-26-2019, 08:18 AM	#2
E90convert Lieutenant 162 Rep 422 Posts Drives: F87 M2 DCT, F15 X5 Join Date: Dec 2014 Location: Columbus, Ohio Metropolitan Area iTrader: (0)	Bump Idea: should I check the leak with the oil fill cap closed? And then open it, and see if the leak changes? When I open the oil fill now, there is definitely some vapors puffing out.
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01-19-2020, 07:34 AM	#3
Bent_remy Enemy of viscosity and thermal breakdown 138 Rep 278 Posts Drives: N54 E93 6MT Join Date: Oct 2014 Location: North Texas iTrader: (1)	You should repost this in the general forum. You may find a quicker response there. __________________ 02' E46 S54 M3 6MT OEM+, Apex FL-5, RIP 09' E93 N54 6MT, Smarttop, Lux V5, JB4 G5 ISO, BMS DCI, Black ER CP, Tial BOV
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