Oil Found On Transmission Bellhousing

Filecabinet39 · 05-27-2023, 04:52 PM

I have a 2015 m235 with 72k miles on it. I took it in today for an oil change at the dealership, and they mentioned they found some oil on the transmission bellhousing, but couldn’t locate the source of the leak. They recommended a diagnostic, which I have scheduled for a few weeks from now, but I attached the picture from the inspection video they sent to this post. I was wondering if from the picture anyone could provide any insight into the likely source of the problem. I know there are some typical issues with oil leaks on the m235, I just don’t have enough experience with them to know if it’s going to be a serious issue or one that I can wait to fix for awhile. Again, I’m not an expert so any help or information is appreciated.

celsdogg · 05-27-2023, 05:47 PM

Rear main seal maybe? Unless they can find it leaking or weeping from the outside and dripping down, that'd be my guess.

overcoil · 05-27-2023, 06:02 PM

Valve cover leak on mine initially looked like rear main seal.

celsdogg · 05-27-2023, 06:45 PM

Quote:

Originally Posted by overcoil

Valve cover leak on mine initially looked like rear main seal.

That's what I was alluding to, it's super easy to see it's the valve cover so I'd assume they'd be able to see it on the side of the head and block. Fairly easy for a tech to deduce.

overcoil · 05-27-2023, 10:59 PM

As I recall on my 2015 235 6-speed it wasn’t easy even for the tech. They wanted me also to bring back for diagnostic.
The valve cover on the exhaust side, I think is obscured.
Eventually mine started dripping and causing wispy smoke on my exhaust plus some fumes started drifting into the cabin.
I only have my phone but I posted a video of the smoke on a thread here. Do a search and I’ll also try to find and link to it.

fiveightandten · 06-01-2023, 02:38 PM

That looks clean above the bell housing, so it would lead one to suspect either the rear main seal, or a transmission fluid leak from the input shaft seal. It’s very difficult to tell the difference between these without removing the transmission.

The best thing to do is clean everything off, then drive for a bit to see where the leak is originating. If it’s confirmed from inside the bell housing, the transmission will have to come down and you’d just have both seals replaced (and probably a clutch job as well while you’re in there).

05-27-2023, 04:52 PM	#1
Filecabinet39 Registered 0 Rep 1 Posts Drives: BMW M235, BMW X1 Join Date: May 2023 Location: Kansas City iTrader: (0)	Oil Found On Transmission Bellhousing I have a 2015 m235 with 72k miles on it. I took it in today for an oil change at the dealership, and they mentioned they found some oil on the transmission bellhousing, but couldn’t locate the source of the leak. They recommended a diagnostic, which I have scheduled for a few weeks from now, but I attached the picture from the inspection video they sent to this post. I was wondering if from the picture anyone could provide any insight into the likely source of the problem. I know there are some typical issues with oil leaks on the m235, I just don’t have enough experience with them to know if it’s going to be a serious issue or one that I can wait to fix for awhile. Again, I’m not an expert so any help or information is appreciated. Attached Images
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05-27-2023, 05:47 PM	#2
celsdogg E4 Mafia 323 Rep 412 Posts Drives: E30, E36/5, E46, F22, F30 Join Date: Apr 2018 Location: MD iTrader: (0) Garage List 1990 BMW 325i [0.00] 1998 BMW 318ti [0.00] 2003 BMW 325i [0.00] 2015 BMW 335i [0.00] 2015 BMW M235i [0.00]	Rear main seal maybe? Unless they can find it leaking or weeping from the outside and dripping down, that'd be my guess. __________________ Squad - '90 E30 325i MT (225k) \| '98 E36/5 318ti MT (153k) \| '03 E46 325i MT (152k)\| '15 F22 M235i MT (60k) \| '15 F30 335i MT (80k) KIA - '91 E30 325i AT (146k) \| '02 E46 325i MT (212k) Bring back the purple M stripe
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05-27-2023, 06:02 PM	#3
overcoil Major General 3074 Rep 5,577 Posts Drives: M235i 6spd Join Date: Dec 2013 Location: Mid-Atlantic iTrader: (0)	Valve cover leak on mine initially looked like rear main seal.
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05-27-2023, 10:59 PM	#5
overcoil Major General 3074 Rep 5,577 Posts Drives: M235i 6spd Join Date: Dec 2013 Location: Mid-Atlantic iTrader: (0)	As I recall on my 2015 235 6-speed it wasn’t easy even for the tech. They wanted me also to bring back for diagnostic. The valve cover on the exhaust side, I think is obscured. Eventually mine started dripping and causing wispy smoke on my exhaust plus some fumes started drifting into the cabin. I only have my phone but I posted a video of the smoke on a thread here. Do a search and I’ll also try to find and link to it.
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06-01-2023, 02:38 PM	#6
fiveightandten Private 108 Rep 79 Posts Drives: F22 M235, E36 M3, E30 325, E90 Join Date: May 2010 Location: Connecticut iTrader: (0)	That looks clean above the bell housing, so it would lead one to suspect either the rear main seal, or a transmission fluid leak from the input shaft seal. It’s very difficult to tell the difference between these without removing the transmission. The best thing to do is clean everything off, then drive for a bit to see where the leak is originating. If it’s confirmed from inside the bell housing, the transmission will have to come down and you’d just have both seals replaced (and probably a clutch job as well while you’re in there).
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