[gerrg]

I'm pretty sure I'm in the right forums... I have a 2012 BMW 335i...

Anyways, I'm trying to find the oil leak in my car. it's been leaking for a month or two now but things have been super busy and I haven't had a chance to work on it yet. I've finaly got some time so I put the car up on some ramps, opened the hood and looked around a bit. Please note that I'm lose 1 quart of oil every 2-3 weeks or so.

I noticed a few things, some oil is pooling around the oil filter, as well as a couple places behind and under neith the oil filter (see images with oil pooling circled). I've also noticed some oil residue around the genearl area of the spark plugs (again see images). looking under the engine cover, i could see what looked like oil splater on the underside around where the oil filter is. I remove the under body (which was completly saturated with oil) and saw that it had a single spot where oil was still pooled. Looking underneith the car, pretty much everything had oil on it.

So... any ideas where this might be coming from? I've already ordered a valve cover gasket, oil cooler gasket, and oil filter gasket to replace since that's what i think the problem is, but thought it would be good to get some feed back from people here.

Please let me know if i can clarify anything. Thanks!!

*Note: I tried posting the images to the forum, but it didn't work... so here are the link.s

https://ibb.co/k3gdAG
https://ibb.co/gJ8QqG
https://ibb.co/nzBOcw
https://ibb.co/eeBOcw
https://ibb.co/nQe9Hw
https://ibb.co/cYuWVG
https://ibb.co/fGULPb
https://ibb.co/b6i3cw
https://ibb.co/kmrOcw

[paimon.soror]

miles on the car?

[gerrg]

I knew i forgot something...

It's got 88k on it right now.

[GarlicBread]

Ok so if you see oil around spark plug area your valve cover is leaking. If you see oil around oil filter your oil filter housing gasket is leaking. However unless you're valve cover is cracked I don't see how you would be losing that much oil from just those two gaskets so there is probably one or two more somewhere

[chiefneil]

I just had the oil pan gasket on my 2014 335i replaced, so that's another possibility.

These N55 engines sure do seem more prone to leaking than the engine in my old E46.

[jparnes1]

Oil around the filter is definitely the oil filter housing gasket which is a common problem (is the oil filter cap screwed down sufficiently?) Remember, fluid will travel downward, so if you find a leak on top, you'll also find it down below as it drips.
It's possible this is the cause for oil near the plugs, but that could be a leaky valve cover gasket.
First, see if the oil filter cap needs tightening down. There should be a colored marker on the side of the cap that lines up with a marker on the housing body. If there's no mark, there's a torque spec of 20-ish ft/lbs. That's very light, so a good hand tightening with a wrench is OK if you don't have a torque wrench. If it's tight, then you'll likely need to replace the oil filter housing. This isn't hard if you're so inclined. Clean up all the oil on various parts (break parts cleaner is excellent for this) whether you do the repair or have the shop do it and see if you still have a problem.

[X2 Monstah]

I'd say oil filter housing gasket. Just replaced it on my wife's 128i at 40,000 miles. But a quart every 2-3 weeks seems like quite a bit.

[Billfitz]

Trace the leak with dye.

[Wires]

I'd say you nicked the o-ring on the filter housing (first picture). That is under pressure when the engine is running. Oil will drain downwards, fan/wind will then blow it backwards.

[_bdiddyb_]

You'll be surprised how a tiny leak can have your whole engine drenched in oil. I traced the oil stains all the way up to the highest point in the engine. This led me to the oil filter housing. There are 2 gaskets I had to replaced. When I removed them, they were very brittle. I also had to replace the serpentine belt as oil was all over it. Get if fixed fast because you'll have hours of meticulously cleaning the engine and underbelly of oil -- not fun.

[gerrg]

Thanks for all the replies everyone! it sounds like i'm at least on the right track with changing out the valve cover and oil filter gaskets.

Originally Posted by jparnes1

Oil around the filter is definitely the oil filter housing gasket which is a common problem (is the oil filter cap screwed down sufficiently?) Remember, fluid will travel downward, so if you find a leak on top, you'll also find it down below as it drips.
It's possible this is the cause for oil near the plugs, but that could be a leaky valve cover gasket.
First, see if the oil filter cap needs tightening down. There should be a colored marker on the side of the cap that lines up with a marker on the housing body. If there's no mark, there's a torque spec of 20-ish ft/lbs. That's very light, so a good hand tightening with a wrench is OK if you don't have a torque wrench. If it's tight, then you'll likely need to replace the oil filter housing. This isn't hard if you're so inclined. Clean up all the oil on various parts (break parts cleaner is excellent for this) whether you do the repair or have the shop do it and see if you still have a problem.

Thanks for suggesting this! I'll try to look for the alignment mark when I get home and try to tighten it if anything else. I'll just have to replace the oil filter gasket, right? not the whole housing I would assume. And I was planning on trying to do a good engine clean after all the gaskets are replaced to make things look nice, to get rid of the burning oil smell faster, and to hopefully be able to see if there are any other problems later.

As to cleaning the oil off, is there anyway to clean the undercover of the car? it's like a cloth/cardboard type material it feels like, so I wasn't sure if cleaning this would be practical or not, or if i'd just end up ruining it by all the cleaning.

Thanks again! I'll keep you all posted on how the gasket replacing goes!

[gerrg]

Hey everyone! I replaced the valve Gasket, oil filter housing gasket, and oil coolant gasket and that solved most of the leak. Then i noticed the oil was coming from around the oil filter cap (much more noticeable that it used to). Anyways, I replaced the oil filter and the o-rings and everythings been looking good so far.

I haven't changed an oil filter on a BMW before now (i had a '88 mercury before this so different type of filter all together). Are the o-rings normallly really hard after they've been used? I would have thought they still would have been a little soft, but but the small and large 0-rings were very stiff when i removed the old ones. Figured I'd see if that was normal.

Thanks for all the help with this!

[Orion4]

Originally Posted by gerrg

Hey everyone! I replaced the valve Gasket, oil filter housing gasket, and oil coolant gasket and that solved most of the leak. Then i noticed the oil was coming from around the oil filter cap (much more noticeable that it used to). Anyways, I replaced the oil filter and the o-rings and everythings been looking good so far.

I haven't changed an oil filter on a BMW before now (i had a '88 mercury before this so different type of filter all together). Are the o-rings normallly really hard after they've been used? I would have thought they still would have been a little soft, but but the small and large 0-rings were very stiff when i removed the old ones. Figured I'd see if that was normal.

Thanks for all the help with this!

How many miles since last oil/oil filter change? My experience is with a normal oil change cycle of 7500-10,000 miles, the O-rings are still very flexible. Maybe only a very slight hardening. If they are truly very stiff, then that may indicated excessive heat.

[Billfitz]

Originally Posted by gerrg

the small and large 0-rings were very stiff when i

Not normal. When you put it all together be sure to coat the o-rings with some oil.

[gerrg]

it's been about 6k miles since my last oil change. I'm just wondering if they didn't actually change the o-rings when they changed the filter. I'll do my own oil change this next time and see how things are holding up. Thanks for the input!

[Orion4]

Like Billfitz said: when you do the oil/oil filter change lightly oil the O-ring around the cover housing with clean oil. Just enough the lubricate the O-ring. Prevents the chance of the O-ring tearing or getting nicked and makes screwing the cover down much easier.

[Billfitz]

Originally Posted by gerrg

I'm just wondering if they didn't actually change the o-rings when they changed the filter.

New o-rings come in the box with the filter, so there's no excuse for not putting them in. Some also include a washer for the crank case drain plug, in case you're changing your oil along with the filter.

[yoon_209]

how much should this service cost at an indy shop? around 500?

[F30NFifty5]

_bdiddyb_
Think my leak is coming from the front gasket or damaged threads on the oil cap??

[F30NFifty5]

Originally Posted by jparnes1

Oil around the filter is definitely the oil filter housing gasket which is a common problem (is the oil filter cap screwed down sufficiently?) Remember, fluid will travel downward, so if you find a leak on top, you'll also find it down below as it drips.
It's possible this is the cause for oil near the plugs, but that could be a leaky valve cover gasket.
First, see if the oil filter cap needs tightening down. There should be a colored marker on the side of the cap that lines up with a marker on the housing body. If there's no mark, there's a torque spec of 20-ish ft/lbs. That's very light, so a good hand tightening with a wrench is OK if you don't have a torque wrench. If it's tight, then you'll likely need to replace the oil filter housing. This isn't hard if you're so inclined. Clean up all the oil on various parts (break parts cleaner is excellent for this) whether you do the repair or have the shop do it and see if you still have a problem.

Based on the picture I've attached do you think this leak is coming from the front housing gasket or a damaged oil cap?

[F30NFifty5]

Originally Posted by X2 Monstah

I'd say oil filter housing gasket. Just replaced it on my wife's 128i at 40,000 miles. But a quart every 2-3 weeks seems like quite a bit.

Any insight on where my leak is coming from?? Im thinking it's from the front oil filter gasket but it looks like it could be coming from the oil filter cap.

[Billfitz]

Use the UV dye in the link I posted and you won't need to rely on others looking at photos to find the leak.