[Dabozo]

Hi guys, was a nice dry day here today so figured id take the car out for a spin...only to return with a smoking car. Upon inspection im leaking a lot of oil. Had done an oil change weeks earlier and was ready to kick my own ass for not tightening something properly...however, after removing engine cover, I have oil on top of the engine. You guys think this may be a cracked valve cover or worn gasket. Of course I will have to tow the car to my mechanic to be sure but was hoping for some arm chair mechanic opinions from you all...

[F87source]

Originally Posted by Dabozo

Hi guys, was a nice dry day here today so figured id take the car out for a spin...only to return with a smoking car. Upon inspection im leaking a lot of oil. Had done an oil change weeks earlier and was ready to kick my own ass for not tightening something properly...however, after removing engine cover, I have oil on top of the engine. You guys think this may be a cracked valve cover or worn gasket. Of course I will have to tow the car to my mechanic to be sure but was hoping for some arm chair mechanic opinions from you all...

It's probably your oil filter housing gasket, but it is hard to tell from this one image.

[Dabozo]

Originally Posted by F87source

It's probably your oil filter housing gasket, but it is hard to tell from this one image.

The housing seems fine. Besides, oil is above the housing. On top of valve cover. I’ll try to get in there to try and definitively rule filter housing out. Thanks

[F87source]

Originally Posted by Dabozo

The housing seems fine. Besides, oil is above the housing. On top of valve cover. I’ll try to get in there to try and definitively rule filter housing out. Thanks

Wow that's alot of oil. Yeah not sure where it is coming from.


BTW your coolant level is way too low judging by the first image. You might want to top that up.

This also hints that it could be the oil filter housing gasket, because coolant can leak through there. But typically it won't be coolant leaking because the oil is at a higher pressure and you'd have oil going into the coolant loop. This could be a coolant leak elsewhere and it could be the expansion hose leaking and spraying coolant all over your engine, and not oil. So are you sure that is oil and not coolant?

[ThreeStripes]

Let us know what this traces back to. Also, what’s your current mileage?

[Dabozo]

Current mileage 70000 km

Was busy last night. Going to investigate further today. And will report back. Pretty sure it’s all oil though. Let’s see.

[Dabozo]

welp I think I discovered the origin of the leak... I cleaned up as much of the oil that I could and started the engine and observed..didnt take long to see oil seeping profusely from the oil filter cap. Looks to be a bad o ring.
New o ring (filter kit) has been ordered. lots of oil down below...I'll have to remove the stiffening plate and try and clean things up some more. Luckily, doesn't seem any oil got onto the serpentine belt but will double check.
thanks for your input F87source!

FYI Oil filter and associated O rings were MANN

[ThreeStripes]

Glad ya got it sorted.

[F87source]

Originally Posted by Dabozo

welp I think I discovered the origin of the leak... I cleaned up as much of the oil that I could and started the engine and observed..didnt take long to see oil seeping profusely from the oil filter cap. Looks to be a bad o ring.
New o ring (filter kit) has been ordered. lots of oil down below...I'll have to remove the stiffening plate and try and clean things up some more. Luckily, doesn't seem any oil got onto the serpentine belt but will double check.
thanks for your input F87source!

FYI Oil filter and associated O rings were MANN

No worries, I didn't even think it would be from the cap but yup that'll do it.

Did you replace the o-rings upon changing the filter? The only time I've ever seen these things leak is from reuse of the o-rings.


Btw don't forget to top up your coolant.

[Dabozo]

aside from the initial free oil changes, Ive always done my own and always replace rings with new, oem ones.

Not sure why this happened this time though. Maybe I was lazy and didn't torque properly, can't remember now if I did 🤔 25Nm
Overtightening could/would damage o ring...so its possible I could have goofed.

sure am glad this is the issue and not the valve cover gasket...watched some diy's...wasnt looking forward to it!

and yes, thanks for the coolant reminder🍻

[F87source]

Originally Posted by Dabozo

aside from the initial free oil changes, Ive always done my own and always replace rings with new, oem ones.

Not sure why this happened this time though. Maybe I was lazy and didn't torque properly, can't remember now if I did 🤔 25Nm
Overtightening could/would damage o ring...so its possible I could have goofed.

sure am glad this is the issue and not the valve cover gasket...watched some diy's...wasnt looking forward to it!

and yes, thanks for the coolant reminder🍻

Yup no worries, just make sure you buy oe bmw anti-freeze, and don't forget to dilute it to 50:50 with distilled water.

Did you lube the o-rings with oil? O-rings can punch and bind if they're not lubed.

[Dabozo]

def lubed them...needless to say, ill be paying very close attention with the replacement!!
Thanks for the af advice f87source...saves me from searching up!

[F87source]

Originally Posted by Dabozo

def lubed them...needless to say, ill be paying very close attention with the replacement!!
Thanks for the af advice f87source...saves me from searching up!

yup no worries. You should also consider buying a new oil filter cap, they are known to crack after some age.

You can either go with a new stock cap (DO NOT buy one from Amazon, ebay or aliexpress - the cheap Chinese ones suck in terms of tolerance and bypass quality, buy a genuine BMW cap or from their OEM) or an alluminium one, and if you go aftermarket I recommend the malo industries cap - I have a review outlining why.

[Dabozo]

Good idea! thank you.

[F87source]

Originally Posted by Dabozo

Good idea! thank you.

No problem!

[David.m]

Originally Posted by Dabozo

welp I think I discovered the origin of the leak... I cleaned up as much of the oil that I could and started the engine and observed..didnt take long to see oil seeping profusely from the oil filter cap. Looks to be a bad o ring.
New o ring (filter kit) has been ordered. lots of oil down below...I'll have to remove the stiffening plate and try and clean things up some more. Luckily, doesn't seem any oil got onto the serpentine belt but will double check.
thanks for your input F87source!

FYI Oil filter and associated O rings were MANN

Guess at the last oil change you've accidently installed the cap o-ring in the wrong position. A few months back at a track day another M2 had a similar oil leak, the guy had just done an oil change and you could see his cap wasn't screwed down flush onto the housing, he pulled it off to find the o-ring in the wrong slot. Reminded me of a time I accidently put the o-ring in the wrong slot and had difficulty tightening the cap, took it off and moved o-ring to correct groove & problem fixed.

There are 2 wide adjoining slots at the top of the cap thread, the correct one is smooth all way around where as the wrong one has a couple of raised edges.