Oil leak / sometimes smells of burnt oil - Valve cover gasket? (SOLVED)

[ChapterM3]

Hi all,

As the title states, my valve cover gasket is leaking, although it was replaced 20k miles ago. Here are the symptoms:
From underneath the car:
- Exhaust side of head and block is all oil residue
- o2 sensor has signs of burning oil on it - this seems to have come from oil on the o2 sensor wires, pooling, and then dripping onto the sensor itself
- CPV valve o-ring was replaced apparently 30k ago and doesn't show signs of leaking

From the top of the engine:
- Exhaust cam sensor on back of block looks to be covered in fresh oil
- If I reach my hand to the back of the motor where the half moons are, they have fresh oil coming from them and pooling off of them (creating the drip onto the wires I believe)
- Exhaust side of the valve cover + head have oil residue, but not fresh oil

My best guess is that the half moon section of the valve cover gasket has failed, and the oil is dripping from the back of the motor, all down the side of the head and block, and then hitting the o2 sensor. Perhaps it's so minimal that it's getting into the air, hitting the o2 sensor wires, pooling as a liquid and then getting on the o2 sensor to then burn (which is what I've been smelling sometimes when driving the car).

Am I right thinking this or is there something else I'm missing?

Thank you!

Jonathan

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UPDATE, SOLVED -
- Was the VCG (Had an Elring in there!)
- Installed OEM VCG as well as O-ring for Exhaust Cam sensor (Check my post Articles below for the parts I installed)
- NO SIGNS of leaking from CPV valve when I was under there and realized through documents that yes it was already replaced 30k ago
- So far no leaking or smell anymore

[Shonky]

Sounds about right. Get an inspection mirror and you should be able to see.

Use a genuine valve cover gasket IMO. I used an Elring one and it only lasted about a year. I tried a couple of times to reseat it etc with no luck.

Could also be the cam sensor seal. Cheap and easy to replace if you're doing the VCG.

[WestBankM4]

This same scenario literally just happened to me with leaks and drips on the exact same sensors, wires and locations. I had done my HG last year, put about 2,400 miles since then so I couldn't figure out why one day, at a red light I smelled burning oil. After parking my car in the garage, it would smell after I shut it down too so I decided to get underneath and inspect this weekend. Exact same leaks as you, same wires, and it dripped right on section 1 which was causing the smell. I traced the leak right to the valve cover gasket, passenger side rear corner, right by the exhaust CPS (which was also covered in oil).

I always order OEM BMW parts but this is the only time I ordered Elring from a local supplier, since I needed it ASAP. Couldn't figure out why this was happening since it was just replaced with minimal miles afterwards, go figure, Elring. Just go OEM from here on out but I'd say that's your culprit.

[ChapterM3]

Sounds about right. Get an inspection mirror and you should be able to see.

Use a genuine valve cover gasket IMO. I used an Elring one and it only lasted about a year. I tried a couple of times to reseat it etc with no luck.

Could also be the cam sensor seal. Cheap and easy to replace if you're doing the VCG.

Thanks for the reply! I'll make sure to get the OEM one, no chancing it again. I believe this one was an Elring one as well. Def on the cam seal as well, so much to do while that thing is off! Maybe I'll do my spark plugs a little early as well

[ChapterM3]

This same scenario literally just happened to me with leaks and drips on the exact same sensors, wires and locations. I had done my HG last year, put about 2,400 miles since then so I couldn't figure out why one day, at a red light I smelled burning oil. After parking my car in the garage, it would smell after I shut it down too so I decided to get underneath and inspect this weekend. Exact same leaks as you, same wires, and it dripped right on section 1 which was causing the smell. I traced the leak right to the valve cover gasket, passenger side rear corner, right by the exhaust CPS (which was also covered in oil).

I always order OEM BMW parts but this is the only time I ordered Elring from a local supplier, since I needed it ASAP. Couldn't figure out why this was happening since it was just replaced with minimal miles afterwards, go figure, Elring. Just go OEM from here on out but I'd say that's your culprit.

That's quite incredible that we had the exact same issue and diagnosed it this past weekend as well, even the leak location lined up! What are the odds haha. Alright well it seems like OEM is going to be my order, next weekend it goes in. Thanks for the reply!

[WestBankM4]

That's quite incredible that we had the exact same issue and diagnosed it this past weekend as well, even the leak location lined up! What are the odds haha. Alright well it seems like OEM is going to be my order, next weekend it goes in. Thanks for the reply!

I'm buying a lottery ticket tonight, what are the odds you get one too and we both win!?

[ChapterM3]

I'm buying a lottery ticket tonight, what are the odds you get one too and we both win!?

hahaha go for it!

[eacmen]

Genuine BMW valve cover gasket is worth the price. One of the few items I always buy Genuine.


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[cobra]

I also had this exact same issue this past month....

Guess what... Elring gasket. I contacted FCP and wanted to return it and pay extra for the Genuine gasket but they wouldn't let me, and said they have no record of high failure rate on this part. The forum says otherwise. And my stock gasket that went 100k miles with nary a leak also says otherwise. But I tried another one and will see how it does. It's not thaaaat bad of a job to replace it but not something I want to do again for a long time.

[Shonky]

What? FCP won't let you upgrade to genuine? I was intending to claim back on my Elring one and going genuine. I'm sure others have done similar for upgrades to genuine parts. Of course you only get refunded the amount of the original part.

[Vonbimmer]

Guys add me to the count on this one, I discovered the same leak and smell so I’ll be doing my VC gasket and cam sensor o-ring this weekend.

[cobra]

What? FCP won't let you upgrade to genuine? I was intending to claim back on my Elring one and going genuine. I'm sure others have done similar for upgrades to genuine parts. Of course you only get refunded the amount of the original part.

Yeah they pushed back on my request.

You bet if it leaks again I'm not putting another elring in there.

[ChapterM3]

Wow no kidding - where has everyone been experiencing their leak from? Same location of the half moons in the rear?

[ChapterM3]

Just put my order in at FCP - they have everything Genuine BMW, just not in a kit like the Elring kit. Here they all are, with part numbers and quantities if you guys need them! I'm doing my spark plugs at the same time about 6k early but might as well while I have everything open.

Also a note to grab the cam sensor o-ring while you're at it - it's the only time you can replace it and it's around $1 so you might as well if you've not done it before. I already bought one previously that's why it's not in my order here but here's the part number if you need it:

BMW Position Sensor O-Ring
VNE-104482

[Amos]

I had the same leak with a fresh Elring gasket a view years back, around the half moons and dripping on the exhaust. Replaced with OEM and no issues since.