help identify oil leak near valve cover

[usdmej]

hoping to get some help on figuring out a couple of potential oil leaks on my car
for picture location reference, the coolant reservoir is on the left, and the valve cover is on the right. picture taken from the front of the engine towards the rear

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noticed a light pool of oil on my exhaust heat shield on the center of the engine (3 arrows)

and also a plug (cam sensor?) that's saturated in oil towards the rear of the engine (single arrow)

not sure if this is indicative of a failing valve cover gasket or what, any input is appreciated!

[racinghart]

I would replace the vcg and check the o-ring on the camshaft sensor as well while you’re at it.

[eacmen]

That exhaust camshaft sensor o ring can leak more oil than you would think it would.

Pretty easy fix but requires some flexible hands.


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[TexaZ3]

Looks like camshaft sensor o-ring to me as well.

[CrookedCommie]

I can't get the new exhaust cam shaft sensor to stop leaking, been through two o-rings now. Any tricks? Thinking I need to put the o-ring into the head first, then the sensor. I have a new bolt with blue loctite, but it still leaked.

[jbfrancis3]

Agree with all of the above - I had the same issue which was cured with camshaft sensor oring replacement.

[eacmen]

I can't get the new exhaust cam shaft sensor to stop leaking, been through two o-rings now. Any tricks? Thinking I need to put the o-ring into the head first, then the sensor. I have a new bolt with blue loctite, but it still leaked.

Thats odd. I just replaced it and it stopped leaking right away. You should clean out the head surface with some red 3M pad or similar. Apply clean engine oil to the O-Ring and re-install.

Maybe the sensor itself is aftermarket and Doesnt seal well with the O-Ring?


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[eacmen]

Decent video on how to do it: https://youtu.be/2uHOcSLNLOY

I did it with the valve cover off though during Valve adjustment so it was much easier.


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[CrookedCommie]

Thats odd. I just replaced it and it stopped leaking right away. You should clean out the head surface with some red 3M pad or similar. Apply clean engine oil to the O-Ring and re-install.

Maybe the sensor itself is aftermarket and Doesnt seal well with the O-Ring?


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That's what I thought, or the o-ring was cheap or I pinched it. I verified the sensor is from FCP euro and the bmw logo was cut off of it, so it should be the same as stock. Will try again!

[eacmen]

That's what I thought, or the o-ring was cheap or I pinched it. I verified the sensor is from FCP euro and the bmw logo was cut off of it, so it should be the same as stock. Will try again!

Also check VCG above the sensor.


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[chicane]

I can't get the new exhaust cam shaft sensor to stop leaking, been through two o-rings now. Any tricks? Thinking I need to put the o-ring into the head first, then the sensor. I have a new bolt with blue loctite, but it still leaked.

Trick #1 you could go with a non-stock O-ring with a ever slightly larger diameter (CS not OD) to account for any wear. Trick #2, which is a hack, but I had to on an E46 sedan coolant pipe that would not stop leaking even though I replaced with OE O-rings, an ultra fine layer of RTV on the O-ring itself.

[CrookedCommie]

Trick #1 you could go with a non-stock O-ring with a ever slightly larger diameter (CS not OD) to account for any wear. Trick #2, which is a hack, but I had to on an E46 sedan coolant pipe that would not stop leaking even though I replaced with OE O-rings, an ultra fine layer of RTV on the O-ring itself.

Perfect, this is next if it leaks again. Thanks!

[DanAvoN7]

While there is oil on the exhaust camshaft position sensor it doesn't look like that's the culprit. Oil flows from front to back and it happens to be ending up there before heading down the backside of the engine.

If you look at the ground for the ignition harness there is a good amount of oil residue on it. You likely do have a main valve cover gasket leak and or from one of the the valve cover rubber grommets and then the oil is running back along that ridge. If you remove the plastic "M" beauty cover you can get a better view of everything and see if it's coming from the perimeter grommets or the actual main valve cover itself. Cheaper Elring / Victor Reinz brand gasket sets are prone to leak and or leaks caused from improper installation.

[mrgizmo04]

Came here to suggest what Dan mentioned - remove the beauty cover and check to make sure the grommets or the spark plug tube seals are not the culprit. They were on mine after a hot track day.

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[usdmej]

checking back into this thread after finally getting around to fixing the leak. big thanks to DanAvoN7 and mrgizmo04 as they were right on the money about the valve cover gasket as well as a couple of valve cover grommets that had prematurely failed.

fwiw the gasket kit that was on there was Victor Reinz replaced ~2k miles ago