S54 leak at back of head

[trigtm]

I am chasing down a small oil leak that I narrowed to the back of the head where both cam sensors are and also a few allen and freeze plugs are located. Anyone familiar with this kind of leak?

I've already changed out the valve cover gasket and confirmed it's sealing correctly. Also the CPV o-ring was replaced (though the leak is higher than that so I ruled it out anyway). Lastly I am changing the oil filter housing gasket as that's leaking also but on the other side of the motor. I did confirm some oil present using a mirror on the bottom of those allen plugs (red).

Not my pic, pulled from a recent fb post.

[Lukem3]

Thoes plugs highlighted all have orings or washers so it could be leaking from that. What's more likely tho is the valve cover is leaking at the half moon point. You're supposed to use some rtv along there according to bmw.

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[trigtm]

Thoes plugs highlighted all have orings or washers so it could be leaking from that. What's more likely tho is the valve cover is leaking at the half moon point. You're supposed to use some rtv along there according to bmw.

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From everything I've read about the VCG, it's RTV only at the front where the VANOS and the head meet. I guess I can take the VCG off again and reseat but am trying to figure it out first. Those allen plugs look like they have aluminum crush washers and if they have never been disturbed, I doubt they would just start leaking like if a rubber o-ring was perished.

[Cubieman]

From everything I've read about the VCG, it's RTV only at the front where the VANOS and the head meet. I guess I can take the VCG off again and reseat but am trying to figure it out first. Those allen plugs look like they have aluminum crush washers and if they have never been disturbed, I doubt they would just start leaking like if a rubber o-ring was perished.

I know how tight it is back there but you could get a rag with brake clean back there and wipe the oil away then take the vehicle for a drive and take corners easy as to not move oil dripping down to the left/right, then use a small mirror/strong LED flashlight to narrow down your search.

I would look with any and all tools available like a wifi/Bluetooth borescope before pulling the valve cover again which might not tell you much. If it's leaking from the half moons you should be able to identify that w/o pulling the cover I would think.

Did you use a genuine BMW valve cover gasket and spark plug seals?

[trigtm]

I know how tight it is back there but you could get a rag with brake clean back there and wipe the oil away then take the vehicle for a drive and take corners easy as to not move oil dripping down to the left/right, then use a small mirror/strong LED flashlight to narrow down your search.

I would look with any and all tools available like a wifi/Bluetooth borescope before pulling the valve cover again which might not tell you much. If it's leaking from the half moons you should be able to identify that w/o pulling the cover I would think.

Did you use a genuine BMW valve cover gasket and spark plug seals?

No, they were Reinz I think (I know...).

The oil drips all the way down to the weep hole between the engine and trans and then gathers on the belly pan. I must not have alot going on in my life right now to chase this small leak but I need to find it!

[Cubieman]

No, they were Reinz I think (I know...).

The oil drips all the way down to the weep hole between the engine and trans and then gathers on the belly pan. I must not have alot going on in my life right now to chase this small leak but I need to find it!

A small mirror on a stick and flashlight and I'll bet you can locate it with the cabin air housing removed. A borescope would be nice though.
Others may chime in but from what I understand you really only want a BMW VCG. I bought an Elring set and didn't use it after doing some reading about non-BMW vcg's being junk.
That being said the VCG I removed that the previous owner of my vehicle installed was a Victor Reinz and it sure didn't leak and no RTV on the half moons. I put RTV in the half moons and that was a dumb move as it will be very difficult to clean it out effectively without getting debris into the head. It really doesn't need any there imo.

[maupineda]

I went through 3 VCG (elRing) and only the OE item did it for me. No RTV needed

[Jickel180]

I was chasing an oil leak at the back of the engine for a long time. I replaced the CPV, oil return line, valve cover gasket, and cam position sensor o-ring. Turned out the oil return line from the valve cover had a gash in it (valve cover/head side of the banjo), and no new crush washer would fix it. I replaced that entire line, and I still had a leak. Ended up being the replacement valve cover gasket causing another leak. So the original leak was fixed from the new oil return line, but the next leak sprung from a non-oem valve cover gasket. When I received that gasket from ECS it was basically balled up and and didn't seat right. I'd double check your valve cover gasket.

[trigtm]

I might go with an OEM gasket but the one I have on there now was packaged well and flat on cardboard.

I’m going to replace both cam sensor o-rings and put it back together without touching the VCG and check again. If there is still a leak, I’ll replace the VCG at that time. Not much else to do and I really doubt it’s those Allen plugs or the head caps/freeze plugs (there was an m-coupe thread where one fell out but that’s not my problem after inspecting with a mirror).

I’ll report back.


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[SteelGreyM]

FWIW my super blown-between-all-cylinders head gasket caused my engine to have this exact same look. Looked like a head gasket leak. Not sure if that’s possible or whatnot just sharing my experience.

[BubbaTree]

I've replaced numerous VCGs on my car, and only once did I use a Reinz product. Only once did a VCG leak, and it was the Reinz. I always put a dab of rtv on the gasket half-moons before installation, and never had a problem except the Reinz.

[trigtm]

I replaced the o-ring on the exhaust cam sensor and that seems to have stopped the leak. I’ve only put about 25mi on it but I’m going to an auto-x tomorrow. I replaced the oil housing gasket too...and that was definitely blown. ECS sells a bit on one that I went with for longer life.


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[MathewM3]

I tried aftermarket vcg gaskets a couple of times, Reinz and something else that I don't remember the name of. Both times ended up with leaks. Use Oem and you will not have a problem.

[natty99]

The o-ring for the exhaust CPS is notorious for hardening and leaking over time. May be mistaken for a leaky VCG

[IMOLA3]

I am chasing down a small oil leak that I narrowed to the back of the head where both cam sensors are and also a few allen and freeze plugs are located. Anyone familiar with this kind of leak?

I've already changed out the valve cover gasket and confirmed it's sealing correctly. Also the CPV o-ring was replaced (though the leak is higher than that so I ruled it out anyway). Lastly I am changing the oil filter housing gasket as that's leaking also but on the other side of the motor. I did confirm some oil present using a mirror on the bottom of those allen plugs (red).

Not my pic, pulled from a recent fb post.

Does anyone know the hex size for these circled bolts? I have a leak coming from the passenger side one and am having a hard time getting anything back there without dropping it down into the engine. Going at it from underneath doesn't seem any better. Any tips are much appreciated.