Chasing oil leak on s54

[InterlagosMC]

I’ve been chasing an oil leak on my coupe for the last year and still have a slight leak but can’t figure it out. It’s not from the valve cover gasket, vanos gasket, chain tensioner, cam position sensors or any of the high pressure lines as these have all been replaced recently and are all dry. The underside of the head gasket lip along the exhaust side of the engine is a little wet and then tracks down the block towards the front by the chain tensioner but I can’t find where the leak is coming from with visual inspection. I might replace the CPV again as this was done about 5 years ago but that is lower than the leak. The cylinder head is completely dry so I’m wondering if it’s the head gasket that’s letting oil out although I can’t find any information on this for s54 engines.

 

[-Tom-]

How long ago was the chain tensioner replaced? Mine has gone / leaked twice in ownership (10 years or so)

 

[InterlagosMC]

How long ago was the chain tensioner replaced? Mine has gone / leaked twice in ownership (10 years or so)

I put a new one in 2 years ago with the vanos rebuild and can confirm that is completely dry now but still can’t figure it out, seen a thread that someone had a loose bolt that holds the chain guide behind the thermostat so will have a look at that but I don’t want to remove the thermostat and drain coolant if it’s dry in that area

 

[AndyBeech]

How long ago was the chain tensioner replaced? Mine has gone / leaked twice in ownership (10 years or so)

I put a new one in 2 years ago with the vanos rebuild and can confirm that is completely dry now but still can’t figure it out, seen a thread that someone had a loose bolt that holds the chain guide behind the thermostat so will have a look at that but I don’t want to remove the thermostat and drain coolant if it’s dry in that area

I did it on mine, didn't have to drain coolant IIRC, just needed bleeding I believe. Worth a look (you should be able to see if its wet without removing too much, though it's tight access round there).
I got bored chasing oil leaks, fixed one and another one seemed to pop up before too long so I just live with the weepy one I have at the moment, treat it like a feature :lol: Resigned myself to head gasket replacement time to fix whatever it is.