Z4 2.5 oil leaking onto exhaust

G

George74

New member
I had smoke from oil dripping onto the exhaust - passenger side - rear of engine. I also was getting a few drops on the garage floor. The leak appeared to be coming from under the aluminum heat shield that is below the valve cover and above the exhaust manifolds. The rear heat shield where the leak is, is also loose. Anyways due to so many people having valve cover gasket issues, I figured it would be $50 well spent so I replaced the valve cover gasket and rubber grommets yesterday. The job went well and I had no issues. This morning I took the car for a 5 minute drive and when I looked under the hood, I had the smoke just like before. There are no leaks around the valve cover but there is a leak at the bottom edge of the heat shield mentioned above. So I have ruled out the valve cover for sure.

So now I am wondering what is going on. Can oil leak out of the exhaust manifold? Any help would be appreciated. Thanks.
 
Same here, the oil will have run all over the side of the engine, got stuck in the gaps ect, give it a good clean with some brake cleaner, and take it for a run, it will go eventually.
 
Did you put the small blobs of sealant on corners of the half cylinder corners and where the Vanos is bolted to the head.... The TIS calls for the addition of small amounts of sealant at these points. The small blob is required on the join of the Vanos to head to seal the joint which is right angles to the line of the gasket. It appears to be a common point for oil leaks. You can't see the leak unless you have one of those small inspection mirrors. If the leak/ drip is large enough, the oil will travel down on the underside of the valve cover/meets head... Until it drips down on that aluminum shield at some point. That's where my leak was from.... Front lower Vanos joint (passenger side).


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Yes, I put the sealant in the half rounds. The valve cover is not leaking at all. The leak is under the heat shields by the exhaust manifold which I cannot see but I can feel the oil from that area.
 
Did you also smear a small blob on the joint where the VANOS bolts on to the valve head... When I was investigating the cause of my leak I found that it was from this joint my oil was leaking from. The oil would travel down the underside of the valve block until it decided to drip down on the aluminum splash guard over the exhaust manifold. If you use one of the small inspection mirrors with a LED built in you might be able to trace where the leak is originating from. Clean the underside of the valve cover/block and then run the engine for a bit to see the oil. Brake cleaner is good for cleaning up the area. Also spray where the VANOS bolts on... Especially on the low side.
 
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