[Efthreeoh]

Originally Posted by asiflicious

A bit off topic, but how serious is a VCG leak? When I was getting my spark plugs and coils replaced due to some misfires at cold starts my buddy discovered that three of my spark plugs were soaked in oil. He said i have a VCG leak and he tightened it a tiny bit to slow it down a little. He said it's a small leak and that I should get it fixed soon but not necessarily right away. That was a couple months ago and the car is driving fine. Should I go ahead and jump on it now or am I fine waiting a while more?

No one answered you since we got wrapped around the axle about rusty steel parts. I'll give it a shot. Now this is based on my experience with owning a Z3 for 20 years so take it with a grain of salt . On my wife's Z3, which has an M44 4-cylinder and for some reason leaks from the central donut rings that are part of the VCG set of the M44 (which has an aluminum valve cover). The engine has had enough oil in the spark plug wells that I needed to remove the liquid prior to replacing the plugs. It was enough liquid that it would have drained into the cylinders and the plug wells are not as tightly sealed as the N52 in the E90, so I was concerned about dirt being in the oil sitting around the plugs. I would imagine that the plug wells could fill up with enough oil to possibly short the coil to the sidewalls of a '06 N52 with a magnesium valve cover. The magnesium valve cover is electrically separated from the aluminum head since the two metals can chemically react (galvanic reaction) with each other. The '07 and up N52s have a plastic valve cover, so shorting is not an issue. Plus it would be rare anyway because the coil seals really well to the plug body.

As with the Z3, I think the only real issue with leaking oil into the spark plug well is it is a nuance most of anything and needs to be sucked out of the well prior to spark plug removal. Enough oil in the well would make for a burned oil smell. Would it ever cause a breakdown or fire? I doubt it.