There is oil in the recess of the W203 C180 spark plug.

[TDudette]

I discovered that all four of the spark plug recesses were filled with old engine oil after yesterday's oil and filter change. Unexpectedly, the coil and plugs were functioning well (and continue to do so) and there was no engine misfire; I suppose it had to have been there for some time.

Cleaned it all up & picking up a replacement cam cover gasket set today. I really hope the cover isn't cracked and that's the only thing it is.


Are there any other common reasons for this problem?

[Geek2232]

Because they squeeze each round gasket around each plug, I would assume that whoever changed the plugs last didn't torque the spark plug nuts down correctly at 11nm (I think). The oil will seep past the gaskets and pool around the plugs if they aren't snug enough.

[TDudette]

Fitted a new gasket to the cover and spark surround. Those wheels on this engine aren't circular! The worn-out rubber felt a little compressed and worn out!

The acoustic cover is still removed, allowing me to inspect the coils for any additional leakage. All right, tightened down properly.


While I am waiting for new spark plugs at my son's place, I must say that the current plugs are still in quite decent condition. His employment with Niterra (formerly NGK) is fairly practical.

[Geek2232]

As far as I'm aware, there is no English word that adequately describes the shape of the spark plug recess gaskets, therefore I used the word "round" to describe them. Well done!

[CyberNinja]

In that circumstance, I'd expect to see a lot of combustion gas exiting. Perhaps the oil could even be redirected?

Probably a cam cover that's leaking.

[Geek2232]

It's a spark plug gaske that's leaking from the cam cover.

[Geek2232]

[Geek2232]

😉