Oil on spark plug

[bizz]

Hi all,
I pulled my #6 plug (closest to firewall) yesterday, and noticed oil on the thread - accumulating near the washer.

Here's a pic, sorry it's not the best.



Any idea on what the cause of this is? I have just replaced the valve cover seal & there seem to be no leaks.. A crack in the head possibly?

Thanks,
Ben

[Mike W.]

Don't worry about a cracked head, that's not where they crack or how they crack, at least for M10 and M30 engines, I can't say for M20s. But the electrode looks dry so I'd say you're in good shape.

[bizz]

Thanks Mike, I will pull the plug again tonight to check for oil.

Any ideas where the oil would come from?

[Mike W.]

I'd almost guess a spill. Those spark plug wells are pretty deep, if something gets in there it's not coming out easily.