[hkb84]

I changed all four spark plugs at 99K miles and noticed there's oil on the threads. I don't see any in the well or the base of the spark plugs. There's some crusty coatings near the nut area though. I googled and found there could be few causes below. I appreciate any comment or opinion on this issue. My car is not burning oil and I don't have any white smoke at the tailpipes. The old oil did smelled like gasoline every time I changed it.

Valve cover gasket - I replaced this at the same time as spark plugs.

Blown head gasket

Bad valve stem/guide seal

Damaged piston ring

 

[TalonTsi90]

Blown head gasket

Bad valve stem/guide seal

Damaged piston ring

Not remotely possible. It was the vc, period.

 

[tickerguy]

Yep.

Oil coming from the bottom (in the cylinder) will foul the insulator and is obvious. That was coming from the top (the well where the plug goes.)

 

[mitro6ual]

you did replace spark plug gaskets with VC, right?

 

[hkb84]

Thank you all! That makes me feel a lot better. I don't have the money or expertise to touch anything related to piston or valve stem seal. I replaced the valve cover gasket but didn't realized there are spark plug gaskets. This diagram below doesn't show that information. Does anyone know the part#?

 

[mitro6ual]

Thank you all! That makes me feel a lot better. I don't have the money or expertise to touch anything related to piston or valve stem seal. I replaced the valve cover gasket but didn't realized there are spark plug gaskets. This diagram below doesn't show that information. Does anyone know the part#?

View attachment 247035

They usually come with the VC gasket kit.
It's the rings in the center of the gasket in your image there.

 

[TalonTsi90]

It certainly does show them, 10-235.