Oil in spark plug chamber

[abscate]

The oring failure mode is very rare. Much more likely the oil is seeping from the PCV or oil cap, especially if Is number 3 cylinder

[scot850]

A little confused on this. Cylinder #1 is the one closest to the passenger side fender and the end of the engine with the cam belt and crank pulley.

#5 is the one nearest the air box.

Assuming you do mean the #1 cylinder it is the most common along with #2 and even #3. if the oil filler seal fails. The seal should be soft and the oil cap have a little resistance when turning.

The other possibility for that area is a leaky or split in the PCV hose that runs to the top of the engine and runs past the oil filler cap.

Welcome to the forum and here's hoping it is a simple fix.

Neil.