Originally posted by Bradness:
Oil can come from bad valve stem seals too.....


Not in the spark plug well!

That is "outside" the engine altogether.

The only way for oil to accumulate there is from a leaky cam cover gasket.

A leaky valve stem seal leaks top cylinder oil onto the base of the valve and into the combustion chamber. It is there burned off at startup resulting is a nice blue cloud out the tail pipe.
Extremely bad valve stem seals (or bad/missing seals) can leak under engine breaking and simple idling even.

Nothing could leak into the spark plug well without compromising the cylinder entirely (I.E. you would lose compression!) except for the afore mentioned gasket.

2000 SVT #674 13.47 @ 102 - All Motor! It was not broke; Yet I fixed it anyway.