Dodge Repair: oil leak in cylinder

Question
04 caravan 120,000 miles has oil on spark plug tip in cylinder 3.8 engine. what are the possible causes.

Answer
Hi Don,
It could be due to oil leaking around one of the valve stems, or to worn piston rings, or to a head gasket leak next to that cylinder. The first thing to check would be the compression of that cylinder and compare it to another. It should be around 100 psi at least. Are you also loosing coolant (excessive white smoke from the tailpipe when starting from cold)? If so that would point to a head gasket leak. Otherwise I would suspect oil leaking around a valve stem or the piston rings.
You can check the rings by adding a teaspoon of oil to the cylinder and then rechecking the compression. If it goes up noticeably that would suggest bad rings. Otherwise, then valve stem seal would be the likely cause.

Roland