I am doing a tune up on my car and noticed I have oil on my spark plugs. What should I do about it and what causes this to happen?
Oil on the spark plugs tells me there is an internal oil leak inside the engine. You could have a valve problem in the cylinder head which is leaking oil past the valve stem seals, or you could have a more serious problem like worn out piston rings.
You might want to try using a thicker weight of engine oil and or an oil additive like Engine Restore, to thicken and reduce your oil consumption. Also make sure the PCV (positive crankcase ventilation) system is working and replace the PCV valve if you have one.