Originally Posted by I Shine

When I check the coolant level in the radiator I can see a little bit of oil floating on top of the coolant. After further inspection the under side of the radiator cap has a thick black grease film. The inside of the filler neck has this same film. There is no signs of water in the oil and the engine runs strong. The engine appears to have been well taken care of. I'm thinking maybe it previously had a blown head gasket and the radiator was not properly flushed. Can this grease be flushed out of the radiator ? Should I just take the radiator out, fill it full of a de-greaser, and give a good flush. Or maybe just buy a new radiator.