[DavesRide]

FYI. There is a service bulletin for this same condition. Yes, all of the causes posted are reasons. The bulletin is about a crack in the head on a certain casting. You have to remove the valve covers and look at the casting #'s. You can also see the clean spot where coolant slowing runs down into the oil where it evaporates. I have seen a couple and it was built in on some of these trucks. It really doesn't hurt anything other than waste coolant and worry the owner with the light on.