Anybody heard of head gaskets, block crack etc that have happend with these engisne that cause coolant in oil. I just had my truck worked on and when I changed the oil today it was greenish in color. I suspect it is from the blacklight dye added to detect an oil leak at the Cummins shop but figured I would ask since I have previosly noticed white build up on my oil cap. Anybody else have slight oil vapor build-up on fill cap?