So I woke up this morning and had a puddle of water under my truck> my firt thought was hose or something easy. after looking at it couldnt figure it out so i took it to the mechanic. think head gasket at that time. truck drove fine no problems. there is oil in the coolant (just a little). So mechanic say its the fuel cup in the head they sayen it was diesel in the coolant. they said i need new heads. I brought it home and checked the coolant i think its oil not fuel. i doesent smell like fuel. there is black on the resavor and little bit of white oily substance. what could be wrong with my truc. it an 04 f350 6.0 with juice with attitude.