Originally Posted by Snuggyworm

before i go towards the blown head gaskets, i'd check the egr cooler and oil cooler first. usually if one goes, then its time to change the other as well. common probs of the 6.0

its a common misconception when everyone defaults to the head gaskets at first opportunity. remember the white smoke? usually means u got coolant in the egr valve. might be the egr cooler failing. also, check the egr valve as well. if the spring is worn out, it might be more economical for u to replace the entire egr valve as well. safety first.