 Own two fords . A 6.0 and 6.4 liter. 117000 miles on 6 liter,4 engines and nearly 26000$ spent.  6.4 liter 153000 miles, the engine grenaded itself and is junk. No rebuilding a 6.4... Nice. 20000$ plus to replace it. Go look at the auto auctions in the mechaniclaly totaled vehicle section, it is full of hyundias and ford diesels. There is a reson for this