I have a 2005 F350 with a 6.0 diesel, started smokin alot of white smoke,lost all it's coolant and has lots of oil in muffler.theres no water in oil but can't keep coolant in it. Could this be a head gasket or what could it be?

 

either head gasket or EGR cooler, ( I suspect EGR cooler, having read the stories on the forum). Get out your wallet and bring a good supply of vasoline to the dealership......

 

https://www.ford-trucks.com/forums/1...ite-smoke.html
https://www.ford-trucks.com/forums/904996-smokin.html