Don't be ordering head gaskets just on that word. There are several issues which can cause what your explaining. May also be a warn water pump impellar. Do a coolant test to see if there is CO in the coolant and also do a pressure check of the cooling system. Blocktest Kits for CO are available online. See the following video and you don't need the EDAS installed.
HEAD GASKET TEST for 6.0 POWERSTROKE - YouTube