Do you smell antifreeze in the interior ?
Chk your heater core ,pass side ,lift the carpet look for wetness.
Look for bubbles in the coolant if you think headgasket.
If your losing that much ,you'll find it!

Rich


02 F250 4x4 SC 5.4v8 6spd 3.73ls Trueblue/Silver and Chrome Nerfs

"All Levers"