Here is a pic. White/gray goo coming from the radiator cap. I checked the oil cap and the stick and everything looks fine there.
2004 Ford f-250 diesel 6.0

 

Welcome to the site..

Any power building equipment installed, chips, flash tuned or? Miles on the truck? Prior repairs, mods etc.

Couple things, failing head gasket/s can allow compression/combustion pressures into the the cooling system and cause a coolant blow out through the degas bottle.

If the engine oil cooler is coolant flow restricted or cut off, can raise engine oil temps at the least, and can then affect coolant flow to the EGR cooler and can cause it to overheat and boil the coolant within causing the high pressure steam/coolant back out the degas, or crack, and may allow engine exhaust pressures to enter the cooling system.

Generally early on if EGR cooler, most notice the coolant level dropping with no real indication of a leak or may show up as degas white tracking, later on or when the failure increases or cracks you may notice steam out the tail pipe ( could be caused from head gasket as well but EGR cooler tends to go more un noticed )

EGR flow helps to lower combustion heat, peak temps and pressures. When combustion pressure/temps and coolant temps rise can help to cause head gasket failures.

 

Welcome to the forum!... Unfortunately, you will probably need an EGR cooler, oil cooler, full engine flush, new hoses, and maybe a new radiator. Do not drive that thing anymore, have it towed to your nearest Ford dealer. I am sorry to see that man, it looks like a nightmare.