Head Gasket or EGR Cooler?

[Big 04 F250]

I have a 04 F250 with the 6.0 and when I get on it or tow a trailer it pukes coolant out of the degas bottle. I took it to the ford house and they said I needed a new degas bottle and cap. I brought the truck home and did a pressure check on my degas bottle and cap. The degas bottle held pressure up to 17lbs for 10 mins and the cap failed so I bought a new cap and still have the same problem. I am a diesel mechanic but I am new to the 6.0 engine. I have read alot about the head gasket signs and the EGR cooler signs and alot ot them are the same. So what do I have Head gaskets or EGR cooler? I am stumped! I dont want to pull the engine apart if I am just having a egr cooler problem. I plan on bullet proofing the engine with arp studs and all of the bullet proof stuf when the time comes. Thanks for the help.

[AlwaysBroke]

i would pull the egr valve and see if it has been getting moisture in there

[waterfowl1989]

sounds like the coolant is flash boiling. i would first check and see if oil cooler is clogged! what coolant are u currently running in truck?