Trouble in cooling system

Hello all, have an issue with my trucks cooling system.

It's a 2013 Cascadia DD15.
Last 8 of VIN: DSBZ6783
720k miles

It looks like a pressure buildup in the cooling system. From the moment I start it up there is a lot coolant rushing in from the egr valve into the reservoir.

With the old radiator cap on, coolant will gradually overflow the tank and leak out the top.

I replaced the cap with a new one and the level stays even in the tank, however hoses are starting to bust when the new cap is on.

In the lead up to this, I've had the egr cooler replaced and had blown head gasket. Did an inframe, the pressure issue persists.

Using an exhaust gas test kit, it doesn't look like any gases are getting into the coolant.

At this point I'm tapped out and am having to wait on going back to a mechanic. Just trying to get some ideas to look at.

Any suggestions would be appreciated.

 

Replaced it just before everything else started, however, doesn't seem to be any difference if the compressor is running or not

 

I have recently had ours replaced as well, however, it was prior to all the other stuff that went down. The overflow portion is filling up, so, that could mean it is broken again. Just feels like whack a mole at this point without finding a cause.

 

Well, I brought the truck to the shop today. Talking through with the mechanic, their first inclination went to the air compressor, but they're gonna dig in to rule out all possibilities. We'll see!