Overheating issue/blowing coolant..WTF????

I’m stumped… It’s blowing coolant out of the overflow even before it gets hot, no temp light comes on until it blows all the coolant out.
It’s building up a lot of pressure in the radiator and blowing coolant.
I’ve burped this thing several times through the would be t-stat housing until I get coolant… fill the Rad and do it again,, constantly keeping the rad full. No matter what, it blows coolant.
The fan is wired through a switch and runs good, pulls good air, Rad and oil cooler is clean/mud free.
Anyone have any clue??? I need help