Top Radiator Hose Collapses

What coolant? Thermostat and size....
The Orange Stuff 50/50 Mixture
185 Thermostat
Mopar 360 Motor
The Canister is not Vented, Never was it has a hose from the top of the Radiator to the chrome catch can, its a sealed unit. It seems like it didn't do this last Summer, just this summer, nothing changed to the system flushed out the old stuff and filled with new stuff. Well what's next....
I don't mind replacing Stat but I hate just throwing parts at it....

Please help....

Oh the over flow tub is not plugged because sometimes there is some coolant in the bottle...
There is a **** pit value on the bottom that I can release antifreeze.

And how can the over flow bottle need to be vented, its a sealed unit form Summit one inlet on top and nothing else except to drawn from the bottom.