what is the metal "thermostat" like part called that goes on one of the heater hose? It has an upper and lower part with a vacuum port or something. mine is all rusty and i need a new one....the further i get, the further i go. All this started with changing my lower radiator hose.

Sounds like a water valve for a car with air conditioning. It's used to shut of the flow of hot water through the heater core while the a/c is operating. If your a/c is dismantled you can bypass the valve and plug the vacuum hose.

it was AC, however it has been removed.