Im leaking coolant out where the heater hose exits the themostat housing.There is some kind of plastic bushing in there that has gone bad.What is this plastic thing called and where can i find one? Also what is the proper way to remove and replace it?

3/4" barb x3/4" NPT will replace it better than another quick connect.

Mine was made with pot metal and it disintegrated. They had to chisel it out. They said this happens all the time. They seemed experienced in this fix, as opposed to taking the thermostat housing off.