sootman73, it's best to remove the thermostat when refilling the cooling system to ensure the engine block is filled with coolant. When I had the upper radiator connection break off I simply secured the upper radiator hose to the remaining stub and added coolant to the expansion tank ... no need to remove the thermostat. Until you replace the radiator you may want to try running the engine with the expansion tank cap loose so the cooling system doesn't build-up pressure and cause the upper radiator hose to blow off.

I recommend replacing the radiator immediately. Shop around for the best price on a new Behr radiator. The newer Behr radiators have a metal-reinforced upper hose connector.

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Fred Hoelzle