1980 cutlass overheating after 20 minutes?

Question

my brother bought a car its a 1980 cutlass recently i have replace the alternator,starter,fix the radiator,valve cover gaskets did the tune up but now the car its overheating i just change the thermostat cus the one its had was bad like rusted out well the only thing that could be will be a bad water pump right? but i need more info on was else can cause overheating before putting more money on that car

Answer 1

What motor does it have? Did you check the new Thermostat before installing it? Just place it in hot water and make sure it opens. Even new ones are sometimes bad. Did it overheat before you changed it? When you first start it leave the radiator cap of and if it has air bubble coming up in the radiator you have a blown head gasket. If all these things are ok then I would check the water pump.