I have a 1994 Ford Mustang GT 5.0. I installed a new water pump and thermostat cause the water pump was leaking. It started to over heat a week later so thats when i just changed the thermostat. There are no leaks I beleive I have all the air out of the system. Im not sure what else it can be besides the radiator now. All of these parts are original. I have 109*** miles on the car. I just got the car not too long ago. It blows cold air when its turned on and hot air when its on. Any ideas?