What causes a Ford Windstar to all of a sudden blow cold air instead of warm?

Answer 1

AnswerIf you haven't had any work done relating to anti-freeze/engine coolant - the next most likely cause of this type of problem in a Windstar is the temperature blend door actuator motor. Extremely common failure item and easy to fix and not too terribly expensive.

See "Related Questions" below for more trouble-shooting/diagnostic and repair information
Answer

If you have the heater on and the fan is blowing warm or hot air and then changes to cold, you possibly have air in the circulation lines from the radiator to the heater core. As the water pumps pumps the water through then engine and then heats it up it goes to your heater core under your dash to provide you with heat. If there are air gaps in the system, the water pump will push the water through and then the air trapped and you will end up with cold or cool air. I suggest you check your antifreeze level WHEN IT'S COLD and see if you are low. If so, add antifreeze and run the engine at idle to get the antifreeze to circulate through the system leaving the radiator cap off while you are doing this. Hopefully as the water gets circulated around the air will come to the top of the radiaotr and escape, add more antifreeze and top off your radiator. Any excess fluid should go to your overflow tank. Some engines requires you open certain passages to release the trapped air but you could try this first

See "Related Questions" below for more ideas on what could cause this problem