Question about 2003 Ford Expedition
The heater in your car depends upon a flow of hot coolant going through the heater core in order to get hot air into the car. If the heater core is partially plugged, it will restrict the flow. If you have a head gasket that is putting exhaust into the cooling system, it will eventually get into the heater core. When this happens there is no coolant in the heater core to make the air warm. If the water pump vanes have corroded away the result will be very poor coolant circulation causing the heater to not blow hot air. If your car is equipped with a heater control valve that is not functioning properly, the coolant flow will be restricted. One or a combination of these factors is likely the culprit in your case.
if the car is not overheating, the thermostat is working fine.... replace or flush the heater core multiple times to try and eliminate sediment build-up.
Posted on Jan 13, 2009
The heater in your car depends upon a flow of hot water not just coolant going through the heater core in order to get hot air into the car. The issue could be but is not limited to the heater core being partially plugged. Your problem is most likely to be the heater control valve. There is a flap (vacuumed controlled) which closes off the heater core until you turn on the heat. Once the heat is turned on the heater control valve will open and allow the hot water from the engine to circulate into the heater core, the flap will also open and allow the air from the fan motor to blow across the heater core given you hot air but only if you have proper circulation to the heater core. If the HCV or the flap doesn't operate properly there will be no heat just cold air.
Posted on Jan 15, 2009
I would like to know if the heater valve fixed this problem?
Posted on Jan 12, 2010
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Posted on Jan 02, 2017
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