2004 Ford Mustang Heater working partime

2004 FORD MUSTANG
60,000 MILES • 6 CYL • 2WD • AUTOMATIC
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HARRYRTAYLOR
  • MEMBER
  • 1 POST
The Heater in my car doesn't work like it is suppose to. I checked the coolant level and it was a little low but after filling it up and driving the car, the temperature gage was at the usual temperature but the heater still blew out cold air. Usually it will finally start working okay but doesn't always blow out hot air like it should.
Jan 2, 2010 at 10:10 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.
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MERLIN2021
  • CAR REPAIR CONTRIBUTOR
  • 17,250 POSTS
Heater Core — Plugged

WARNING: The heater core inlet hose will become too hot to handle if the system is working correctly.

Check to see that the engine coolant is at the correct level.
Start the engine and turn on the heater.
When the engine coolant reaches operating temperature, feel the heater core inlet and outlet hose to see if they are hot.
If the inlet hose is not hot:

the thermostat is not working correctly.
If the outlet hose is not hot:

the heater core may have an air pocket.
the heater core may be restricted or plugged.
If both are hot, the temperature blend door in the heater plenum may be broken or stuck...
Jan 2, 2010 at 10:55 AM
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