heater not heating
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Junior Member
Joined: Jan 2011
Posts: 56
From: Houston
heater not heating
I'm having trouble trying to figure out what could make my heater stop working. I'm getting various theories from past posts. Bear with me here:
Last year in one of our coldest winters yet, the heater was working fine, blowing really hot air. Water pump was also replaced that same winter. This summer was one of the hottest and driest, and although it would take a while for the car to cool (which is understandable when outside temps are 100+ and the car has been sitting in a shade-less lot and the fan has only four speeds at 65), it would get comfortable after driving for about 20 min.
Now the temps are cooling down and the heater isn't blowing hot anymore. No clue what happened. I have automatic climate control. I have turned the temp up to 80 and my hands are still numb and cold! I do know that whenever there is a little humidity outside, my windshield and rear window fog up and I have to deal with that, which is aggravating. I don't see any leaks (although I park my car on the grass so hard to tell :/) and the carpets aren't wet. I know my mom's car, a 2007 Mercury Milan with auto climate control, had a similar problem last year except it was reverse with the air not getting cool; turned out to be some kind of temperature sensor/thermostat. Could that be my issue?
Last year in one of our coldest winters yet, the heater was working fine, blowing really hot air. Water pump was also replaced that same winter. This summer was one of the hottest and driest, and although it would take a while for the car to cool (which is understandable when outside temps are 100+ and the car has been sitting in a shade-less lot and the fan has only four speeds at 65), it would get comfortable after driving for about 20 min.
Now the temps are cooling down and the heater isn't blowing hot anymore. No clue what happened. I have automatic climate control. I have turned the temp up to 80 and my hands are still numb and cold! I do know that whenever there is a little humidity outside, my windshield and rear window fog up and I have to deal with that, which is aggravating. I don't see any leaks (although I park my car on the grass so hard to tell :/) and the carpets aren't wet. I know my mom's car, a 2007 Mercury Milan with auto climate control, had a similar problem last year except it was reverse with the air not getting cool; turned out to be some kind of temperature sensor/thermostat. Could that be my issue?
Last edited by StartaFire89; Oct 31, 2011 at 07:12 AM. Reason: dumb smiley
Junior Member
Joined: Jan 2011
Posts: 34
From: Hoffman Estates, IL
sounds like your thermostat is stuck in open position. Thermostat starts at close position and only opens after proper engine temperature is reached. When thermostat is stuck open, it will open and circulate the coolant even before the operating temperature. it will take hours to heat up the coolant to the proper temperature.
Senior Member
Joined: Nov 2010
Posts: 400
From: Powder Springs, GA
I'm having trouble trying to figure out what could make my heater stop working. I'm getting various theories from past posts. Bear with me here:
Last year in one of our coldest winters yet, the heater was working fine, blowing really hot air. Water pump was also replaced that same winter. This summer was one of the hottest and driest, and although it would take a while for the car to cool (which is understandable when outside temps are 100+ and the car has been sitting in a shade-less lot and the fan has only four speeds at 65), it would get comfortable after driving for about 20 min.
Now the temps are cooling down and the heater isn't blowing hot anymore. No clue what happened. I have automatic climate control. I have turned the temp up to 80 and my hands are still numb and cold! I do know that whenever there is a little humidity outside, my windshield and rear window fog up and I have to deal with that, which is aggravating. I don't see any leaks (although I park my car on the grass so hard to tell :/) and the carpets aren't wet. I know my mom's car, a 2007 Mercury Milan with auto climate control, had a similar problem last year except it was reverse with the air not getting cool; turned out to be some kind of temperature sensor/thermostat. Could that be my issue?
Last year in one of our coldest winters yet, the heater was working fine, blowing really hot air. Water pump was also replaced that same winter. This summer was one of the hottest and driest, and although it would take a while for the car to cool (which is understandable when outside temps are 100+ and the car has been sitting in a shade-less lot and the fan has only four speeds at 65), it would get comfortable after driving for about 20 min.
Now the temps are cooling down and the heater isn't blowing hot anymore. No clue what happened. I have automatic climate control. I have turned the temp up to 80 and my hands are still numb and cold! I do know that whenever there is a little humidity outside, my windshield and rear window fog up and I have to deal with that, which is aggravating. I don't see any leaks (although I park my car on the grass so hard to tell :/) and the carpets aren't wet. I know my mom's car, a 2007 Mercury Milan with auto climate control, had a similar problem last year except it was reverse with the air not getting cool; turned out to be some kind of temperature sensor/thermostat. Could that be my issue?
- Does temp guage get up to normal temp fairly quickly? Then is it stable? If it does/is, then thermostat is probably good.
- Do both heater hoses get hot after you have heat on full for awhile? I neither get hot, lack of coolant or thermostat. If only one gets hot, probably blockage in heater core or problem with valving.
- Are you loosing any coolant? Check both overflow tank and radiator itself. I had an overflow issue and radiator almost dried up w/o me knowing because overflow tank level stayed OK. Lack of heat is what finally tipped me to problem.
- When windows fog up, is there any antifreeze smell? If there is, you could have leak in heater core.
- Run the FSM diagnosic process on the automatic climate control system to test sensors, etc.
Good luck!!
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