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heat

Discussion in 'Ford Trucks' started by dany, Dec 24, 2001.

  1. dany

    dany Member
    Messages: 89

    The heat in my 75 f-250 went south. The blower and everthing else is working fine could it be the thermostate or the heater core. It is blowing cold air all the time at full operating tempature. What is the average cost of such parts? What else could be wrong? If it matters the motor is a 390.

    thanks and happ holidays
     
  2. DaveK

    DaveK Senior Member
    Messages: 420

    Could be a few different things. Assuming that you have checked the obvious, like low coolant level.

    Feel both heater hoses going to the heater core. If both or one is cold the heater core is probably plugged. Sometimes swapping the heater hoses will help unplug it by reversing the coolant flow. If this solves it, a flush and fill would be a great idea.

    If both hoses are warm, it could be the temperature control in the cab.
     
  3. dany

    dany Member
    Messages: 89

    If the heater core is plugged would it be alright to drive it 10 to 15 minutes to be sure to get any junk out or would doing it that long bother the core? The tempature control would be were i select hot from cold and defrost from heat? Thanks
     
  4. DaveK

    DaveK Senior Member
    Messages: 420

    Driving it 10 - 15 minutes would not hurt it as long as you are sure the system is full of coolant and that it isn't froze (ice due to temperature)



    Yes. I'me not sure if yours is cable or vacuum operated, but that is a possibility.

    Start it and let it reach operating temp, then feel the heater hoses. That will tell you right there what it is. (see above)

    Merry Christmas.
     
  5. dany

    dany Member
    Messages: 89

    the controls are operated by cables.
     
  6. dany

    dany Member
    Messages: 89

    Since my heat is not working should this also be a sign to change my thermostate?If so what should i replace it with any certain brand or type? What are the exact purpose of one?
     
  7. DaveK

    DaveK Senior Member
    Messages: 420

    THe thermostat allows the water to circulate through the engine and heater core only when cold (not the radiator). This is so you get warm air sooner.

    If the thermostat is stuck open, it will take much longer to get warm air inside the car. But eventually it would get warm.

    Go to any auto parts store and they can sell you the thermostat you need.
     
  8. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    dany,in your first post,you sais even at full operating temp,so i thought you had a guage,if its running 190-200,you should have heat.Does it use a hot water control valve? if so,make sure its opening,maybe the cable is broke or the valve is broke.If it uses air doors,try to find out if the dorr is adjusted right,and is colsing off all the cold air.You can back flush the heater core,but if its plugged up,you should replace it,and flush the colling system.