1994 Chevy Silverado Truck / 5.7 L Engine with heater Problems/

Discussion in 'Chevy Truck Forum' started by mando1, Dec 17, 2012.

  1. mando1

    mando1 Full Member

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    I tried my heater for the first time on Saturday and all I get is cold air,no heat at all.The AC is working ok.I have a new 195 thermostat in it.Water level is ok with Antifreeze.I ran the motor for about 15 minutes and than touched the 2 heater hoses and the intake is hot but the outlet hose is warm.Could this be because of a bad heater core? A friend suggested that I may have a bad Blend door.I removed the glove box and was able to see the blend door actuator (I guess thats what its called) and when I move the temp control from C to H,I can see the little grey arm move back and forth.This would indicate that the Actuator is turning and thus closing and opening the blend door,right.The mode switch is working ok because I can get air from both top and bottom vents.What is the best way to troubleshoot this problem.Don't want to start replacing parts that I don't need to replace.I am new to this forum so I hope this post goes tru.Thanks for your help.
    Mando
     
  2. chevychase

    chevychase Semi-Admin
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    Sounds like a blocked heater core . Take both hoses loose get a water hose with some pressure try to unblock it.
    Maybe the temp actuator in the diagram . [​IMG] [​IMG]
     
  3. chevychase

    chevychase Semi-Admin
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  4. mando1

    mando1 Full Member

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    This info is very helpfull to me.I will remove the hoses tonight and force water in there to see if I can unplug whatever is in the way.Once I see that the water comes out ok and clear,I will than remove the temp.actuator to see If it looks ok.
    If the heater core is not plugged up,would it be a good idea to try a new Temp.Actuator?That would be in Diagram B.
    Thank you very much for your help.I really apreciate your help.Thanks also for the diagrams you posted.

    Mando
     
  5. leolkfrm

    leolkfrm Full Member

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    did anyone put a water shutoff valve on it for summer?
     
  6. chevychase

    chevychase Semi-Admin
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    Yes if core is not blocked likely suspect would be the b in diagram temp mode actuator.
     
  7. dirtrider73068

    dirtrider73068 Senior Moderator
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    Doing this being very careful don't need to turn the water on full blast, you could make it worse, if its a bad spot on the heater core and you force alot of water in it can make it leak.
     
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