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Lack of heat

Discussion in 'The Garage' started by 90gmcburb, Dec 14, 2004.

  1. 90gmcburb

    90gmcburb Registered Member

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    I just bought a 90 gmc suburban w/the 350. Since it is 20 deg here the heat does not come out real warm. What problems can I look for to get the heat back working correctly? Also what should be the normal operating temp on the vehicle? Thank you.
     
  2. Poohbair

    Poohbair 1/2 ton status

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    Check the thermostat. It may have a 165 in it which wont let the heater get real warm. I run a 180 and my heater works fine, some people put in 195's in the winter. I just run a 180 all year.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    The engine temp should be 195*.

    Could have a colder thermostat installed, or it could be that the blend door on your heater setup isn't working right, and you aren't getting the full amount of air over the heater core.
     
  4. K5HIGH

    K5HIGH 1/2 ton status

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    This Might Sound Stupid But Chek The Coolant Level 1st This Will Cause The Heat To Blow Cold Also Then Check The Thermastat
     
  5. tree_entz

    tree_entz 1/2 ton status

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    uh.. do you have the 'classic' low blow chevy heat?

    I ran 3 (yes 3) different heater fans (used) before I got smart and put in a new fan. The heat was always there...just not movin.

    does anyone have to reduce the flow over thier radiator in the winter time where you guys are from? I never liked the idea of it (could only be a 'bandaid fix') but some people end-up using cardboard in front of the radiator. Eesh, cant believe I said it, but if it's cold where your from, it's not that uncommon.
     
  6. 90gmcburb

    90gmcburb Registered Member

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    Thanks for the replys, the coolant level is good, the heater core is not clogged, so my only guess would be for the t/stat. Its only a couple of bucks so I going to replace it. Thanks again.
     
  7. 90gmcburb

    90gmcburb Registered Member

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    Well I replaced the t-stat, the old one was bad, but I am still not getting good heat. Any other ideas. Thanks.
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

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    Both heater hoses hot??

    Are both of the heater hoses getting hot??-they should if its core is not plugged up--if your truck has A/C it might have a hot water shut off valve located in one of the heater hoses to shut off hot water to the heater core when the A/C is on--if this valve is not opening or is plugged you wont get much if any heat--its usually vacuum operated,and interupts the flow of coolant to the heater core..

    It could be the "doors" in the heater box arent closing off the cold outside air and going all the way to the "heat" position too--non A/C trucks use cables to operate the doors,A/C trucks have vacuum canisters that close the doors via engine vacuum from the heater control switch..could be a dissconnected hose(might hear it whistling or hissing if thats the case) or one of the vacuum canisters might have croaked..or if its like my truck,it might have a huge rats nest built in the heater box--one time I turned the heater on in my plow truck after it sat all summer and fall,and the blower sounded like a lawnmower hitting stumps--and mice heads and blood and guts came out of the heater duct onto the floor!!:doah: :eek: :eek1: :yikes: :yikes: :yikes:
     
  9. R72K5

    R72K5 Banned

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    hey eleborate on this ! wjhere the hell were you when i posted about my friends 89 c1500 not having heat inside ??

    what fan did you end up using ?

    for 90gmcburb: definitely feel both heater core hoses when engine is hot and rmeove under cover under the heater core pass side under dash and feel all over the core for heat the core lays on its side at very very bottom cant miss it, only need to check core for heat if one hose is hot and other is cold, if neither is hot then water pump may be fudged,

    my friends 89 has problem of both very very little air moving out of anywhere, AND very little heat output, his heater core is cold and one hose cold too, other hot,

    if anyone knows what causes this 88-94 then lemme know asap please





    thanks
     

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