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  1. #1

    Default 2003 envoy xl heater core

    What all is involved in replacing the heater core in this truck?

  2. #2
    Caddiac's Avatar
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    May 2011
    Upstate South Carolina
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    I ran a search in this forum Chevy Trailblazer Forum (GMC Envoy). I found one post that did not offer much help. I searched on "heater core" but you can try a number of different key words and perhaps something will come up. It is tough learning your way around the site but you will get the hang of it. Good luck!
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  3. #3
    murdog94's Avatar
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    Feb 2008
    Cloquet, Minnesota, United States
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    You will need to remove the dash, then the heater control assembly. then the heater core should come right out, and you slide in the new one and reverse all of this.. this is a simplified version. It will take 4-8 hours and alot of nuts bolts etc. If you take your time and have mechanical knowledge and the tools i would attempt it but if you havent done one before i would find a buddy that has or else sadly pay a shop since if you do one little thing wrong you can pop an airbag or even cut a wire for anything... Not trying to sound dramatic just trying to warn you


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  4. #4


    thanks Mike. I have changed heater cores on older model trucks, but not on one like this. I was told that the AC lines have to come apart also. That is not really a problem, just trying to see what all I might be getting into. Thanks again.

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