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85 gmc over heating

Discussion in 'Chevy Trucks' started by rocksbite, Jan 24, 2013.

  1. rocksbite

    rocksbite Member
    Messages: 80

    gmc dually with a 350 4 speed 4wd

    i have a standard 8' meyers plow.

    when i got the truck i replaced the heater core, thermostat, flushed antifreeze, and swapped out my leaking radiator for a used one my buddy had laying around, i did flush that before install, i have the factory fan and shroud

    the last 2 snow events, on my way out the truck will run a little warm. i dont mind since i need the heat. but on my way home i cant keep it cool at all! i can understand if it was 80 degrees out. i have tryed every position i can think of for the blade.

    my first guess is the radiator isnt working well.
  2. ceptorman

    ceptorman Senior Member
    from Indy
    Messages: 208

    It only overheats with the plow on and driving? What about while you're plowing? Low on water/antifreeze? Air pocket in system?
  3. leolkfrm

    leolkfrm PlowSite.com Addict
    Messages: 1,978

    i would look closely at the fins between the cores, if they bend over with light finger pressure then get a new radiator
  4. Chiputz

    Chiputz Senior Member
    Messages: 165

    Check your fan clutch. When you turn it with the engine not running there should be some resistance. If it's stiff to turn it's fine. You can unhook the spiral thermostatic spring on the front and turn it to lock the clutch all the time.
  5. Antlerart06

    Antlerart06 PlowSite Veteran
    Messages: 3,437

    I had a 83 when I plowed I had to remove the clutch put a fix fan blade on
  6. rocksbite

    rocksbite Member
    Messages: 80

    While I'm plowing I have no problems. It seems like only when I'm above 30mph (when the fan doesn't push the air as fast the If coming through the grille. And yes only when the blade is on.
  7. Chiputz

    Chiputz Senior Member
    Messages: 165

    I had an 85 GMC that did the same thing. It was the fan clutch and I just locked the clutch like I mentioned earlier. It will run a little warmer than without the blade but shouldn't overheat. If you want to cure it all together, get a 4 core radiator and put an electric fan in it.