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Over heat on hills only

Discussion in '1982-Present GM Diesel' started by ZuluNashun, Apr 22, 2002.

  1. ZuluNashun

    ZuluNashun Registered Member

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    The other day i was driving up the mountain to do some powder surfing in the April snow, and my 6.2 temp shot up to 240 in maybe 5 min of doing 30 mph up a 6% grade. I would pull over and let it cool but as soon as it got moving up the hill it spiked hot again. This has never happened on the freeways with the throttle pegged. Could it just be the thermostat? Normal running temp is 200. Thanks
     
  2. arveetek

    arveetek 1/2 ton status

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    Thermostat, water pump, or temp. guage not reading right.

    I'd start with changing the thermostat. If you can, use RobertShaw 180 degree. They're a lot better quality.

    Casey
     
  3. ZuluNashun

    ZuluNashun Registered Member

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    Do I get that at autozone?
     
  4. René

    René 1/2 ton status

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    If the engine overheats only at large load and slow speed, then mostly is it a problem of the fan clutch.
     
  5. Tybee

    Tybee 1/2 ton status

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  6. ZuluNashun

    ZuluNashun Registered Member

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    So, does the fan clutch go out and the fan only runs at engine speed? How do I tell if my fan clutch is bad? Or should I just replace that no matter what?
     
  7. René

    René 1/2 ton status

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    The clutch is filled with liquid (silicon oil) and the fan is only moveable strongly by hand. If the clutch turns too easily, the fan is too weakly propelled and cannot cool sufficient. A e-fan is ideal in such situations.
     
  8. Oblin Goblin

    Oblin Goblin 1/2 ton status

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    Maybe theres a better way to check the fan clutch than this, but this how I would do it. The next time your truck over heats, shut if off for just a moment. Then, get out and try to spin the fan by hand. It should be difficult if not impossible to spin the fan if the clutch is engaged. Be sure to check it right after you pull off, otherwise it might start to disengage without hot air flowing over it.
     
  9. ZuluNashun

    ZuluNashun Registered Member

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    I think I'll try that. It sure gets the blood flowing when you look down and see your temp at past the red on the gauge. I got all light headed and woozy.
     
  10. Danno

    Danno 1/2 ton status

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    Yes, I second the Robert Shaw T-stat... I used part #370-180 from Autozone. About $7.
     
  11. ZuluNashun

    ZuluNashun Registered Member

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    I took it out, got it hot and tested the fan. It doesn't turn freely. There isn't a great deal of force needed to turn it. So I guess it can't be that. I'm going to buy a new therm and try that.
     
  12. DieselDan

    DieselDan 1/2 ton status

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    Might want to peer into your radiator. (Helps to see if you have a low coolant level). Mine was heating up on the highway hills (at Summer temps). I looked into the radiator and it was full of CRUD! 'Brought it to a radiator shop to have it "rodded out".
     
  13. René

    René 1/2 ton status

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    I believe that the stock radiator is large enough and can regulate smaller blockages. If several lines are closely, the engine will overheat in all operating conditions. I’ve had temperature problems only if the air condition is switched on, if transmission and engine oil are hot and few air flow are present. Since I fixed two e-fans in front of my radiator, heat isn’t a topic no more…
     

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