5.3 overheats when going up mountains. Any ideas?

Discussion in 'G-Body LS Swap' started by 20Grand, Jun 13, 2018.

  1. 20Grand

    20Grand Apprentice

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    I’ll lose almost 1.5 gallons of coolant when going up mountains. I have a 5.3, 4l60e with stock v6 gears. I think 273s or something like that. Anyways, any ideas? Could it be that my rear end is pulling my motor abdctrans down? I have a 1k treck back home and I’d like to make it.
     
  2. oldsmobile joe

    oldsmobile joe G-Body Guru

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    If its only overheating when at altitude, I'd check your radiator cap. Make sure its keeping the correct pressure in the cooling system.
    Also, is your coolant the proper mixture. 50/50 antifreeze to water is the easiest to install. Remember, antifreeze is also an anti-boil liquid.
    Science class time, everything boils at a lower temp the higher up you go. Water boils at 212f at sea level but drops to about 200f at 5000 ft. Or something like that. Same idea applies to coolant.
     
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  3. UNGN

    UNGN Royal Smart Person

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    Do you have a radiator support air dam? What is your thermostat? Does it have electric fans?

    I doubt it was the 2.73 gears. Even if it was, you could always put it in D to take the load off.
     
  4. pontiacgp

    pontiacgp Canadian Prime Minister

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    Is it overheating or are you just losing coolant?
     
    #4 pontiacgp, Jun 13, 2018
    Last edited: Jun 13, 2018
  5. Turbolq4

    Turbolq4 G-Body Guru

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    Do you have the steam line from the heads hooked up?

    Do you have an overflow tank?
     
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  6. motorheadmike

    motorheadmike Royal Smart Person

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    That coolant had to go somewhere: either into the combustion chamber or out onto the road.

    Time to pressurize the system and see.
     
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  7. olds307 and 403

    olds307 and 403 Comic Book Super Hero

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    What temp are you reaching? Tell us everything, rad, fan, shroud, air dams, coolant mix, thermostat etc.
     
  8. 20Grand

    20Grand Apprentice

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    Brand new cap but I can go pressure test it once more. How important is the overflow tank? The threads melted when it overheated on the way over here. Also, I’m running 16lbs, that sound about right? I’ll drain and mix with 50/50 before heading out.
     
  9. Texas82GP

    Texas82GP Comic Book Super Hero
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    Do you have a high stall speed torque converter? You might need an auxiliary trans cooler.
     
  10. pontiacgp

    pontiacgp Canadian Prime Minister

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    that is kinda important to know.....(y)
     
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