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Fhead Overheating

Discussion in 'Flat Fender Tech' started by 73 cj5, Mar 13, 2021.

  1. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Sounds tight enough, looked might it might be riding on the bottom of the pulley.
     
  2. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

    Clinton, Mississippi
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    It's almost flush. I'll go recheck the belt. I used the old belt to size the new one.

    .......and at $133 for a radiator, it can't hurt to try it.
     
  3. Mar 14, 2021
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    I assume this is a vacuum pump? So a theoretical maximum of 15psi Delta-P - not much of an increase over normal combustion chamber pressures. I still think it is maybe possible you have a tiny leak that only shows when the engine is working hard. I've experienced that with a plow truck that would "overheat" only when pushing snow.

    A true thermally induced overheating problem, I would expect to result in boiling over, which you say doesn't happen. :shrug:
     
  4. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

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    Correct. It doesn't boil over. I bought a new radiator. If it doesn't fix the issue then I'll try a fan shroud and if that doesn't work I guess I'll retire the current engine.

    Most of these testers have a simple bulb like a turkey baster and not a vacuum pump.
     
  5. Mar 14, 2021
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Forgive me, but if it doesn't boil why is this a problem?

    Consider that a 160ºF thermostat is sitting up front in the cool air. The temperature sender is at a hotter part of the block.
     
  6. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

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    Well, the gauge hit 230 at one point and that isn't normal....

    Every one of the fhead powered jeeps I have owned had overheating issues. :confused:
     
  7. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    My readings pretty much match what the thermostats are rated at. I've never had overheating issues. What pressure rating is your cap? 7 lbs is factory.
     
  8. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

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    I can't find a number or anything on it. :shrug:
     
  9. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    Did you check the width? Looking at the picture your belt sits down in the alternator pulley.
     
  10. Mar 14, 2021
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Okay. But I still don't understand why it doesn't boil.

    I know you said you checked against another gauge, but as little as a loose or dirty connector will give false readings.
     
  11. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    It's bugging me too, doesn't quite make sense. That's hot.
     
  12. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    Do you have an electrical or mechanical temp. gauge?
     
  13. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

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    Mechanical temp gauge and I checked it with another mechanical gauge. The belt is 1/2".

    The temp was around 200* when I checked the gauges against one another. I also checked again around 170*.
     
  14. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    You put the bypass hose on originally because of the over heating issue?
     
  15. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

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    correct. It didn't have one at all so I drilled out the pipe plug and installed the correct pipe fittings and bypass hose.
     
  16. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    I know you said you can turn the engine with the fan but the belt can be slipping at higher rpm's and you might not realize it.
     
  17. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

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    I just looked and my alternator pulley is for a 1/2" belt.
     
  18. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    If it was mine I'd get a 5/8 alternator pulley and of course a 5/8 belt. And a 7# radiator cap.
     
  19. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

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    I need a dual belt pulley to run my power steering.
     
  20. Mar 14, 2021
    Rich M.

    Rich M. Shoe salesman 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    We all have our own private little hells to burn in...
     
    73 cj5 and ITLKSEZ like this.
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