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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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    Is the fan pulley the original size?
     
  2. Mar 14, 2021
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Pullman, WA
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    Build a tub around the engine you can fill with ice water?

    Seriously though changing the radiator can't hurt. It might be pretty restricted.
     
  3. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Can you move the alternator mount back a little bit? Is that a compressor on the far side? On board air?
     
  4. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

    Clinton, Mississippi
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    I believe so but not certain.

    :lol: I needed a good laugh. Yep, 3 core aluminum radiator meant for a v8 can't hurt.

    Not enough to offset where the PS belt runs. Yessir, It's a Mopar RV2 compressor for OBA.
     
  5. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    How about the radiator placement? Picture makes it look like it sits a bit high as in not good air flow over all of it?
     
  6. Mar 14, 2021
    3b a runnin

    3b a runnin Active Member 2023 Sponsor 2022 Sponsor

    virginia
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    Water boils at 212*, but he said he was using 50/50 mix.
    I say water pump. Or a plugged radiator.
     
  7. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    But he said a shop cleaned it.
     
    3b a runnin likes this.
  8. Mar 14, 2021
    3b a runnin

    3b a runnin Active Member 2023 Sponsor 2022 Sponsor

    virginia
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    Agree, but coolant should be flowing fairly aggressive with new water pump and clean rad. Unless the block is partially stopped up.
     
  9. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

    Clinton, Mississippi
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    They were supposed to. I know they patched and painted it. I took off the upper radiator hose and observed the water flowing out of it at different rpms. Water flow increased as the engine speed did.
     
  10. Mar 14, 2021
    3b a runnin

    3b a runnin Active Member 2023 Sponsor 2022 Sponsor

    virginia
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    What temp does it run at idle?
     
  11. Mar 14, 2021
    garage gnome

    garage gnome ECJ5 welder

    Western MA
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    Im leaning towards shroud. I'm no aerodynamics expert, so I don't know what air flowing at higher speeds on a 3B does, but a shroud on a fan does create the pull of air required for proper cooling.

    What I'm getting at is, I don't know how much air actually pushes through the radiator at different speeds.

    You could remove the stock fan and go electric. Removing the parasitic load of a fan helps with hp on these small engines.
     
  12. Mar 14, 2021
    3b a runnin

    3b a runnin Active Member 2023 Sponsor 2022 Sponsor

    virginia
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    I wouldn't think the shroud would have much effect at speed. Normally more benefit at a snails pace.
     
    dozerjim likes this.
  13. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

    Clinton, Mississippi
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    It ran up to 210 this evening and ambient temperature was 80 something. Normally it sits around 180-200.

    I like the noise it makes and mechanical fans.
     
    jeeper50 likes this.
  14. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    And I totally agree with this. :)
     
    David R Berge and dozerjim like this.
  15. Mar 14, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    One thing that we need more information about is the coolant flow. At what point have you watched the flow? Obviously removing the radiator cap when it's up to temperature isn't a good idea. Have you had it off cold, left it off and start the engine and let it warm up enough to verify the thermostat opened?
     
  16. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

    Clinton, Mississippi
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    I took the cap off while it was hot and watched and I watched while it warmed up. I took the upper hose off the thermostat housing with the engine running and watched as the thermostat opened. I cut off the engine and I could see the thermostat was in fact open.

    I'll buy a better quality mechanical gauge and test it in a pot of boiling water and Wednesday my new radiator should arrive. I'll give another update then. (y)
     
    Fireball likes this.
  17. Mar 14, 2021
    PeteL

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

    Hills of NH
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    :clap:

    An electric fan is still a "parasitic load" in some sense. The energy to run it has to come from somewhere, ultimately the engine. Some power saving might come from not having it run constantly the way a mechanical fan does without a thermal clutch.
     
  18. Mar 14, 2021
    bigbendhiker

    bigbendhiker Member

    U.S.
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    Hopefully your new radiator solves your issue. I don't know how old your current radiator is, but if it's original or of that vintage and the radiator shop didn't recore it i'd be suspicious of how well it's cooling.
     
  19. Mar 14, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

    Clinton, Mississippi
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    It was in the jeep when I got it and I threw it under the scrap pile and it sat there under a few hundred pounds of junk for two years until a few months ago. It was a wreck. I have no idea if the shop rodded the radiator. I know they didn't recore it. I was told the radiator had a few dozen holes and the man told me "like to never get it all patched up" because new leaks kept appearing. Should've left it where it was.
     
  20. Mar 15, 2021
    jeepdaddy2000

    jeepdaddy2000 Active Member

    Eagle Point oregon
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    I think you may have come full circle. I would be suspecting (coolant not moving) a blockage in the system or water pump issue.
    I know it looks correct in the picture, but could the pump be rotating in the wrong direction (This is an issue on the 258 due to two different belt systems being used)? Maybe check the impeller.
     
    dozerjim likes this.
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