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Radiator Overflow Cap

Discussion in 'Jeep Truck and FC Tech' started by jeepstar, Oct 20, 2023.

  1. Oct 20, 2023
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sheboygan
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    1959 fc150.
    The overflow cannister has a cap similar to a radiator. Is it the same?

    Driving to work this morning it came loose. Tightened it, it's fine. Time to replace, 2nd time its happened
     
    Ol Fogie and Glenn like this.
  2. Oct 20, 2023
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

    Grand Mesa, CO
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    The overflow tank on old vehicles probably is NOT pressurized. In that case, the cap will be a simple thread on or quarter turn unit.
    If your tank is pressurized, then the cap should have the double detent for removal. It may even have the pressure relief valve lever or the push down and twist feature.
     
  3. Oct 20, 2023
    PeteL

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

    Hills of NH
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    The overflow tank on old vehicles probably is NOT pressurized

    "Old" vehicles had no overflow tank. Only a dump tube. A holding tank is a relatively recent development. I'm surprised a '59 would have one.

    And so those vehicles had pressurized cap at the radiator. It would hold pressure to a certain value, but allow air to inflow as the radiator cooled and the coolant shrank.

    But to have a return flow from an overflow tank, the radiator neck must still hold pressure, but be arranged to instead suck overflow fluid back from the holding tank, therefore has to be fully sealed from the outside atmosphere. Different cap plumbing than the earlier type is needed at the radiator.

    But probably the holding tank cap is fully vented both ways, as the remote tank would not be pressurized, as dnb5853 says.

    So - no, not the same.
     
    Last edited: Oct 20, 2023
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  4. Oct 22, 2023
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    There is no radiator cap on an fc, just the catch can.
     
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  5. Oct 22, 2023
    PeteL

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

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    Then I don't know. Not familiar with FCs. But if the catch can is supposed to hold the necessary pressure in the cooling system, I suppose it would need a cap that functions like a conventional radiator cap.
     
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  6. Oct 22, 2023
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

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  7. Oct 22, 2023
    PeteL

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

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    Sounds about right for that era.
     
  8. Oct 23, 2023
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Part 7007 at oreillys auto parts.

    Resized_Resized_20231023_132423.jpeg
     
  9. Oct 23, 2023
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Wasn't that the cap was bad:whistle:

    1000006041(1).jpg
     
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  10. Oct 23, 2023
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Jb weld is in my future. If only I didn't scrap out an entire fc chassis last month, I would have a spare today.
     
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  11. Oct 23, 2023
    PeteL

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

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    Interesting.

    From the photos, I'd say that is less of a "catch can" and more of a remote fill. Witness that it has it seems to have its own basic dump tube, just as I cited "early" jeep radiators having.
     
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  12. Oct 23, 2023
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Here is a new one. Used to fill remotely, or catch any overflow if it surges.

    Screenshot_20231023_182818_Chrome.jpg
     
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  13. Oct 23, 2023
    PeteL

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

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    $295!!!

    How much is that in American money?
     
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  14. Oct 26, 2023
    jeepdaddy2000

    jeepdaddy2000 Active Member

    Eagle Point oregon
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    It's a remote fill, so you don't have to jack the cab to check the coolant.

    If you wanted to get super fancy, you can put a recovery tank on the overflow spout. You may need to change the radiator cap but it may be worth the effort.

    Virtually all wet automotive cooling systems from the 1940's on are pressurized. This brings the boiling point up 40+ degrees (depending on pressure and coolant mixture).
     
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