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Dang Radiator cap

Discussion in 'Early CJ5 and CJ6 Tech' started by BenB, Jun 29, 2007.

  1. Jun 29, 2007
    BenB

    BenB Member

    Stevensville, MD
    Joined:
    Jul 30, 2006
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    I replaced the water pump a few months ago and I finally got around to plumbing the heater yesterday. I also decided I should replace my radiator cap because it is getting old. The one I had was a 5lb and the replacement was a 14lb(I am assuming this is the pressure require to open it allowing it to vent out the vent line). I drove it this morning for approximately 3 miles and some guy flags me down and tells me I'm leaking something. I get home and the radiator is empty and everything looks ok(besides the lack of collant). I filled it up and drove to a gas station, I pulled over half way and opened the hood to discover that it was draining out of the vent line. I took of the old radiator cap added some water and put the old cap back on. No more leaking. Should I assume that the FLAPS sold me the wrong radiator cap. Can anybody tell me what part number or model they are using. Thats what I get for trying to replace something before it goes bad.
     
  2. Jun 29, 2007
    BenB

    BenB Member

    Stevensville, MD
    Joined:
    Jul 30, 2006
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    I spoke to soon. I was driving back to work this afternoon and I started losing coolant out of the vent line. Does it matter what port on the water pump housing the heater line runs into.
     
  3. Jun 29, 2007
    dohc281

    dohc281 It is what it is.

    Laurel Springs, N.J.
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    Dec 30, 2004
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    I had the same problem with my Hurricane and the problem ended when I drilled a small 1/8th inch hole in the thermostat.
     
  4. Jun 29, 2007
    BenB

    BenB Member

    Stevensville, MD
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    Jul 30, 2006
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    Where in the thermostat did you drill the hole.
     
  5. Jun 29, 2007
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Sep 21, 2002
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    The heater hose goes to the port on the passenger side of the pump.
     
  6. Jun 29, 2007
    dohc281

    dohc281 It is what it is.

    Laurel Springs, N.J.
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    The flat piece that opens and closes.
     
  7. Jun 30, 2007
    BenB

    BenB Member

    Stevensville, MD
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    I guess that was kind of a dumb question. It's was a long week.
     
  8. Jun 30, 2007
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
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    Jul 30, 2003
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    just out of curiousity...
    are you filling the radiator up to the bottom of the neck ?
    it is normal for it to push out coolant to about 1" below the neck opening.
    just a normal expansion process when warmed up or afterboil when shut off.
     
  9. Jun 30, 2007
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

    San Diego,...
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    By his original post it sounds like the radiator was empty not just low.

    Ben, you said you replaced the water pump several months ago. I assume you ran it then and there were no problems at that point. I can't imagine why the cap would cause that quick of a coolant loss. Have you tested the thermostat?
     
  10. Jun 30, 2007
    BenB

    BenB Member

    Stevensville, MD
    Joined:
    Jul 30, 2006
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    Just started loosing coolant when I reconnected the heater line. There are two ports on my water pump body. When I reconnected it I used the driver side port. I found out that the heater should be run through the passenger side port. I haven't had time to run the jeep yet today so maybe tonight or tomorrow. I replaced the radiator cap when I reconnected the heater. So it might not be a radiator cap problem.

    Yeah, it was pretty empty both times it decided to "jettison" the antifreeze.
     
  11. Jun 30, 2007
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I believe the correct cap pressure is 7 lbs, I'm sure 5 is close enough though.
     
  12. Jun 30, 2007
    WYOMIKE

    WYOMIKE Oct 1971 pic

    Parkman, Wyoming
    Joined:
    Jan 22, 2003
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    685
    Don't know what engine you have but if its a V-6, then the 14# was ok, If is the 4, then it could be eather a 7# or 15# See below from the FSM. :)

    View attachment 18618
     
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