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How should I flush my cooling system?

Discussion in 'Early CJ5 and CJ6 Tech' started by ljspop, May 20, 2005.

  1. May 20, 2005
    ljspop

    ljspop Lurking Bronco Dude

    San Diego, CA
    Joined:
    Jan 29, 2003
    Messages:
    394
    I had my radiator rodded as it was pretty clogged. The rad dude ( :D that's funny I don't care who you are) said I should flush the motor too. My question is how do I do that without forcing all the stuff into my freshly done radiator? I've used radiator flush kits that plug into the heater hoses, but I'm not convinced that's gonna keep stuff outta the radiator. OR am I over thinking this and shouldn't worry about it?

    Thanks
     
  2. May 20, 2005
    Steamer

    Steamer Thick and gritty!

    SW OR
    Joined:
    Oct 17, 2004
    Messages:
    389
    Bob, if you gave me a penny for my thoughts, I'd owe you some change, but.....

    How about dropping the lower hose (the thermostat should keep any flush from the radiator, no?). Or go back and ask the rad dude. (me and th Lord are gonna check on them pygmies now)

    Stu
     
  3. May 20, 2005
    m38willys

    m38willys Jeep Vice

    Green Cove...
    Joined:
    Sep 30, 2002
    Messages:
    688
    Disconnect Both Hoses. The Upper One Is The Return. Put Your Water Hose In The Lower One And Let It Run.
     
  4. May 20, 2005
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
    Joined:
    Sep 21, 2002
    Messages:
    11,919
    For starters leave the lower hose connected and disconnect the upper hose, plus remove the thermostat. Then keep a water hose running into the radiator and start the engine and see what flushes out while it runs for a few minutes. Or do what Brannon said. ;)
     
  5. May 20, 2005
    ljspop

    ljspop Lurking Bronco Dude

    San Diego, CA
    Joined:
    Jan 29, 2003
    Messages:
    394
    That sounds like a good plan. Thanks guys.
     
  6. May 20, 2005
    beeser

    beeser Member

    Arizona
    Joined:
    Jan 8, 2003
    Messages:
    587
    Since you can't physically scour the coolant passages inside the engine similar to rodding a radiator, what chemicals are effective for cleaning prior to the flush?
     
  7. May 20, 2005
    Steamer

    Steamer Thick and gritty!

    SW OR
    Joined:
    Oct 17, 2004
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    389
    OOPS!

    looking for Bob's change now......

    Stu
     
  8. May 20, 2005
    AKCJ

    AKCJ Active Member

    Fairbanks, Alaska
    Joined:
    Aug 12, 2003
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    1,033
    I don't know what the chemicals are but it's whatever they put in that little yellow jug at the store that says "radiator cleaner". :)
     
  9. May 20, 2005
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    Aug 10, 2003
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    The active ingredient of radiator flush is oxalic acid, which actually dissolves Fe2O3 (rust). It used to be sold in a silver cardboard can, though I don't know if this powder form is still available. It had a 2-compartment can, with neutralizer in the smaller half.
     
  10. May 21, 2005
    jnutter

    jnutter New Member

    Minnesota
    Joined:
    Mar 20, 2004
    Messages:
    39
    That's the stuff I remeber from 20 years ago. 2 part can. Worked great. Wish I could find some now.

    Just went through the radiator flushing ordeal with my CJ2A/Dauntless swap. Read the FSM (left over from when I had my '60 CJ5 about a decade ago). FSM discussed flushing with a 'flushing wand' that had water flowing through and could also send blasts of compressed air through the radiator. I did my best imitation. There was a back flush fitting on the motor already. Put the garden hose on that and put the air hose up to the drain valve on the radiator and gave periodic blastsof air- with the radiator cap off. Seems to have worked great. I could see stuff blocking the tops of the tubes before I started. All that was gone when I was done. This was a relativley new and sound radiator. Try this on older radiators at your own risk.
     
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