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How hot is "Running Hot"?

Discussion in 'Early CJ5 and CJ6 Tech' started by one2manyjps, Apr 23, 2008.

  1. one2manyjps

    one2manyjps Member

    I have a '69 cj5 w/ 225 V6. :v6: Temp gauge shows 210-225. Seems pretty hot under hood. Is this good? :? When looking into radiator as thermostat opens, water occasionally circulates...should it circulate constantly? and is this a water pump problem? :( just replaced thermostat.

    My '48 cj2a runs about 180 degrees.

    Thanx,
    Bob in Arkansas
     
  2. sparky

    sparky Sandgroper Staff Member Founder

    First the thermostat should only open and close at the set temperature so water should not continuously circulate. The engine would never reach full operating temperatures if it didn't behave this way.

    Second, you could try a new thermostat in it if you like, but unless it's overheating or acting up (like mine has before) what's the issue?

    Mine will get hot but not overheat. When it does it starts stalling out and sputtering on hill climbs. Once cooled off or on the highway with lots of air flow it's fine.
     
  3. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    I would try and calibrate my temp gauge. The first and easiest experiment would be to put a thermometer in the radiator and compare the coolant temp to the gauge. I'd use a lab thermometer, since I have one, but you can improvise something. If the gauge says 225F, the coolant is above boiling and might geyser if you take the cap off, so be careful. Next you could get a cup of hot water, take the sending unit out of the block but still connected to the wire, dunk it in the water, and compare the water temp to the gauge temp. Note that, with the sender out of the block, you'll need to ground the body of the sender to the block using a clip lead or such.

    Sparky's right about the temperature cycling. The thermostat is supposed to keep the temperature at the set point, so it should open and close in normal use. If the thermostat is open all the time (ie always above the set point) you no longer have control of the temperature, and the temperature will rise and fall with the load on and speed of the engine.
     
  4. one2manyjps

    one2manyjps Member

    Thanx, Guys! Guess I'll not do anything unless a problem develops. Bob in Arkansas
     
  5. EricM

    EricM Active Member

    I got a non contact temp gauge from harbor freight. I aim it at different parts of the radiator and the engine.
     
  6. DrDanteIII

    DrDanteIII Master Procrastinator


    Thats actually how my 304 runs in the summer, always above the t-stat temp (180). But I've got a big noisy electric fan that cycles the temp between 215 to 185. I whould probably calibrate te fan down a bit to sync with the t-stat, but its always worked fine, and never overheated on me, so i havent messed with it.

    Anyway, like stated above, unless your motor is overheating, it sounds like its operating just fine. You could always swap down to a 190 or 180 stat if you feel that its too hot for you.
     
  7. TexColorado

    TexColorado Member

    I have headers on my Jeep and I have been told that will make Buick's run hotter. This is from a Buick guy, not a Jeep guy but he is still knowledgable.

    I have built myself a fan shroud, run the stock engine fan, use a 180 degree thermostat, use a larger radiator (4 core) which was rebuilt 2 years ago, and have a backup electric fan. All this and my engine still runs on the hot side but it doesn't go out of control.

    The temp will creep up above 200 sitting at a light in summer and fall right away when I hit the accelorator. Running on trails in the summer I will run my electric fan just about constantly (it is a manual toggle switch, not thermostat controlled).

    I am good with how my Jeep runs now.