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F head running hot

Discussion in 'Early CJ5 and CJ6 Tech' started by 1968Jeep, Jul 30, 2007.

  1. Jul 30, 2007
    1968Jeep

    1968Jeep Member

    St.Albert,...
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    Apr 12, 2003
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    At any speed above 30 mph, the temperature gauge is running between 200 to 230 degrees - with a 160 degree thermostat, the heater at full blast, and the electric rad fan running in addition to the mechanical engine driven fan.
    coolant is a 50/50 mix.
     
    1968Jeep, Jul 30, 2007
    #1
  2. Jul 30, 2007
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
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    Have you "burped it yet" F heads are know for having air trapped.
     
    blevisay, Jul 30, 2007
    #2
  3. Jul 30, 2007
    1968Jeep

    1968Jeep Member

    St.Albert,...
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    the coolant level has been consistant for a few weeks now, I had a 195 thermostat in it for the winter, but decided to change it out when I heard the fuel boiling in the float bowl - does not actually boil over, but really seems hot to me...
     
    1968Jeep, Jul 30, 2007
    #3
  4. Jul 30, 2007
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
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    Gimmie a sec,
     
    blevisay, Jul 30, 2007
    #4
  5. Jul 30, 2007
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
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    blevisay, Jul 30, 2007
    #5
  6. Jul 30, 2007
    1968Jeep

    1968Jeep Member

    St.Albert,...
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    I am going to replace the thermostat, and burp the system again, then recheck everything. My motor does have the small bypass hose installed as well.....
     
    1968Jeep, Jul 30, 2007
    #6
  7. Jul 30, 2007
    1968Jeep

    1968Jeep Member

    St.Albert,...
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    I am also running that "water-wetter" stuff - did not seem to make any difference....
     
    1968Jeep, Jul 30, 2007
    #7
  8. Jul 30, 2007
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Portland Tn.
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    There is the 1/8 hole trick as well.
     
    blevisay, Jul 30, 2007
    #8
  9. Jul 30, 2007
    1968Jeep

    1968Jeep Member

    St.Albert,...
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    the funny thing is, the temperature never spikes and drops - it just gets hotter and hotter - then sits around the 220 mark.... no bubbling or spitting up of coolant at all....
     
    1968Jeep, Jul 30, 2007
    #9
  10. Jul 30, 2007
    Vanguard

    Vanguard Take Off! Staff Member

    Vista, CA USA
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    Betsy needed burping on a couple of occasions. I found the best cure to be using a cheap Prestone backflush kit. Get's the crap out and seemed to prevent air pockets.
     
    Vanguard, Jul 30, 2007
    #10
  11. Jul 30, 2007
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Do you have an electric gauge, or is it mechanical?
     
    Glenn, Jul 30, 2007
    #11
  12. Jul 30, 2007
    1968Jeep

    1968Jeep Member

    St.Albert,...
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    mechanical - Sun-Pro gauges -
     
    1968Jeep, Jul 30, 2007
    #12
  13. Jul 30, 2007
    1968Jeep

    1968Jeep Member

    St.Albert,...
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    The weird thing is, if I am idling around on the trail, the temp usually sits right around 160 to 190 or so, it's not until I need to work the engine a bit it starts to get hot. Then after I shut it off, I can hear the fuel boiling in the float bowl.
     
    1968Jeep, Jul 30, 2007
    #13
  14. Jul 30, 2007
    kiowamtp

    kiowamtp Member

    DFW
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    You could check your timing as well.
     
    kiowamtp, Jul 30, 2007
    #14
  15. Jul 30, 2007
    evanjm

    evanjm Yeah, it's got an F-head.

    Leesburg, VA
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    not to sound stupid here, but what do you mean by 'burping'? just getting rid of the air in the system?

    how do you do that? i've never done that when flushing the coolant on mine before... maybe i should be?

    - evan
     
    evanjm, Jul 30, 2007
    #15
  16. Jul 30, 2007
    lamar

    lamar Member

    greenville sc
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    i had 70 cj once over heating like yours.it turned out to be my radiator.it was partially clogged up.radiator shop recored it and problem was solved. as for the carb. i put a weber on and it would boil also. that problem turned out to be the float level to low.i raised the level up a little and it stoped. seemed ,as for as i can figure, the lower amount of gas in the carb. would heat up faster and boil.when more gas was in it,it would be enough gas to only vaporize ,and thus stay cool enough not to boil. hope this makes sence and helps you.
     
    lamar, Jul 30, 2007
    #16
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