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Overheating

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  • Tony H.
    Very Frequent User
    • May 31, 1993
    • 537

    Overheating

    Tony
  • Jack H.
    Extremely Frequent Poster
    • April 1, 1990
    • 9906

    #2
    Re: Overheating

    Some things don't jive, Tony. If the gauge is reading 210F, the car is sitting at idle and you grab & squeeze the upper rad hose, you're either Superman or the temperature shown on the gauge is not accurate! With coolant exhausting through rubber hose, the hose will mirror the coolant temp in STEADY STATE equilibrium. I guarantee you, 'normal' humans will not be able to grab/hold a rad hose for long when its much above 190F. At 210F, you're darn near at the boiling point of water!!! Put a pot on the stove, get 'er boiling and tell me if you can put your hand inside, for how long???

    Point is human body is 90% water and boiling point is destructive to life/limb. Hence, conditioned reflex won't let you get near such temperatures UNLESS you had some kind of special training (Zen, Navy Seal, Etc.). So, I start with an intrinsic doubt about the accuracy of your temp monitoring system (guage and sender). Instead of guessing, grab an oven meat thermometer, affix it to your outlet hose with insulating electrical tape, crank up the engine, get 'er up to temp and read the thermometer vs. the dash gauge. Time to put science to work vs. guesstimation....

    Comment

    • Jack H.
      Extremely Frequent Poster
      • April 1, 1990
      • 9906

      #3
      PS

      Forgot the second part of your post -- "What could cause this?"

      Temp measurement system is in-line ammeter to ground (engine block) through a non-linear variable resistor (temp sender). If there's another path to ground in parallel with the temp sender (consider conductive debris across the bakelite insulator surrounding the temp sender's terminal post), you're effectively lowering the resistance of the temp sender and thereby increasing current flow through the ammeter with an associated elevation in reported temperature.

      In Shark cars that originaly used 'pin head' senders and 'barrel' connectors, the temp sender lives in a 'hostile' environment (side of cylinder head directly below the ramshorn exhaust manifold. This is ALSO a place where coolant overflow from loose hoses, gaskets AND oil blow by from loose fitting valve covers is likely to seek out....

      Comment

      • Tom B.
        Very Frequent User
        • February 1, 1994
        • 779

        #4
        Re: Overheating

        Tony,

        I can agree with Jack in the sense that your temperature monitoring system, the temp sending unit and gauge, should be some of the first things to check. And in your case some of the symptoms you mentioned may indicate temperature indicator problems, IF your engine is truely not getting up to temp.

        But I think your engine is getting up to temp, and I read more into your problem than just a faulty temperture wiring system or it's components. I think you drove the car a long enough period of time to find out, plus why else would it be spitting coolant if the temperature wasn't high? The second thing is where's all your system pressure? My first thoughts are that your new radiator cap isn't holding pressure or that your water pump isn't working correctly. Trying another cap is easy enough, but I'd wait to hear more from others before changing out the pump.

        Also, with so many different cooling problem "checks", there could be more to look over if these few suggestions don't start working out or correcting the problem. TBarr #24014

        Comment

        • Tom B.
          Very Frequent User
          • February 1, 1994
          • 779

          #5
          Re: Overheating add on.

          Tony,

          Is your alternator belt adjusted for the correct tension, not too tight, and not too loose? TBarr #24014

          Comment

          • Jerry Clark

            #6
            Re: Overheating

            Hi Tony:

            It took me three tries to obtain a correctly functioning RC26 from a major vendor, all the caps tested incorrectly when pressure tested, at the price they get for these caps you would think it wouldn't be too difficult to get the only critical aspect correct.

            jer

            Comment

            • Tony H.
              Very Frequent User
              • May 31, 1993
              • 537

              #7
              Re: Overheating add on.

              Yes, Tom, alternator belt is properly tensioned.
              Tony

              Comment

              • Dave, NCRS#24235

                #8
                Re: Overheating

                If Jerry's suggestion about the cap isn't it, have you replaced/looked at the LOWER radiator hose lately. If the internal steel spring dissolves, the pump sucks the hose flat. - Dave

                Comment

                • Tony H.
                  Very Frequent User
                  • May 31, 1993
                  • 537

                  #9
                  Old Thermostat is OK

                  I just checked the old thermostat that I removed from the engine. It opens up just fine in a pot of boiling water. Tomorrow, I will test the new radiator cap.
                  Tony

                  Comment

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