Engine Cooling Fan

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  • jade
    S2Forum Extremist
    • Jan 2005
    • 1811
    • Home: New Zealand Current: Spain

    #1

    Engine Cooling Fan

    I have Problem with cooling fan not kicking in, I have changed the Radiator Sensor and can make it all work as it should with a little jumper wire

    But under way will not kick in temperature just gets hotter, Unless I turn the A/C on then the fan starts to run on speed 1

    Any Ideas
    RS 2 580HP
  • twoqu
    S2Forum Possessed
    • Sep 2003
    • 3103

    #2
    Might help if you share with us how you get it to work with the jumper wire.
    The A/C and after run are on a seperate circuit to the rad fan speeds. Lets call them 1st Stage.
    The 2nd stage is the ordinary speed fan. This has its own circuit.
    The 3rd stage is the high speed. This has its own circuit.
    So are you saying you have neither 2nd and 3rd?

    Comment

    • Rikki Kitto
      S2Forum Zealot
      • Feb 2010
      • 6276
      • Country: England

      #3
      Mine did this recently, MFTS on the water manifold

      Comment

      • twoqu
        S2Forum Possessed
        • Sep 2003
        • 3103

        #4
        Originally posted by Rikki Kitto
        Mine did this recently, MFTS on the water manifold
        The MFTS has no control over the radiator fans whatsoever. It provides engine temp signal to the coolant gauge, an overheat signal to the dash and to the ECU to limit boost.

        Comment

        • jade
          S2Forum Extremist
          • Jan 2005
          • 1811
          • Home: New Zealand Current: Spain

          #5
          Originally posted by twoqu
          Might help if you share with us how you get it to work with the jumper wire.
          The A/C and after run are on a seperate circuit to the rad fan speeds. Lets call them 1st Stage.
          The 2nd stage is the ordinary speed fan. This has its own circuit.
          The 3rd stage is the high speed. This has its own circuit.
          So are you saying you have neither 2nd and 3rd?
          Plug jumper wire into Radiator plug and touch it on one of the contacts that operates spd 2 other speed 3, I have also heated the old sensor with a blow torch and that activated Spd 2

          neither speed 2 or 3 are kicking when rad is boiling
          RS 2 580HP

          Comment

          • twoqu
            S2Forum Possessed
            • Sep 2003
            • 3103

            #6
            Well if you have jumpered the radiator temperature switch and the fan works on either or both speeds then it indicates the actual temperature switch in the rad. Thats the whole point about bypassing a component using a jumper wire. You are dong what the switch does. When it reaches the temperature it closes the contact sending power to the relay to trip the fan speed. The two outputs are for the different temperatures.
            Not sure what temperature a blow torch outputs but I guess its more than 100C!
            So either the new sensor is faulty or is incorrect in terms of the contact closing temperatures.

            Comment

            • twoqu
              S2Forum Possessed
              • Sep 2003
              • 3103

              #7
              A quick test without much in the way of test equipment would be to remove the temp switch, dangle it in a source of heated water and connect a multimeter between the input contact and the 2nd stage contact. Set the MM to Ohms. It should be open circuit until the water nearly boils then it should be closed. You could refine this process with a thermometer. The switch closes at something like 95C. Obviously if its not closed when the water is boiling (100C) then its not doing what it should. You can also wait for the water to cool down and see if the switch opens again.
              Difficult to check the 3rd stage as you need a temperature higher than 100C!
              Last edited by twoqu; 22 September 2013, 12:36.

              Comment

              • Rikki Kitto
                S2Forum Zealot
                • Feb 2010
                • 6276
                • Country: England

                #8
                Really? it was definitely that which caused the fan not to work I changed it back and forth to double check.

                Comment

                • twoqu
                  S2Forum Possessed
                  • Sep 2003
                  • 3103

                  #9
                  I would test the switch as described to check its function. If it operates correctly then the only other issue is what the temperature is in the bottom vs the top of the radiator. If the switch works that leaves an issue with the radiator itself or perhaps a coolant circulation issue. Perhaps the thermostat.
                  Last edited by twoqu; 22 September 2013, 12:49.

                  Comment

                  • twoqu
                    S2Forum Possessed
                    • Sep 2003
                    • 3103

                    #10
                    Originally posted by Rikki Kitto
                    Really? it was definitely that which caused the fan not to work I changed it back and forth to double check.
                    If you are talking about the MFTS in the coolant manifold on the cylinder head then as far as I am aware its functions are exactly as I outlined. Thats why the cooling fan speeds are seperate and multiple. If one fails you might get away with another!

                    Comment

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