Help diagnosing problem?

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  • CREASE
    S2Forum Enthusiast
    • Oct 2008
    • 120
    • Home: Jersey Current: United Kingdom

    #1

    Help diagnosing problem?

    Hi all, have read every thread I can find re; coolant system/ prolems but can't find same symptoms! So here's the deal: drove home from work yesterday and noticed coolant temp higher than usual, checked levels which seemed fine. Get to work this morn and temp even higher, 110~! On my break I bleed system with car on steep slope, it takes around a litre! Run up to temp and it keeps going higher again, fan hasn't kicked in through all of this until engine off! Getting hot air through dash but expansion tank not getting hot. Main hose to top of main rad getting hot but bottom one not. Mfts replaced around year ago including connector, New mahle rad around four years, main coolant hoses two years.
    So I'm slightly confused, can the thermostat get stuck closed? If the pumps fubar would these points be hot/cold?
    Oh car is aby avant..New after run pump also.
    Any help-suggestions much appreciated!
    Cheers
  • Monkeymagic
    S2Forum Possessed
    • Mar 2012
    • 3419
    • Country: England

    #2
    If the thermo has stuck shut then the coolant will not circulate the radiator and therefore not activate the thermo switch for the fans. Try bridging the wiring for the fans and see if they are working first.

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    • CREASE
      S2Forum Enthusiast
      • Oct 2008
      • 120
      • Home: Jersey Current: United Kingdom

      #3
      The fan works, it just comes on when engine just turned off-key still in ignition....defo seems coolant isn't doing the rounds! Thanks for super quick info!!

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      • newsh
        S2Forum Obsessed
        • Aug 2003
        • 16226
        • Country: United Kingdom

        #4
        Yes, thermostats can get stuck closed and water pump impellers can fall off.

        But is the car using a lot of water? If so and in the absence of a visible leak then I would suspect the head gasket. I would put a sheet of clean card or similar under the car over night to see if it's dripping.

        S2 Coupe 3B Project


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        S2 Avant

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        • Monkeymagic
          S2Forum Possessed
          • Mar 2012
          • 3419
          • Country: England

          #5
          Is there any signs of excess pressure in the top hose. I hae seen many a VAG car when a combustion leak into the coolant system causing the system to over pressurise and stop circulating and lead to erheating and evetually blowing the header tank or next weakest point. I would certainly start with removing the thermo and testing in a pan of boiling water. If you have access to a sniffer test you can rule out head gasket very quickly.

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          • CREASE
            S2Forum Enthusiast
            • Oct 2008
            • 120
            • Home: Jersey Current: United Kingdom

            #6
            The car wasn't using any water, so I'm really hoping its not the hg! Will get the pump and thermo off on the wk-end and update here.
            What does a sniffer test entail??

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            • Monkeymagic
              S2Forum Possessed
              • Mar 2012
              • 3419
              • Country: England

              #7
              A sniffer test or block test uses a blue chemical that turns yellow if it senses exhaust gas in the header tank . You put the chemical in a. Tube and drawer gas up using a plunger on the header tank.

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              • CREASE
                S2Forum Enthusiast
                • Oct 2008
                • 120
                • Home: Jersey Current: United Kingdom

                #8
                Ok chaps thanks for all suggestions but.... Fitted new thermo, no change. New water pump fitted, no change! Flushed the rad when I did the thermostat and flowed from all connections, is there any where else that could get blocked as still don't get hot coolant at bottom of main rad meaning fan doesn't cut in!? Any ideas welcome!

                Comment

                • Error404
                  Super Moderator
                  • Mar 2007
                  • 19789
                  • Country: United Kingdom

                  #9
                  If the pump and thermostat check out ok I'd say blocked rad / hose or HG
                  Panthero Coupé quattro 20vt
                  Indigo ABY coupé
                  Imola B6 S4 Avant

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