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Erratic temp gauge...

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Jp-tqs, Nov 23, 2012.

  1. Jp-tqs
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    Jp-tqs Member

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    [Nov 23, 2012]
    Hi all, got a problem......
    Temp gauge reads 90deg while driving, few mins later its bottomed out on 50deg, keep driving and its 90 again, then 50!!!!
    Temp keeps falling off, can anyone help me diagnose this please?!
    #1
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  3. marktdisport
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    marktdisport Active Member

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    [Nov 23, 2012]
    Get it scanned but I'd say coolant temp sensor is your fault
    #2
  4. Dan TheMan Welburn
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    Dan TheMan Welburn Member

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    [Nov 23, 2012]
    I started with coolant temp sensor, doesnt seem to have fixed it, im going to change thermostat next,
    #3
  5. Jp-tqs
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    Jp-tqs Member

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    [Nov 23, 2012]
    Did scan it, came up with 18062 - check memory of innstrument cluster. ??? Im thinking cts but need some reasurance from people with similar faults!
    bit worried about my fault code, should i just clear it?
    #4
  6. marktdisport
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    marktdisport Active Member

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    [Nov 23, 2012]
    my reason for cts in this case is the erratic up/down is more electrical fault thermostats gentally open and close and slightly being stuck open stopping the gauge reading 90 this makes the gauge slowly to move 60/90 etc
    #5
  7. marktdisport
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    marktdisport Active Member

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    [Nov 23, 2012]
    yes clear the fault !! Then if it comes back fix it.....
    #6
  8. Jp-tqs
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    Jp-tqs Member

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    [Nov 23, 2012]
    Think (hope!) you might be right, car gets to operating temp on gauge but just falls off! So def electrical not mechanical. What else is in the system? Stat, cts.... Anything else?!
    #7
  9. Dan TheMan Welburn
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    Dan TheMan Welburn Member

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    [Nov 23, 2012]
    yeah i understand your logic, i should of done stat first anyway as mine struggles to get to 90 always hovers between 60 and 90 and takes an age to get there, if id of used basic logic first id of sorted it first time :) suppose you live and learn though
    #8
  10. marktdisport
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    marktdisport Active Member

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    [Nov 23, 2012]
    Just these 2 items and both are very prown to failure, read so many threads about temp gauges in the last month it's untrue
    #9
  11. marktdisport
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    marktdisport Active Member

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    [Nov 23, 2012]
    yes m8 the one tell tail sign you've said above is it takes ages to get to 90 which suggests its slightly stuck open, a stat will sort you out bud
    #10
  12. Jp-tqs
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    Jp-tqs Member

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    [Nov 23, 2012]
    Can the gauge be faulty?
    #11
  13. marktdisport
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    marktdisport Active Member

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    [Nov 23, 2012]
    my opinion never say never......but IMO i wouldn't consider that yet
    #12
  14. Jp-tqs
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    Jp-tqs Member

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    [Nov 23, 2012]
    Can you get genuine coolant temp sensors online? Or is it a dealer trip?
    #13
  15. pauldazzle
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    pauldazzle Active Member

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    [Nov 24, 2012]
    I usually get all my VAG parts from TPS, always a bit cheaper than the dealer.
    #14
  16. marktdisport
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    marktdisport Active Member

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    [Nov 24, 2012]
    ive read a few horrow stories that people have changed cts and thermostat by cheaper versions and they still have faults after I would say buy at tps or stealers or of any vag specialist, I'd get both changed for piece of mind, the better it runs on 90 the better your mpg return will be
    #15
  17. Jp-tqs
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    Jp-tqs Member

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    [Nov 24, 2012]
    Been at work today so couldnt get to audi parts dept, do tps do online delivery? Want to get this sorted ready for a remap! Need it running right first though.
    #16
  18. Jp-tqs
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    Jp-tqs Member

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    [Nov 24, 2012]
    [​IMG]
    Am i right in thinking that cts is in the centre of this pic with the 2 wires on it? Just under the pipe with the vw/audi logo on it (rear of the cylinder head).
    #17

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