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Poorly Thermostat?

Discussion in 'A3/S3 Forum (8L Chassis)' started by Bula_82, Jan 14, 2008.

  1. Bula_82
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    Bula_82 Self Confessed Nightmare!

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    [Jan 14, 2008]
    #1
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  3. steve1975l
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    steve1975l Member

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    [Jan 14, 2008]
    Yep it is probably stuck open.
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  4. Issac Hunt
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    Issac Hunt Active Member

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    [Jan 14, 2008]
    Should be rock solid at 90.
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  5. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jan 14, 2008]
    More likely temp sender unit. If the thermostat was stuck open then you'd reach 90 when stuck in traffic, stuck shut then you'd be overheating.
    The temp sender is a common failure and can cause running problems as well (stalling, bad idle, poor economy etc) and at £20 is a cheap and easy DIY fix so I'd swap it first before the thermostat.
    #4
  6. Bula_82
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    Bula_82 Self Confessed Nightmare!

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    [Jan 14, 2008]
    Ooh, I have bad idle too.

    Sat it was all over the place and just about not stalling, sunday it was a little high
    #5
  7. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jan 14, 2008]
    Almost definately temp sener then, it tells the ECU what the temp is so it can adjust the fuel/air misx, so if it's giving bad data the whole car can run like a bag of nails.
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  8. jesters3
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    jesters3 Active Member VCDS Map User

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    [Jan 14, 2008]
    hmm interesting...thanks.
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  9. Prawn
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    Prawn My other car is a MINI!!!!

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    [Jan 14, 2008]
    Im afraid I reckon its more than a temp sensor Sheryl!

    Mine does exactly the same, and I have replaced my temp sensor this weekend with a green one, and whilst it runs a lot better, and reaches 90 easily in traffic, it still runs down around 67 degrees (CC 49 display) when cruising on the A3.

    I have a new stat to go in, but cant for the life of me figure out how to undo the bottom bolt without moving the alternator!
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  10. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jan 14, 2008]
    As I said if it reaches 90 in traffic then its the thermostat, if not then its the temp sender, or both in your case Prawn.
    #9
  11. S3 Dave
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    S3 Dave Now running on Heavy Oil

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    [Jan 14, 2008]
    Get a small 1/4" drive socket set, **** loads of extensions and a knuckle joint then the 10mm socket its possible!!
    #10
  12. Bula_82
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    Bula_82 Self Confessed Nightmare!

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    [Jan 15, 2008]
    Cheers Nick,

    Are the parts expensive?

    Is it damaging the car at the moment?
    #11
  13. Prawn
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    Prawn My other car is a MINI!!!!

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    [Jan 15, 2008]
    I think the stat with a new seal cost me £12 Sheryl, and its apparently easy enough to change. Ill have to have another try.

    I cant see it doing any damage really, it just means the cars taking a longer time to heat up, it could possibly limit boost while its really cold, and in theroy the engine reaches its best thermal efficiency around 90 degrees, but mine been like it for about 9 months now!
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  14. 08080808
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    08080808 Member

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    [Jan 15, 2008]
    hey, sorry to just jump on but mine has been having this problem as well. only noticed it about a month ago, it drives me nuts. i changed the temp sender unit and it will get to 90 quicker but it wont sit there steady. so what i need to know is how do i change a stat and what are the part numbers please?
    #13
  15. jesters3
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    jesters3 Active Member VCDS Map User

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    [Jan 16, 2008]
    Courtesy of madvw:

    1 Fault Found:
    17704 - Error in Mapped Cooling System (usually temp Sensor or Thermostat)
    P1296 - 35-10 - - - Intermittent


    anyway.. back from audi with a new coolant sensor and o-ring, parts for a BAM are:
    A059 919 501A - C3D1 Temperature Sensor
    AN 903 168 02 - C3D1 O-Ring
    £24 +vat.
    and also the excellent how-to for a BAM engine:
    http://www.wak-tt.com/tempsensor/tempsensor.htm


    Courtesy of Prawn & S3 Dave
    For the thermostat: http://www.audi-sport.net/vb/showthread.php?t=47564&highlight=thermostat and for guides: http://forums.audiworld.com/tt/msgs/1304805.phtml

    Thermostat from VagParts
    050121113C for the Thermostat S3 £17.00+ VAT
    038121119B for the Thermostat O-Ring 57p+VAT
    #14
  16. HOUCH
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    HOUCH Member

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    [Jan 17, 2008]
    Seems to be very common fault not sure if it is due to time of year weather etc but I have had the same problem replaced temp sensor which did not cure problem bought new thermostat but took one look at where it is located and decided didnt fancy having go on driveway,took it to garage I use not sure when they started it but were only just putting enging plastics back on @ 1715 said it was a right pig of a job to get to ended up dropping alternator bracket, induction etc (not looking forward to bill) anyhoo picked up within very few mins temp up to 90 no rough juddering idle etc runs sweet now.
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  17. Pat
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    Pat Member

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    [Jan 17, 2008]
    Mine seems to run very low around 70.. then as soon as i`m in traffic goes back to 90.. would you say its the sensor..
    #16
  18. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Jan 17, 2008]
    No that's the thermostat.
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  19. jonS3
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    jonS3 Member

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    [Jan 18, 2008]
    this could be the millionth thread on this. it seems to be a very common problem.

    Like andymac says above:

    if it reaches 90 in traffic then its the thermostat, if not then its the temp sender
    #18
  20. Bula_82
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    Bula_82 Self Confessed Nightmare!

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    [Jan 21, 2008]
    I had my thermostat changed at the weekend.

    It's all running happily again now.
    #19
  21. steve1975l
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    steve1975l Member

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    [Jan 21, 2008]
    Told ya. Glad you got it sorted.
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  22. Bula_82
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    Bula_82 Self Confessed Nightmare!

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    [Jan 21, 2008]

    Nick, mine was done at home by a mate, didnt take long at all, let me know if you need any guidence :icon_thumright:
    #21

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