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Temperature

Discussion in 'A3/S3 Forum (8L Chassis)' started by Jay, Feb 7, 2008.

  1. Jay
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    Jay Member

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    [Feb 7, 2008]
    The needle seems to fluctuate between 70 and 80 and rarely reaches 90 degrees. I get the same problem if in traffic or on the motorway.

    Is it the temp sender or thermostat?

    Nothing coming up on VAGcom either.
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  3. Stewart
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    Stewart Member

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    [Feb 7, 2008]
    Usually thermostat but sometimes both.
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  4. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    Thats normal aint it, mine does the exact same unless I am in still traffic for a length of time and then it goes to 90 and the fan cuts in. Had mine inspected and VAGcom'd as part of a service and no faults
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  5. Jaywoo_A3
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    Jaywoo_A3 Audi dead, 2.0T all the way!

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    [Feb 7, 2008]
    I changed the thermostat on mine and now it goes straight up to 90 after about 5 minutes and stays there, before it was taking ages to warn up then fluctuating all over the place.
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  6. joshW
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    [Feb 7, 2008]

    same here!!

    josh
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  7. Stewart
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    Stewart Member

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    [Feb 7, 2008]
    No it's not normal, as Jaywoo says, it should go up to 90 and sit there and not fluctuate.
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  8. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    Looks like I have the same problem then, does it mean the engine is not warming properly or its just not reading the correct temperature properly?

    My car had a major service and they didnt mention anything about it, I think I want to go back to Honda :(
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  9. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Feb 7, 2008]
    If it's the temp sender, then it means the car is warming up to the correct temp, but the ECU thinks it isn't so you'll get increased fuel consumption and/or bad idle/stalling.
    If its the thermostat stuck open then it means your engine is running too cool when on motorway/open road (travelling at 40mph+), but should be at correct operating temp when stuck in traffic when there isn't any significant airflow over the RAD.
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  10. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    I assume the correct temp is 90?

    Mine warms to about 79ish when normal driving, motorway etc, if I pull up and turn the engine off a few minutes and come back to the car the temp is at 90 when its started but soon drops to 79ish again. Guess I need to replace my thermostat, is it an easy DIY job? God I hope so I am sick of my car going in the garage! Any walk through's? Cost of the part?
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  11. noodle
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    noodle Member

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    [Feb 7, 2008]
    I seem to be having a similiar problem wherby sometimes the needle takes ages to get to 90 whilst travelling, but if I sit in traffic it seems to get to 90??

    I had the same problem tonight where it only got quarter across and stayed there for the 35 mile drive home.

    Is this easy to fix?
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  12. j4jon
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    j4jon Member

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    [Feb 7, 2008]
    Realatively straight forward but fiddly. The thermostat is about £15 the o ring £2 ish and about £6 for the G12 coolant. I did one an an A3 last weekend probably 30 mins to an hour depending if you keep dropping the bolts or not.
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  13. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    Anyone want to buy an A4 1.8TQS! Think I have had enough!
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  14. j4jon
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    j4jon Member

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    [Feb 7, 2008]
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  15. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    Thanks mate, looks like a pain in the arse. Cant beleive I have to book it in again, getting annoyed with this car its costing me a fortune
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  16. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Feb 7, 2008]
    That won't be the thermostat. If it's the thermostat then it'll reach 90 when idling or crawling along in traffic, but cool off when picking up a bit of speed. This will be consistent as the thermostat will be stuck open so letting the coolant through the rad regardless of engine temp, when it should shut off the rad when below operating temp.
    Sounds more like the temp sender to me if it's behaviour is inconsistent.
    Either way it's a lot easier to replace the temp sender first, £20 from dealer and a 20 minute DIY fix.
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  17. j4jon
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    [Feb 7, 2008]
    After doing it once, I can agree with that, not sure I'd do another one in a hurry. Thats the thermostat i'm talking about the temp sensor is far easier
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  18. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    If I get stuck in traffic it does warm to 90 but takes a while, its when the cars moving that it drops down again, even slow moving. Sorry should of said that before, still think its thermostat or temp sender?

    Is it not recomended to run the car like this, its basically running 10 degrees lower than it should be
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  19. j4jon
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    j4jon Member

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    [Feb 7, 2008]
    Have you checked what the climate control reads when the dash reads low?
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  20. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    The climate control? Sorry I dojnt know what you mean?
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  21. Issac Hunt
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    Issac Hunt Active Member

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    [Feb 7, 2008]
    You can read the engine temperature on the climate control panel, Do a search for the procedure.

    I'd change the temp sender first, quick and easy to do.
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  22. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    Had a search and a read but didnt really help me, I will just get the whichever part needs replacing replaced.

    Best way to check, I think...

    My car has been plugged into vagcom twice in the last two months with no codes, I am guessing here but because the sender is electronic if it was faulty it throw a code?

    As there is no codes and from a quick search there seems to be people having similar probs to me it would seem it is the thermostat stuck open?
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  23. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Feb 7, 2008]
    Yes definately thermostat
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  24. Issac Hunt
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    [Feb 7, 2008]
    The temp switch wont always throw a fault code, the thermostat obviously wont!

    If it was mine then I'd replace both at the same time. Overkill maybe, but I like to know evreything is sorted. For what its worth when I changed the cambelt and water pump on my old Golf I also popped in a new temp switch and thermostat.

    No problems were evident with either but as the car had covered 65k at the time I figured it wouldnt be too long before I'd have to mess about and drain the coolant again!
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  25. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    Ill just get both replaced, as its a Quattro please tell me its not a front end off job again to replace both of these parts!?

    As I am skint I cant get it done for a few weeks due to spending over £700 on the car in the last few weeks, I cant see it as major prob running at 80 and not 90 for now
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  26. j4jon
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    [Feb 7, 2008]
    Press and hold the air recirc button and the up arrow (the one to direct the air up to the screen) The screen should change to displaying 1C. Then press the temperature plus button, the display should increase to 2C, 3C etc. You need to go up to 49C, then press the air recirc button again the display should change to display the temperature the ECU is seeing from the temp sensor.

    The temp sensor has two parts one that feeds the dash and one that feeds the ECU, one half can fail whilst one part still reads correct. You need to compare the value displayed on the dash to that displayed on the climate panel.
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  27. Issac Hunt
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    Issac Hunt Active Member

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    [Feb 7, 2008]
    You wont need to remove the front of the car! I would estimate around 90 minutes maximum to do the job.

    Follow the guides on the 'net and save yourself a fortune, gives a nice sense of satisfaction not having to shovel cash into someone else's pockets:icon_thumright:
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  28. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    Yeah I know what your saying, I have done jobs on my own cars before and it is very satisfying but that thermostat job looks like a right nightmare. Does anyone have a guide to the temp sender swap? I might give that a whirl if its straight forward just to cancel it out of the equation

    Glad the front doesnt have to come off though

    Thanks for the info j4jon but I am going to replace the temp sender anyway, after searching it seems cheap to do and it seems fuel consumption and performance can be affected by older parts so I feel its worthwhile doing both parts anyway
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  29. j4jon
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    [Feb 7, 2008]
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  30. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    Yeah that swap looks very straight forward, I will get one ordered up tomorrow and see if the fault remains when swapped. If so then the thermostat can get done, I might be daring and attempt that myself too!

    Thanks for all the help, very much appreciated
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  31. Issac Hunt
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    Issac Hunt Active Member

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    [Feb 7, 2008]
    Temp sender is easy, Thermostat is a little fidly but not difficult if you do it with the engine stone cold and follow the pictures posted above.

    Whenever I'm struggling with a job on my car I always think to myself -'If some YTS monkey at Audi/wherever can do it then I'm damn sure I can'

    Always seems to work for me:thumbsup:

    Its only nuts and bolts at the end of the day, and not many at that.
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  32. Bong Water
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    Bong Water In two minds

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    [Feb 7, 2008]
    Now theres a vote of confidence! :)

    Think I might give it a whirl with the old fella, he is handy with a spanner and is always up for working on the motors
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  33. j4jon
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    j4jon Member

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    [Feb 7, 2008]
    Your better off with small hands and a magnetic thingy, just try not to a) snap the dipstick tube and b) drop the bolts
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  34. Jay
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    Jay Member

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    [Feb 8, 2008]
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  35. Bong Water
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    Bong Water In two minds

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    [Feb 8, 2008]
    I did the climate control thing this morning and the reading never went over 73 in 20 mins whilst the dash continued to read its regular 79, strange that the readings dont match, looks like I need to replace both the temp sender and the thermostat anyway, or does that just indicate temp sender if the ECU is reading wrongly?

    Jay, ill try and get a price on a thermostat from my dealer this morning, not sure if it will be the same part as yours though
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  36. Jaywoo_A3
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    Jaywoo_A3 Audi dead, 2.0T all the way!

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    [Feb 8, 2008]
    Deffinatly sounds like your thermostat if the Climate and dash both read low.
    I found the dealers want £13 but Q&H one's from halfords are about a fiver.
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  37. Bong Water
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    Bong Water In two minds

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    [Feb 8, 2008]
    Just paid £28 for a temp sender and O Ring, thermostat was £18 with the O ring but no stock both from main stealer

    I am replacing both but ill do the temp sender tomorrow

    Thanks all
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  38. nik patel
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    nik patel Member

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    [Feb 8, 2008]
    Jay/Bong water i have the same problem. But i changed the temp sensor about 5 months ago with VAG one so dont think it could be that again. Please advise how you get on with it
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  39. Jay
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    Jay Member

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    [Feb 8, 2008]
    Do you have a quattro ?

    How different is replacing the sender and thermostat compared to a facelift A3?

    Maybe you could post some pictures of the swap out if its not a pain in the arse?
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  40. nik patel
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    nik patel Member

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    [Feb 9, 2008]
    Guys do u have any tips to when changing the thermostat??

    Looks straight forward but just fiiddly, what you need the magnetic thing for? i can hardly see the bottom bolt. Also any tips on not how to break the dipstick holder:idea:
    #39
  41. j4jon
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    j4jon Member

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    [Feb 9, 2008]
    Just order a new dipstick tube, from speaking to audi they are about £2.50 maybe a tad more then you are prepared for when you do break it. The magnetic thingy is to get the bottom bolt in and out without dropping it.
    #40

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