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A3 1.8T Thermostat!

Discussion in 'A3/S3 Forum (8L Chassis)' started by AudiiduA, Feb 23, 2010.

  1. AudiiduA
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    AudiiduA Member

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    [Feb 23, 2010]
    Hi all, newbie here!having picked up my new car tonight i notice while normal driving the temp gauge is just over 60 degrees,hardly moved at all, but in traffic came up to 90 and stayed there untill i started moving again! could this be the stat? how much are they and are they an easy DIY?
    Thanks in advance fellas!
    Lee:icon_thumright:
    #1
  2. A3Monster
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    A3Monster Faster pussy cat!

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    [Feb 23, 2010]
    Hi,

    Mine does this. I had the water pump replaced as normal with the timing belt and I got my garage to check the stat. There was nothing wrong with it so they told me not to worry. More likely the sender unit I'm told so may get that done eventually. As long as I know the engine is actually keeping temp ok I don't mind it at the moment.

    cheers.
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  3. AudiiduA
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    AudiiduA Member

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    [Feb 23, 2010]
    With the engine running so cool, wouldnt that affect economy? all your fueling would be running richer for more of the time and thats gotta be bad?
    #3
  4. Matt82
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    Matt82 Active Member

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    [Feb 24, 2010]
    how do you "know" that? the gauge is only going to 60

    Auduudua is correct. the car ends up running rich
    #4
  5. will.f_1.8t
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    will.f_1.8t Member

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    [Feb 24, 2010]
    mine also does this, but only started after i got the water pump/cambelt! i was also going to change the thermostat for peace of mind!
    #5
  6. Welly
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    Welly VX220 SC Driver :)

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    [Feb 24, 2010]
    Thermo change is an easy DIY job.

    Buy one and a gasket from Audi - not that expensive (I forget how much).

    Remove engine covers. Remove metal part bolted to the underside of inlet manifold (connects to the dipstick pipe*).

    Drain coolant from engine using tap on radiator bottom hose.

    Release tensioner for aux belt using a 15mm spanner and small allen key (acts as a pin) to lock tensioner.

    Undo Alternator's top bolt and remove, slacken lower bolt. Remove main wire from right hand side of alternator. Pull alternator forward.

    You will now be able to see (and more importantly - access) the black plastic hard pipe going into the block. 2 x 10mm hex bolts. Undo. (be prepared for some coolant loss) Remove. Pull out thermo. Replace with new. Put new O ring over.

    Reverse above process.

    Easy peasy.

    * Be warned that plastic dipstick pipes can be brittle and are likely to crack.
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  7. Welly
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    Welly VX220 SC Driver :)

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    [Feb 24, 2010]
    That could be due to more efficiency in the water system, higher pressures due to a more effective pump...
    #7
  8. AudiiduA
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    AudiiduA Member

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    [Feb 24, 2010]
    Cheers for that Welly,i let it idle for about 30 mins today,it came to 90 degrees and stayed there, so u recon over effecient water pump?
    #8
  9. feville
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    feville Frank

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    [Feb 24, 2010]
    I am also having this prob and planning on changing my stat at the weekend, does anyone know if the ECU will limit boost while engine is running low temps? (mine sits on 60 whilst moving)

    Cheers!
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  10. Welly
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    Welly VX220 SC Driver :)

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    [Feb 24, 2010]
    No such thing as an over efficient water pump..... only an under effecient thermo.....

    Its letting too much water through to the rad, and when moving that water gets cooled. End of.

    If the gauge goes up to 90 and stops when stationary, it will deffo be your thermo.
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  11. Welly
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    Welly VX220 SC Driver :)

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    [Feb 24, 2010]

    Not that I know of - but possibly. For example, would it limit boost when started cold - no. So I doubt it....
    #11
  12. will.f_1.8t
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    will.f_1.8t Member

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    [Feb 24, 2010]
    cheers welly! will the low temps have an affect on the performance/economy/engine wear? obviously the engine is set up to run at 90, so surely its not good, im not a mechanic but would be good to understand it a little more.
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  13. AudiiduA
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    AudiiduA Member

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    [Feb 24, 2010]
    I was told tonight the stats are plastic and get brittle with age and heat! the then start to break up inside the housing allowing too much water through the rad!
    This then will cause a small loss in mpg but no much! hope this helps us all? so basically the same as what welly was saying!:icon_thumright:
    #13
  14. feville
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    feville Frank

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    [Feb 24, 2010]
    Plastic?

    [​IMG]
    #14
  15. AudiiduA
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    AudiiduA Member

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    [Feb 24, 2010]
    Yep! not sure if plastic on every 1.8? and may have been on about the housing? the guy worked for VW/AUDI since he left school! im now thinking it may have been the sender? will ask him again Saturday! got me puzzled now as that pic is the same as the one i found!:unsure:
    #15
  16. feville
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    feville Frank

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    [Feb 24, 2010]
    Wish i had a VAG mechanic at my disposal lol!
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  17. steviet
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    steviet Member

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    [Feb 24, 2010]
    I would change thermo and cooltant temp sensor and dont forget to get G12 anti freeeze!!..Its the housing that is plastice dude.
    #17
  18. AudiiduA
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    AudiiduA Member

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    [Feb 24, 2010]
    LOL, not at my disposal at all, he is a pal of mine but still have to pay the man! having major service done with iridium tipped plugs also! so gonna cost me this weekend!:faint:
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  19. Welly
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    Welly VX220 SC Driver :)

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    [Feb 25, 2010]
    Thermo is deffo metal, 100,000%. lol.

    Running whilst down on temp will not adversely affect the engine at all - if anything it makes head gasket failure less likely. BUT it will run rich - resulting in power loss and poor fuel consumption. Thats really the only side effects....
    #19
  20. golf
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    golf ***** rent boy VCDS Map User

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    [Feb 25, 2010]
    Welly, you make it sound like the thermostat change is a simple job with your handy little guide up there, but I've been struggling to get that bastard bottom bolt off for two days now! Even with a universal joint and a long extension I just can't seem to get a good grip on it. I can change the turbo on my A4 in under three hours, but it's taken me two days to change a bloody 'stat, and I'm nowhere near closer to getting it sorted than when I first started!
    #20
  21. Welly
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    Welly VX220 SC Driver :)

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    [Feb 25, 2010]
    That's a bit of an arse dude, how come you're struggling to get it off so much? It's only a 10mm bolt so I wouldn't of thought it would of been in that well....?
    #21
  22. Matt82
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    Matt82 Active Member

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    [Feb 25, 2010]
    turbo off in under 3 hours? thats hardly pushing it. a mate of mine saw an R5GTT crash whilst having a race (R5GTT driving like an idiot)

    the R5 owner was given a kicking and knocked out. the turbo (hot) was stolen before the police turned up

    essex is fantastic
    Last edited: Feb 25, 2010
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  23. feville
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    feville Frank

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    [Feb 25, 2010]
    ???
    #23
  24. Matt82
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    Matt82 Active Member

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    [Feb 25, 2010]
    cant you read it?
    #24
  25. feville
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    feville Frank

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    [Feb 25, 2010]
    Just thought it was pretty random....

    Ah i see what you're talking about DUURRR!

    Thats a pretty good effort lol!!
    Last edited: Feb 25, 2010
    #25
  26. Welly
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    Welly VX220 SC Driver :)

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    [Feb 25, 2010]
    I couldn't either but it's OK not....

    I bet he was pissed right off!!
    #26
  27. Matt82
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    Matt82 Active Member

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    [Feb 25, 2010]
    he had been driving like a tool so by all accounts deserved the kicking and having his turbo nicked.
    #27
  28. Welly
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    Welly VX220 SC Driver :)

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    [Feb 25, 2010]
    Oh, well thats fair enough then. There are plenty of them round my way. And what is it about kiddies on bloody mopeds?
    #28
  29. Welly
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    Welly VX220 SC Driver :)

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    [Feb 25, 2010]
    The stock water pump impeller is plastic - maybe that's what he meant?
    #29
  30. feville
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    feville Frank

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    [Feb 27, 2010]
    Changed my thermostat this morning along with the coolant sender, job took all of 30-40mins and now my car comes upto 90 and stays there.

    The only thing i had to remove to get the lower bolt out with ease was the guide clip (8mm) for the cable coming off the alternator.

    All in all a productive morning :icon_thumright:
    #30
  31. AudiiduA
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    AudiiduA Member

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    [Feb 27, 2010]
    Hi, done mine too today! did it without taking off the alternater or even moving it! a bit fiddly but wasnt too bad, temp stays at 90 degrees now!
    i put new coil packs and iridium tipped plugs too, longlife 5-30 oil filter, airfilter,drained coolant and refilled with G12 antifreeze!:)
    #31
  32. Matt82
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    Matt82 Active Member

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    [Feb 27, 2010]
    feville, that 8mm nut is a must imo. well done on getting it sorted. now to plan the next job
    #32
  33. feville
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    feville Frank

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    [Feb 27, 2010]
    indeed, it seems neverending but i love it.

    Thinking silicone TIP next :cool:
    #33

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