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1.9 tdi coolant temp in cold weather - should it go up and down?

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by M7R, Dec 2, 2012.

  1. M7R
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    M7R Type Approval Engineer,

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    I picked up a 130 tdi yesterday, on the 120 mile trip home the coolant was sitting at about 85deg all the way home, with a temp of only 1deg or so out side and the inside temp set to 23deg, when I slowed down a bit the temp went up and nearly got to 90, then when sat at traffic lights the temp goes down again, once your moving and using throttle it goes back up...I first thought it could be the stat, but been out to Sheffield and back today in the wife's exeo, and that's only 5months old and 10k miles on it (b6 is a 05 plate and 95k with cam belt and water pump done 15k ago) and that seems to be doing the same so should I be looking to change the stat on my b6 or is it just that the interior heater is too efficent and is robbing all the engine heat? (I turned the heater to hi when sat in the wife's and managed to drag theatre temp down from 90 to about 80 in a few mins with a outside temp of 1deg)

    if this is normal that's fine... If not ill change the stat in mine to see if it fixes it..

    cheers

    karl
    #1
  2. Ste_Nova
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    Ste_Nova Active Member

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    lazy stat
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  3. Mike B
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    Mike B Member

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    A new genuine stat could help but why bother if its all OK?
    #3
  4. stu_m
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    stu_m Active Member

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    hows it all OK if the temp isn't reaching 90°c and staying there?

    once mine hits 90 it stays there all day no matter how fast or slow I drive and how hot I have the heating!

    as above sounds like a lazy stat I had one like it and the temp used to move about until I fit a genuine one
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  5. M7R
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    M7R Type Approval Engineer,

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    Ill order one from TPS tomorrow, going for some other bits anyways

    Ill borrow the wifes car one day for a run to work too, and see what that does as I will be peeved if thats got a lazy stat already!
    #5
  6. SL11CKK
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    SL11CKK Active Member

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    Its only yesterday I was wondering the same thing with mines too. And then I find this thread now. My one seems to never hit the 90 mark. Im going to change both the temp sender and the stat. I seem to only see between 20 and 35 average consumption which is the reason why I think something is wrong.

    Also the engine was shaking couple of days ago really bad @ idle so that could be the cause.
    #6
  7. demus
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    demus Fire in the hole !!

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    Defo stat stuck open slightly, with the high fuel pressures and atomisation of modern diesel engines, they will cool slightly from hot when idling. Mine done this a year or so ago, only really pulling its ears back would get it to 90 deg..
    #7
  8. 666markyboy
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    666markyboy Active Member

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    Really need to do mine aswell.... didn't get above 70deg this morning on the way into work and thats a 40 mile motorway drive
    #8
  9. SL11CKK
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    SL11CKK Active Member

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    Just read how piss easy it is to change the stat. Like changing the air filter out.....Just a bit messy cos of the water.
    #9
  10. stu_m
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    stu_m Active Member

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    yeah its pretty easy as long as your housing has the prongs to hold the stat

    If you read a haynes manual it says to place the stat in the block then the seal then the housing which in fact you put the seal on the housing then the stat it will only go on one way then you turn it 90° so the two prongs inside hold it on to the housing then you just pop in in the block

    when I first did mine the housing had the prongs missing and it was a right pig to do
    #10
  11. demus
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    demus Fire in the hole !!

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    Watch you don't drop any bolts, there is a casting underneath the stat bolted to the side of the engine with a slot in it, and guess what.. I dropped one, cock.
    Total arse to get out after 1/2 an hours fishing!
    #11
  12. stu_m
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    stu_m Active Member

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    I did that and also with the seal too!!
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  13. marktdisport
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    marktdisport Active Member

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    hows it ok if it's not running at 90 then the ecu could there for be altering the fuelling so if you like putting fuel in then its ok
    #13
  14. dale86
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    dale86 Member

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    This is great as mine was doing exactly the same today and will it effect fuel efficency ive filled my a4 up today from nearly empty to the brim and says om only gona get 320 miles out of a tank. Im sure it use to do about 420 to a full tank its a1.9tdi quattro.
    #14
  15. mattyb6
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    mattyb6 Active Member

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    How much is a genuine stat? And temp sender?
    I have same problem
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  16. M7R
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    M7R Type Approval Engineer,

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    This depends how you drive, and a full tank will always say you have way more for a short bit of economy driving, and an extra 4mpg is alot with a 12 gallon tank... vs a half full tank.

    I will know how much one is later so I will let you all know, (on my trip to work with a outside temp of 5deg I was still sitting at between 85 and about 89deg, but sat at the lights just outside work after a 30 mile drive, I put the heaters on full and it was warm but not hot... and I got the temp down to 75 in about a min! you could see the temp gauge moving!
    #16
  17. StuG808
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    StuG808 1.9tdi130 Avant FailWheelDrive

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    Have a look through the forum history, it happens to almost everybody and there's a couple of good threads showing photographs and things of how to replace it.

    Maybe there should be a sticky with common problems and links to the appropriate threads? It would be a good resource.


    Also, I couldnt care about replacing a thermostat with a genuine one. It seems that 'Audi' ones are failing across the board, so I'd rather pay 10% of the price on a so-called copy and take my chances! ;)
    #17
  18. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    #18
  19. StuG808
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    StuG808 1.9tdi130 Avant FailWheelDrive

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    Haha, whoops ;)
    #19
  20. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    Thats precisely the reason I haven't done much with it lately, people never look at the stickies, and always start a new thread anyway!

    [​IMG]
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  21. M7R
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    M7R Type Approval Engineer,

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    My local halfords didn't have one in stock and couldn't even order one... So I'm just going Tps as I know it will be correct
    #21
  22. stu_m
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    stu_m Active Member

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    Its about £20 for the stat with seal

    and about £30 for the temp sensor

    I fitted 2 cheap stats at £11 each before I bought a genuine one the two cheap ones where **** from the off!! so in my case it would have been cheaper to buy a genuine one in the first place
    #22
  23. Johnboymason
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    Johnboymason Member

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    i got mine from unipart hope its genuine lol
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  24. StuG808
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    StuG808 1.9tdi130 Avant FailWheelDrive

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    I got mine for £5.18 with seal, seems fine after 7k miles.
    #24
  25. Johnboymason
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    Johnboymason Member

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    after 7k :s
    #25
  26. SL11CKK
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    SL11CKK Active Member

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    Yep around £30 for the sensor and approx £20 for thermostat.

    I wonder if you do need to bleed afterwards though. Regardless I did bleed it for around 20 mins, but will bleed more tomorrow just to be on the safe side.
    #26
  27. M7R
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    M7R Type Approval Engineer,

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    New stat is £20 on trade bar a couple of pence, that's from Tps.

    Changed it in a out 30mins on the drive in the dark, lol dead easy! Will find out tomorrow if it works as old stat disnt look like it was stuck open when removed,
    #27

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