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Inexplicable coolant loss???

AR-rkon Aug 7, 2011

  1. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    Im losing coolant from somewhere (fill it on Mon morning, by the end of the week it's down to min. Has dropped so far at occasionally that the DIS warning comes on).... no idea where to start looking though.
    • HVAC works great hot and cold.
    • Coolant temp never above 90, and doesnt move...
    • No apparent leaks
    • No white smoke/steam
    :think: any suggestions where to start looking?

    Car is a 1.8T APU, and G12 is getting expensive with the amount ive gone through :(

    (on a side note also, how much oil should a 1.8T go through/lose?)
     
  2. Oranoco

    Oranoco Well-Known Member

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    Check the plastic pipe at the back of the engine and for signs of leaking on top of the gearbox
     
  3. ScottD3

    ScottD3 I want your faulty electronics Supporter Team V6 quattro Audi A8 Audi S8 Team Akoya TDi saloon

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    How's your carpets?
     
  4. B5NUT

    B5NUT Well-Known Member VCDS Map User quattro Audi A6 Audi Avant Owner Group S-line owners group s tronic

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    Have you checked the expansion tank overflow? I had the similar fault on my TDi and it turned out to be he head gasket, exaust gasses going into the coolant system and it was being chuck out the expansion tank.
     
  5. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    Carpets, bone dry. Gearbox was out only a few weeks back to do the clutch conversion, no obvious signs on or around that. Expansion tank "overflow" I've not looked at, will check that when I get a chance. Though the header doesn't smell "exhausty" even after a thrashing, just smells of g12 lol
     
  6. Bradderz_1988

    Bradderz_1988 Dont replace it, Upgrade it !!

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    Easy way to check is get someone to use an emissions tester over the header tank that will rule out the headgasket.
     
  7. THE MONSTER

    THE MONSTER Member

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    I presume you have your under tray on have you checked to see if that is full of water or any water in it lowest point and all that..

    That amount must be visible and going somewhere..
     
  8. Bradderz_1988

    Bradderz_1988 Dont replace it, Upgrade it !!

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    Also check for a pink crusty residue of coolant on the system also near the water pump and at the oil cooler pipes !
     
  9. Sandip

    Sandip Well-Known Member Team Nogaro Blue

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    I had this on my S3, put some red food colouring into your coolant, go for a drive, then pull you plugs out one at a time. If the ceramic on any of the plugs has turned pink then you may possibly have a hairline crack on the cylinder head.

    Or like Bradderz says, hydrocarbon test the coolant
     
  10. salad.dodger

    salad.dodger Member

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    I had coolant lose on a 5 series BMW, works out the head was leaking right at the back, could see water marks
     
  11. B5NUT

    B5NUT Well-Known Member VCDS Map User quattro Audi A6 Audi Avant Owner Group S-line owners group s tronic

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    A very easy test to check if your getting exhaust gasses into the coolant system would be to take it for a quick drive and get the engine almost upto temp and check the hoses for pressure, if they are solid then gasses are getting into the coolant system, and you are looking at either a HG failure or damage to the cylinder head.

    The top water hose on my car was just about solid even after a quick drive and the engine was around 80 on temp.

    One other possible cause is the expension cap has failed and needs to be replaced, a quick pressure test would answer that question or just get one from a breakers for a couple of quid.
     
  12. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    Ah well i have just squeezed the hoses and they are still quite soft :) so hopefully not a HG problem
     
  13. tdia4

    tdia4 TDIPOWARRR

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    Leaking from a Core plug maybe?
     
  14. Mike B

    Mike B Well-Known Member

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    Take off the header tank and check at the back for acrack.This is where we found a leak and the new tank was £12
     
  15. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    How do you mean a "core plug" ?
     
  16. ScottD3

    ScottD3 I want your faulty electronics Supporter Team V6 quattro Audi A8 Audi S8 Team Akoya TDi saloon

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    Round metal disk pushed in to the side of the engine. It Blocks up the old holes used during the manufacturing process.
    They can become thin and leak (happened on my land rover) or fall out.
     
  17. bmarshall

    bmarshall Member

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    Welsh plug
     
  18. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    After having a good look, i may have found the issue...

    Take a peek at the pics on FLICKR and tell me what you think... its like a pinky white sticky paste.... could be some coolant residue?

    Cheers guys...
     
  19. ScottD3

    ScottD3 I want your faulty electronics Supporter Team V6 quattro Audi A8 Audi S8 Team Akoya TDi saloon

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    Yup, I'd say thats coolant.
     
  20. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    thought so... have added a diagram of the area with positions i think the leak may be coming from... any ideas? I suspect No 3 is at fault... or hopefully duff pipes...
     
    Last edited: Aug 16, 2011
  21. ScottD3

    ScottD3 I want your faulty electronics Supporter Team V6 quattro Audi A8 Audi S8 Team Akoya TDi saloon

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    it looks like its coming from coolant pipes on number 14 of your diagram.
    Possible a split pipe or the metal pipe work in side has rotted away.

    I'd take the coolant pipes off, give the area a good old clean, replace the spring clips and try again.
     
  22. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    yup was thinkin that... Cheap fixes win :w00t:
     
  23. ScottD3

    ScottD3 I want your faulty electronics Supporter Team V6 quattro Audi A8 Audi S8 Team Akoya TDi saloon

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    Deffo.

    I just need to find out where my coolant smell is coming from now.
    I'm off to check my oil filter housing.
     
  24. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    if its strong interior smell. could be the HVAC exchanger.
     
  25. ScottD3

    ScottD3 I want your faulty electronics Supporter Team V6 quattro Audi A8 Audi S8 Team Akoya TDi saloon

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    I do hope you don't mean this
    [​IMG]
     
  26. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    yep thats what i meant... is that pic yours???
     
  27. ScottD3

    ScottD3 I want your faulty electronics Supporter Team V6 quattro Audi A8 Audi S8 Team Akoya TDi saloon

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    Nahh Google image.
    I hope its not.
    I really don't want to take my days out.
     
  28. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    Days? Did you mean dash??? Haha
     
  29. ScottD3

    ScottD3 I want your faulty electronics Supporter Team V6 quattro Audi A8 Audi S8 Team Akoya TDi saloon

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    LOL.
    Yeah Dash.

    The fact that it only smells when it pumps out warm air has me even more worried now.

    Know of any other way to check it?
    All my carpets are dry.
     
  30. AR-rkon

    AR-rkon Mod back in a "B" Staff Member Moderator Regional Rep Team V6 Team Silver Audi A6 Audi A4 Audi Avant Owner Group

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    Pressure test maybe?
     

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