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CTS or Thermostat?

SunnyG Jul 18, 2012

  1. SunnyG

    SunnyG Member

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    Car doesn't warm up no mother how long you drive it its 1.9tdi 130 and it only just lifts off the bottom after a while, is that the CTS or thermostat?
     
  2. Nilz

    Nilz Defo worth the wait :) Team Ibis TFSI Owners Group quattro Audi A4 S-line owners group saloon Manual

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    I would say cts, worth doing that first as its cheaper and easier to replace.
     
  3. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    Its almost never the CTS.

    Change the Thermostat.

    CTS also isnt cheaper, its about 40quid, vs 10 or so for the stat.
     
  4. SunnyG

    SunnyG Member

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    Okay probably do both then i guess how shall i do a coolant flush as the orange stuff in their at the mo?
     
  5. Pops848

    Pops848 Active Member

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    I'd change thermostat - faulty CTS can also gives out cold / hot start issues. Changing the fluid is simple enough, drain it through the drain point, then fill up with coolant and bleed through until no air bubbles.
     
  6. SunnyG

    SunnyG Member

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    When you say bleed through? Can you elaborate
     
  7. Nilz

    Nilz Defo worth the wait :) Team Ibis TFSI Owners Group quattro Audi A4 S-line owners group saloon Manual

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    Oops sorry, got it the wrong way round!!! DOH!!!
     
  8. jamieA3

    jamieA3 Member

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    Well I have just gotten over this problem. a new thermostat cost me 5.49. sure its a cnut of a thing to get out as the housing is behind the alternator, but i am a utter noob and it took me half hour.

    i say change thermostat mate, they seem to be a problem on the cars. If your anywhere near hertfordshire ill do it with you if you like.

    EDIT.. have you checked the temp through the climate control ? hold recirc + ^ then select 49c, press recirc again and bingo it will show you the genuine accurate temperature. then you will know if its a sensor or thermo
     
    iucle likes this.
  9. SunnyG

    SunnyG Member

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    Yeah I'm a bit far mate near birmingham and ok i will do that what should i be looking for?
     
  10. jamieA3

    jamieA3 Member

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    Well if you have climate control, do as i said above while driving/at lights or whatever. if your needle is the same as what is says on the climate control then its the thermo.
    when you change the thermostat ( if u do ) youl need to do this **WHEN ENGINE IS COLD**
    1) take of engine cover + bracket thats attached to dipstick guide (holder)
    2) undo expansion tank cover to relieve pressure in system and the remove the coolant hose from the thermostat housing( just behind the dipstick to the left slightly. replace expansion tank cap and put the now leaking hose behind a hose to hold it upright.
    3) using a socket extension piece with a flexi end and a 10mm socket, remove the 2 bolts holding the thermostat housing to the engine ( very very tricky, heres when i broke dipstick guide)
    4) you will then see the thermostat *** take note of how its positioned and which side the seal is *** remove this and replace with new thermostat and seal
    5) replace housing, hose and make sure all is secure.
    6) with expansion tank OFF, start engine and look closely for leaks while reving the engine ( may need a friend with you ) and squeezing the hose you replaced. this will bleed the system of any air thats trapped.
    7) providing all is ok, there are no leaks, the temps gone up to 90 and all the air is out of the system, replace tank cover go for a test drive but not to far from home. inspect again for leaks. replace engine cover.

    job done. It sounds complicated, its not but it is very fiddly ! you will also need to top up the coolant if you lose a lot
    DO NOT MIX COOLANTS, if its pink stuff you have now ( g12) then only use pink stuff or it will curdle/blob up


    heres what you should have before starting.

    * thermostat with seal
    * coolant + water
    * socket set
    * pliers ( for hose clips )
    * flat head screw driver ( engine cover )
    *allen key set ( small bracket at front of dipstick )
    * new dipstick guide just encase ( you will break it 90 % sure )

    And most importantly, lots of patience


    hope this helps, sorry if its a bit long winded. I just would rather tell you myself than re direct you to a guide that someone else has written.
    I was very nervous about doing this job, I even started a thread asking people to help me ( thermostat help hertfordshire ) but once you do it you will feel great and thats one more thing you have learnt.

    all the best , jamie
     
    iucle likes this.
  11. Nilz

    Nilz Defo worth the wait :) Team Ibis TFSI Owners Group quattro Audi A4 S-line owners group saloon Manual

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    Whereabouts are you based Sunny??
     
  12. vfr800

    vfr800 Active Member Team Dolphin Grey Audi S3 quattro Audi A6

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    Just to reinforce what jamieA3 said:

    Get a new dipstick guide - it's only a few quid - and 98.9% it will break. If you break it put a glove over the snapped bit to stop coolant getting in.

    Flush and fill with new G12++ (the pink stuff).

    Note how the old stat. and seal is positioned and refit the same way.

    Oh and the coolant it nasty stuff - don't get any on you and wash spillages away with lots of water - take recovered coolant to the local tip.

    HTH Liam
     
  13. SunnyG

    SunnyG Member

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    Nilz im in wolverhampton, thats a really comprehensive guide thanks to all but to be honest i think that I'm just going to get it done when i service soon as i haven't got a socket set to hand.
     
  14. Nilz

    Nilz Defo worth the wait :) Team Ibis TFSI Owners Group quattro Audi A4 S-line owners group saloon Manual

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    LOL...after all that Sunny!! ;)

    If you do get it done, just get both CTS and Stat done at the same time.
     
  15. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    Why? Its almost never the CTS.

    Diagnose the problem correctly, and change the faulty part. You dont replace the light switch, fuses and every bulb in the car when you pop a sidelight do you?

    Symptoms of a CTS are totally different to the symptoms of a faulty thermostat.
     
    TurboLover and mikedom78 like this.
  16. Nilz

    Nilz Defo worth the wait :) Team Ibis TFSI Owners Group quattro Audi A4 S-line owners group saloon Manual

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    I had both go on my old A4, so it could be that, but as said get it diagnosed correctly and who knows you may be ~£40 better off if it is just the Stat :)
     
  17. SunnyG

    SunnyG Member

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    Had VAG mechanic come down today warmed the car thoroughly had a look over to check the issue, checked CTS temp was fine and working, checked thermostat and both coolant hoses were working he showed both with flow once car warmed up, but doesn't understand why recirc and ^ at 49 degrees came up with 30 degrees? anyone understand and care to think why? also saw the issue as not thermostat or cts but the instrument panel being faulty.
     
  18. SunnyG

    SunnyG Member

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    ??? anyone
     
  19. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    are you saying that channel 49 on the climate only ever showed 30c?

    Could well be the CTS, but you need to do some proper diagnostics, leaving a diesel idling for a long time is pointless as they run so cool.

    Heres what to do. Get channel 49 up on the climate, and go DRIVE the car. If you have vagcom then connect that and get it to display the coolant temp from the Engine controller as well so you can compare them. Dont go onto a motorway, or any other fast roads, find somewhere around town where your constantly accellerating and braking, so you can get some heat into the system, and keep an eye on the climate display.

    If it just sits at 30c and never moves, then the CTS is likely faulty.

    If it starts to climb (even if it doesnt actually get to 90) then make your way to a faster road, and sit cruising at 50-60mph and see what it does, if it drops back down again, then your thermostat is the likely culprit.
     
    iucle likes this.
  20. SunnyG

    SunnyG Member

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    Climate only shows 30 once showed 23 rising to 30 on a start up, i haventgot vag com but when the car was on the diagnostic he said the cts was showing 120 something which was normal. So i think its best to do the cts anyway cars getting serviced next week too? Any dangers of driving the car as it is? Effects of driving the car under boost?
     
  21. SunnyG

    SunnyG Member

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    Did the drive sat at 30 the whole time going to replace cts can anybody elaborate on the above questions?
     
  22. iucle

    iucle Member

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    Hey, just read this thread.
    In my a4b7 1.9tdi the water temperature fluctuates depending if on motorway or not. If in town, 80-90ºC, If motorway, goes down to 70-75ºC. Does it mean that is the thermostat? Its been doing it for a while and never took it in consideration. Then yesterday the car was blowing warmish air on the motorway with the clima up to high.
    Do you think it can be the thermostat? CTS? or the heater matrix?

    Cheers.
     
  23. Monkeyboy76

    Monkeyboy76 Member

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    I'm also have similar problems, excuse my ignorance but what is the Cts, haven't quite got the lingo yet
     
  24. iucle

    iucle Member

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    It is the coolant temperature sensor "cts" don't know what's the problem 100% in my case. Will try to flush the heater matrix tomorrow and see if it helps.what is your problem?
     
  25. Monkeyboy76

    Monkeyboy76 Member

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    Temp gauge seems to be taking forever to get up to 90. Only noticed on my way home from buying it yesterday. Was giving it some on the motorway but looked like it was only going up to about 70ish
     
  26. iucle

    iucle Member

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    Same mine.
    Everyone says it is the thermostat. What it actually does it has to keep the car at 90°C once the engine is hot. It doesn't matter if it is cold outside or not. It receculates the hot water. If it doesn't do that, it means the thermostat is gone.
    £15 for the part of you know how to fit it.
    It is on my list after the flushing.
     
  27. Monkeyboy76

    Monkeyboy76 Member

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    Cant moan at 15 quid and I'll do it meself. I know me way round a socket set so should be ok
    I might replace both, just to be sure
     
    iucle likes this.
  28. Monkeyboy76

    Monkeyboy76 Member

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    So, been for a decent drive round tonite and temp gauge was between 50/70 and seemed to dip a little when I gave it some. Temp gauge will rise to 90 when its stood still on idle.
    Are we still thinking thermo
     
  29. iucle

    iucle Member

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    I would still day is the stat:
    If the stat is goosed the engine will never get up to temperature as the stat isn't shut when it should be, to give the water time inside the block time heat up more. Therefore when driving in cold weather the water is cooling down again before it can get hot as it's circulating straight out of the block to the radiator and back again.....yet when you're in the city driving slowly or stationary the water isn't being circulated as fast through the system and has a little more time to get a little extra heat
     
  30. Monkeyboy76

    Monkeyboy76 Member

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    I'll get one ordered then
     
  31. Monkeyboy76

    Monkeyboy76 Member

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    Where's best place to get a thermostat. Cheapest I can find is around 35 quid
     
  32. iucle

    iucle Member

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    Eurocarparts about £8
    Car parts 4less about £3 if you have time to wait.
    By the way, did mine today and it solved the problem.
    Water goes up to 90 and stays there.
     
  33. Monkeyboy76

    Monkeyboy76 Member

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    Is that the same prices for petrol and diesel as mines 2.0 tfsi
     
  34. iucle

    iucle Member

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    If you go on Eurocarparts you'll be able to put your reg Nr and find out how much does it cost for your car
     
  35. Rainbird

    Rainbird Active Member

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    CarParts4Less = EuroCarParts, but with slightly discounted prices. If you can find an ECP discount code then it's generally the way to go but if ECP & GSF are full price then CP4L are usually worth a check :)
     
  36. Monkeyboy76

    Monkeyboy76 Member

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    I'll try them now as everywhere else seems to be out of stock
     
  37. Monkeyboy76

    Monkeyboy76 Member

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    They are also out of stock for bwa engine code
     

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