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1.9 Running cool after CTS & Stat change

Reub Oct 26, 2020

  1. Reub

    Reub New Member

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    Hey, first of all, I know running cool is a very common issue and has been posted about hundreds of times, however, I have just changed the coolant temp. sensor and the thermostat with genuine parts and there's no change. I can't find any info on the forum on what to do from here.

    Today I changed the 2 parts and thrashed the car up the road for about 20 minutes and it barely made it above 70. I then drove home in a more relaxed manner and the temp dropped below 70 again. I felt the thermostat housing with my hand after this and it felt warm, but a long way off how warm the other coolant hoses were.

    I currently get about 600 miles to a tank or about 38 MPG.

    Does anyone know what I can do from here?
     
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  3. Cobra88

    Cobra88 Registered User

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    genuine stat ?
    correct part for your engine code ?
    no idea what your car is or how old it is so pointless figures for now.

    if its petrol its doing good mpg
    if its diesel your getting 8mpg worse than me on 130 tdi AVF code 6 speed manual
    my average non motorway early morning town no traffic mpg is 45.6
    my motorway steady 70-80 is 52.2 or thereabouts.
    should reach 90 degrees in about 3 miles at moment (Mine does)

    you've either fitted a Chinese stat or you have wrong stat for your engine code or you did sommat wrong ;)
     
  4. Gazwould

    Gazwould Registered User

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    I put up with a slow thermostat for years until it was going to hamper the mot smoke opacity plate value test , 3.00 was previously allowed , now it would be 0.60 !!!

    2019-11-23 05.22.28.jpg



    Can't believe how quick it now gets up to 90° .
     
  5. Reub

    Reub New Member

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    What did you change??
     
  6. Reub

    Reub New Member

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    I'll double check the codes now. Sorry, forgot to say, 2003 A4 B6 1.9 TDI 130 AWX 5 speed.
    Since the post yesterday, I bled the cooling system, following the guide in my Haynes manual. I then drove 8 miles and the gauge just barely lifted off the 50. Still confused.
     
  7. Cobra88

    Cobra88 Registered User

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    Hi Reub

    Pretty much the same as my AVF but with the smaller clutch so i would think you should get the same MPG as me unless you have a lead foot.:)
     
  8. Cobra88

    Cobra88 Registered User

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    might be worth changing the CTS (coolant temperature sensor)
    one of them send temp to ecu the other sends temp to gauge (I think but mine has always worked ok)
     
  9. Reub

    Reub New Member

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    As far as I can tell, my car only has one CTS and I've already changed it.
     
  10. Cobra88

    Cobra88 Registered User

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    was it genuine ? (Sorry missed CTS in title)
     
  11. Reub

    Reub New Member

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    It's a Febi Bilstein 059 919 501 A S1. The thermostat is a MotoRad 270-88K. MotoRad list this thermostat as being for Ford or Mazda but it looked the same as the one that was in my A4 already and the temperature on it was 87 C which is correct. Maybe I need a different one though.

    When people say genuine do they mean Audi parts? I got these from my local motor factors, they have always given me good parts in the past.

    How do I find the part numbers of the original Audi parts to check against these parts I have? Or is there another way to check compatibility just using the part numbers I have?
     
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  13. Cobra88

    Cobra88 Registered User

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    let me have your year and model info and ill look up part number
     
  14. Reub

    Reub New Member

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    I think I gave you everything I know already, 2003 A4 B6 1.9 TDI 130 AWX 5 speed saloon. Do you need more info? Can't think of anything else helpful haha.
     
  15. Cobra88

    Cobra88 Registered User

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    Last edited: Oct 27, 2020
  16. Reub

    Reub New Member

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    What do I do with this info? I have no idea how to find parts properly.

    Also what is ekta?
     
  17. Cobra88

    Cobra88 Registered User

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    sorry ETKA

    its the system they used to use at Audi dealerships. (I think)

    the code is the part number you need for correct thermostat
     
  18. Cobra88

    Cobra88 Registered User

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    Last edited: Oct 27, 2020
  19. stevey83

    stevey83 Registered User

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    Could also be a failing or knackered waterpump.
     
  20. Cobra88

    Cobra88 Registered User

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    usually failing water pump will overheat as soon as you get to speed but be fine on idle (plastic impeller slipping in shaft) but they should have been replaced long ago.

    or did i dream it?
     
  21. stevey83

    stevey83 Registered User

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    Yeah forget what i said, it would be the problem for overheating!
     
  22. Cobra88

    Cobra88 Registered User

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    it was a good call and i get it wrong reasonably often ;)
     
  23. Reub

    Reub New Member

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    I've ordered a genuine thermostat from Audi to see if that'll solve the problem. Does anyone know which way through the radiator the coolant flows? I checked the coolant hoses when the engine was at roughly 60 C and the top hose from the rad was fairly hot, the bottom one from the thermostat housing was warm but not as hot as the top one. Since the bottom hose was warm does this mean the thermostat is open?
     
  24. Cobra88

    Cobra88 Registered User

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    Hi Reub

    Cant find a diagram showing which way the coolant flows.

    I would expect the top hose to get hot first if you don't have an airlock.

    is the coolant level in the tank staying still from cold to hot ?
    should be level with the join in the tank both hot and cold if no air is trapped anywhere in the block or the HVAC system.

    Rick
     
  25. Cobra88

    Cobra88 Registered User

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    is there still a link on here to the full workshop manual for the B6/B7 i uploaded a few years ago ?

    or is it allowed now ?
     
  26. Reub

    Reub New Member

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    Yes, stays level cold or hot I believe, or it changes its so small I haven't noticed. If the coolant hoses to and from the rad are warm at all then does that mean coolant is flowing to the rad and therefor the thermostat is open? The radiator was warm to the touch as well by the way.
     
  27. Cobra88

    Cobra88 Registered User

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    ok sounds like you don't have any air trapped in the system.

    its either the new cts not reading correctly or the new thermostat not opening/closing at correct temperature.

    Rick
     
  28. Cobra88

    Cobra88 Registered User

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  29. Cobra88

    Cobra88 Registered User

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    god knows how i quoted myself!
     
  30. Reub

    Reub New Member

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    Thanks, I ordered the thermostat from Audi but didn't order the CTS yet, I'll see if the thermostat fixes it first. The Audi thermostat alone cost more than the other thermostat and CTS combined. :weary:
     
  31. Cobra88

    Cobra88 Registered User

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    No worries Reub

    most other stuff is fine
    yep try Stat first.

    i would suspect stat is the problem.
    Rick
     
  32. Cobra88

    Cobra88 Registered User

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    just spent 3 hours cleaning my Avant now its ******* down again :(
     
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  34. stevey83

    stevey83 Registered User

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    You could have tried running the car no thermostat to see if that ruled the thermostat out.
     
  35. Reub

    Reub New Member

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    How would that help? It's running cold, not hot. Taking the thermostat out will do nothing surely?
     
  36. Cobra88

    Cobra88 Registered User

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    exactly ;) but would be a good idea if it was running hot
     
  37. stevey83

    stevey83 Registered User

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    Sorry men my heads in the shed! God knows why i posted that! Ill keep shut from now on, hopefully your new stat will sort it out!
     
  38. Cobra88

    Cobra88 Registered User

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    Dont be daft stevey
    Alway worth a punt
    If people dont post nowt gets fixed ;)
     
  39. Mike B

    Mike B Registered User

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    Although taking the stat out could help if it showed no difference which would indicate that it wasnt working at all or not closing shut tight.On the other hand if it ran even colder then the stat would be doing something.I have tried dangling a stat in water and watching as its heated to boiling which does give some indication of its function but the best plan would be to fit a genuine one .Another crude ploy is to blank off a lot but not all of the rad and see if it runs hotter.This used to be common many years ago when stats were very much more unreliable and heaters almost useless but it was only for the dedicated and could catch you out badly cos most cars didnt have a gauge!
     

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