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Poor MPG Audi a4 1.9 TDI 130 BHP Sports 2004 / thermostat??!

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Sam84, Feb 8, 2012.

  1. StuG808
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    StuG808 1.9tdi130 Avant FailWheelDrive

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    [Feb 21, 2012]
    I'll be fitting a new thermostat tomorrow night as well as giving a general service, so will report back on temp gauge and mpg readings (currently temp is just over or at 70, and trip calc mpg is 40.2mpg).

    Haynes reckons the thermostat is a tricky job with intake manifold and alternator removal, but I've read on forums that people have managed to do it with just removing the alternator, or even removing neither.
    #41
  2. stu_m
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    stu_m Active Member VCDS Map User

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    [Feb 21, 2012]
    I did mine without removing either but is a bit tricky

    It could also depend on engine code too mines an AVB which is the 100bhp one
    #42
  3. flearmonth
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    flearmonth New Member

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    [Feb 21, 2012]
    Any chance you can put a guide up on how to do if you manage it successfully? Also need to do the thermostat and planning to tackle myself to save money if not too difficult
    #43
  4. BlackQuat
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    BlackQuat Well-Known Member VCDS Map User

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    [Feb 21, 2012]
    I've just done the thermostat on our A6 tonight.
    Very easy job. I popped off the intake for abit of ease of moving really.
    It removes very easily, clip on the intercooler side and a jubilie style clip on the other side. Pop off the map sensor plug and it'll pull out.
    2 x 10mm bolts hold in the thermostat housing, just pull it away and to the side slightly and it comes away. Remember how the thermostat is sat in the block as it helps. Fit the new one in the same way as you saw the old one. Refit is reverse of removal really.
    Easy stuff lads!
    #44
  5. scottshere
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    scottshere Member

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    [Feb 24, 2012]
    Had the Thermostat changed today... Result !! Now it reaches 90 and stays there
    Would have taken a few pics of it being done, but to be honest you would not have seen much
    Didnt remove anything other than the 2 bolts and it was a simple swap over of thermostat and O ring seal
    Top up with the old pink stuff and job done
    £10 lighter at my local garage (sounded like an offer i could not refuse)

    Have noticed the car feels better/smoother (slightly)
    Now to see if the MPG is any different

    I am jinxed though, had this done and my dipped beam bulb went (only around 3 months old)

    Had my brakes and disks all round changed, front offside wheel bearing is now humming

    Hmmmm next......
    Last edited: Feb 24, 2012
    #45
  6. Sam84
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    Sam84 New Member

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    [Feb 25, 2012]
    Hope mine will just be the thermostat too, report back with the MPG :) What MPG were you getting before? Mine idles well but does seem to have a slight judder at times, wonder if it's due to this?
    Also what is the optimum revs to get the whole 130bhp/ max torque out of this engine before shifting? i'm guessing around 3800/4000 rpm?
    #46
  7. benjie
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    benjie Active Member

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    [Feb 25, 2012]
    I believe max torque comes in at 1900rpm and stays to just under 4000rpm. A slight judder at idle wouldn't be due to the thermostat.
    #47
  8. Sam84
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    Sam84 New Member

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    [Feb 27, 2012]
    any ideas what might cause a slight judder? it's spot on idle rev's around 900rpm, and doesnt move, sure it's not as its running rich due to the thermostat? I'll ask the guys tomorrow as it's booked in for it's thermostat change tomorrow finally
    #48
  9. marktdisport
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    marktdisport Active Member

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    [Feb 28, 2012]
    i get a dodgy shake on my tick over on supermarket fuels then a tub or forte injector cleaner and refill at a decent garage does the trick
    #49
  10. scottshere
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    scottshere Member

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    [Feb 29, 2012]
    MPG was at around 40/41
    Thats A and B roads with the odd blast between junctions on the motorway from time to time

    Not sure what im getting yet as i will check once i fill the tank up
    (plus got another trip to Birmingham and that should rack up a higher MPG, so will check after that)

    I have a slight judder too, but i recon its my DMF
    When i save the sheckles up, i'll get it changed
    #50
  11. Sam84
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    Sam84 New Member

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    [Mar 1, 2012]
    So i've had my thermostat replaced, this was the culprit for the Poor MPG / never reaching 90 degrees engine temp whilst driving. Coolant sensor was OK and didn't fluctuate.

    MPG readings i'll update in a day or two, it seems to be a bit better, especially the Miles To Go looks promising, used to get 140 miles to go with 10 litres, did it half hour after new thermostat it went up to 200 after fill up. but on this run looks like i'll get 43/44 mpg, with short motorways/ B roads/ bit of town, which I think is about right.
    #51
  12. Sam84
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    Sam84 New Member

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    [Mar 1, 2012]
    I have a slight judder too, but i recon its my DMF
    When i save the sheckles up, i'll get it changed[/QUOTE]


    I've put in some premium shell stuff, the expensive performance diesel is this a bad idea for TDI? does it affect MPG?
    What's DMF stand for and what does it do? for the newbie ?! ( me )
    #52
  13. scottshere
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    scottshere Member

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    [Mar 1, 2012]

    I've put in some premium shell stuff, the expensive performance diesel is this a bad idea for TDI? does it affect MPG?
    What's DMF stand for and what does it do? for the newbie ?! ( me )[/QUOTE]

    DMF - Dual Mass Flywheel

    You shouldnt have any issues with the Shell stuff, many believe its actually better
    Ive never seen any where selling performance diesel, just the normal run of the mill stuff
    (is it labeled as high performance?)
    #53
  14. Sam84
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    Sam84 New Member

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    [Mar 1, 2012]
    Think it's called V-power from Shell,- I usually use bog standard diesel from usual supermarket stations thus the ignorance when it comes to premium diesel names. Onto the slight judder again- Might give Forte injection cleaner a try, but then again my EGR is leaking oil a bit, had it cleaned on the outside, i just read in a post about a shuddering valve rubber thing inside and they can crack, and this might relate to mine who knows, or even yours? Or is your EGR fine?
    I'm a bit afraid when it comes to using injector cleaning liquids, my gf's dad did this on a 97 corsa 1.7D and it truly f*-*ed it right up made it worse than ever, had black smoke out of maifolds / exhaust /everywhere, did have 212 k on clock tho.
    #54
  15. scottshere
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    scottshere Member

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    [Mar 2, 2012]
    My EGR or something in that area is leaking quite a lot of oil
    A job im going to do/look at when i get a day off where the weather is decent

    Take the EGR off and give it a good clean (it is already blanked off at the exaust) change all the vaccum pipe with new that i bought from ebay (3mm black rubber pipe that i hope will do the job)
    Clean up the whole area with some sort of detergent so i can see if ive fixed it or not
    #55
  16. VTEC_Killer
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    VTEC_Killer Member

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    [Mar 8, 2012]
    I just replaced my coolant sensor but the temp gauge still remains at 70c so I'm guessing I need to change the Thermostat.

    So guys, can someone tell me the following please?

    - Where is the Thermostate located? (Pictures would be ideal - I have a 1.9 TDi 2004)
    - What parts will I need (i.e. Thermostate sensor, O'Ring etc) and how much will it cost?

    I'll do a write up for the forum if I can successfully change mine; thanks guys

    Thanks in advance.
    #56
  17. StuG808
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    StuG808 1.9tdi130 Avant FailWheelDrive

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  18. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Mar 8, 2012]
    If you can wade through all the BS......

    And a guide would be great :thumbsup:
    #58
  19. VTEC_Killer
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    VTEC_Killer Member

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    [Mar 13, 2012]
    I've read that the Thermostat can only be replaced when the timing belt is off and then the above posts says that it is behind the alternator!

    I'm a little confused!

    Can anyone confirm? I have a B6 2004 1.9TDI

    Thanks
    #59
  20. marktdisport
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    marktdisport Active Member

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    [Mar 13, 2012]
    can be done with alternator on ive been told also its a easy job and who ever told you the cambelts gotta come off !!! well dont let them near your car
    #60
  21. stu_m
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    stu_m Active Member VCDS Map User

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    [Mar 13, 2012]
    whoever told you that will be on about the water pump

    the stat is behind the alternator
    #61
  22. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Mar 13, 2012]
    Thats the case on the 2.5TDi's, maybe that's what you're thinking of.
    #62
  23. benjie
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    benjie Active Member

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    [Mar 13, 2012]
    It's easy. It's behind the alternator as said. 2 bolt and the pipe comes off, take note of the way the thermostat comes out (and the rubber seal) then put the new one in the same way. You need to do it when the engine is totally cold as you will lose some coolant - I lost about a 1.5L I think. After refitting, I topped up the reservoir. Bear in mind though that a day later I had a 'Stop Coolant' warning on the DIS - I was expecting this as I thought there would be a small air pocket that would have to work its way back to the reservoir.. which then made it drop sufficiently to set off the warning.

    Here's a picture of the location... (taken from front-left wheel looking into the engine bay).

    [​IMG]
    #63
  24. VTEC_Killer
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    VTEC_Killer Member

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    [Mar 14, 2012]
    Excellent - thanks Benjie; going to give it a crack this weekend.

    :)
    #64
  25. benjie
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    benjie Active Member

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    [Mar 14, 2012]
    My pleasure - good luck. My be prudent to get a spare bolt or 2 as if you drop one, it's likely gone forever!
    #65
  26. VTEC_Killer
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    VTEC_Killer Member

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    [Mar 15, 2012]
    It's funny you should mention that.

    When I changed the Coolant sensor, the metal ring that holds the black pipe to the EGR fell into the engine bay when I unclipped it with pliers.

    I thought it would drop on the floor but then realised the damn thing was sitting on the heat tray which I couldn’t see but could hear when I went underneath and flicked the tray.

    So I had to take the whole 2 piece tray off to get the damn ring - it wasn't too difficult but just awkward. I had never taken it off before so was a little apprehensive.

    Added 45 mins to the job!

    Word of advice to fellow members, the tray is in 2 pieces, you need to unscrew the further in one first before unscrewing the one under the engine bay (the overlap each other so one can't be taken off without the other).
    #66
  27. L7AUDI
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    L7AUDI Member

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    [Mar 18, 2012]
    Umm think i might need to change Thermostat too, car's temp has gone from sitting at a constant dead 90 down to 70 and every now and again 80 ish, I needed a water pump so thought that it might be better after that. Had the WP Cambelt & alternator pully all done but the car still has low temp whatever driving I'm doing allways struggling to get near 40mpg even on a nice long run :ermm: but I'm not sure what it should be doing in reality as it's a 1.9tdi quattro i know that the quattro knocks the mpg back...but i couldn't live without it lol
    #67
  28. VTEC_Killer
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    VTEC_Killer Member

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    [Mar 19, 2012]
    I changed mine over at the weekend, took me slighlty longer than I intended as I lost one of the screws so had to go and source another one from a local garage.

    L7Audi - I initially changed my coolant sensor first which didn't help the temp guage but now after changing the Thermostat, everything is working as normal :)

    I lost quite alot of fluid and had to use up a 1.5 ltr coolant and water to top it back up again.
    #68
  29. L7AUDI
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    L7AUDI Member

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    [Mar 19, 2012]
    I have a bosch approved garage within sight of my unit, I think I feel a lazy spell coming on lol :undwech:
    #69
  30. andythompson
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    andythompson New Member

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    [Dec 28, 2013]
    mine was exactly the same, (thermostat stuck open) change the thermostat but watch your water pump seals for leaking once changed!
    #70
  31. DieselJake
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    DieselJake God Mode

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    [Dec 28, 2013]
    Revived from the dead :keule: erm... well... welcome to the forum.
    #71

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