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Changing the thermostat, HOW???

Prawn Nov 25, 2007

  1. Prawn

    Prawn My other car is a MINI!!!!

    Evening guys,

    I did the brakes on my A3 today, then decided to have a go at changing the stat, to sort out my recent cold running issues.

    I'm fairly sure I have located it correctly, sitting just behind the alternator, clearly on view.

    But how the hell do i get to the lower allen bolt?

    I've tried all my tools with all sorts of extensions but I cant get anything onto the lower bolt without moving the alternator

    HTC seemed confident it could be done without touching the alternator though.

    I am clueless.

    If the alt does need to be moved, how do I do this? all systems I have worked on before have worked around the alternator pivoting to tension the belt, but this system appears to have a seperate tensioner :(

    Modern cars confuse me!

    Is this the water take off that the stat sits behind?

  2. RGS3

    RGS3 Member

  3. marms

    marms Member

    That link is for changing the Temp Sensor not the Thermostat so I don't think that is going to help Prawn. Good link all the same for those wanting to change the sensor which is a very common part to fail.

    Sorry Prawn, Not sure how you are going to get at that bolt. I assume the usual universal joint on an extention didn't get near it?
  4. S3 Jock

    S3 Jock Member

    RGS3 post is for the sensor so not applicable.

    To remove the alternator belt, the tensioner is a seperate pulley. You have to rotate either the pulley body by engagin on a lug, or in some cases teh central bolt of the pulley (ie teh one that holds the pulley onto the tensioner body) and rotating clockwise I think.

    Get it out of the way then you should see the bolts for the alternator. You may find you need to remove the alternator bracket too.


    Try and get in there with a hex bit, then use the ring part of a 10mm open ended spanner on the 'bit' and engage another spanner in the jaws of the 10mm spanner that's on the hex bit? You only need to move it a fraction to break the fasten, then it should be easy enough to turn.
  5. HTC

    HTC Active Member

    Yes that is the correct place.

    You should be able to get an allen key in the hole in the bolt head. I have also used a gooseneck rachet spanner for these occasions.

    To remove the alt, you remove the serpentine belt and then you should be able to see two large bolts on the belt side. I tried this first time I did a thermostat, but I couldn't get them loose. You may have better luck. Remember to disconnect the battery.
  6. rodenal

    rodenal Active Member

    Id try the bottom first as the alternator is a bast*rd to get to move
  7. RGS3

    RGS3 Member

    Sorry guys - my mistake, thought they were the same thing.
  8. S3 Dave

    S3 Dave Now running on Heavy Oil

    Did mine on the S3 and there was loads less space than that. Crack the hex head with a small ratchet and "knuckle joint" You can then get a ball ended allen key in! re-assembly is harder!! But not impossible!!
    Check other posts on here!! Search thermostat.

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