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a4 problem

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by bowen, Jun 2, 2011.

  1. bowen
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    bowen Member

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    Hi guys,

    another problem, the temp gauge sometimes goes up sometimes is doesnt and the last two days the heaters have been cold. First place to start anyone?

    anyone got a part number/ price for the temp sender?

    thanks,

    Bowen
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  2. simon.m
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    simon.m Active Member

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    temp sensor is the best place to start and the thromastat i think they are both in the same place so do them both you should get chang from £40 for the both if i rember right
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  3. bowen
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    bowen Member

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    thought so, i had so many problems with my diesel golf which started of with the same problem.........
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  4. S3 GAZ
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    S3 GAZ Member

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    I'd start with temp sensor and thermostat replacement. I had the very same prob on my mk4 golf. I had no heating when I bought it. When I went to replace the stat there wasn't one there lol.

    If they don't make any difference I'd look at possible water pump failure
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  5. a4 cabrio
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    a4 cabrio Member

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    i had that with a golf as well, and the exact same thing when i took it to the garage, they said there was no stat, even though one was supposed to have been replaced a few weeks before.

    is it possible for a stat to fall out????
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  6. S3 GAZ
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    S3 GAZ Member

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    No there's no where for it to go unless it disintegrated. I think if the stat sticks shut and say the AA are called they remove the stat at the roadside to enable the car to be driven home and some owners don't replace it lol. Which is what i suspect happened in my case.
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  7. bowen
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    bowen Member

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    ordered a temp sensor. Looked last night to see how hard it would be to replace, but i cant see it?! the temp sensor on a 1.8t where is it?

    Thanks,
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  8. Avanti
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    Avanti New Member

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    i think its a green coloured plug, look at your lower engine cover and the top right hand screw that holds this down its sits just under there i believe, Unplug the wiring loom from the sensor, check you have the same colour/pin type. There are spade fitment (blue) and pin fitment (green).

    To the right of the sensor housing you will see a clip, pull this to the right, it may be tight, but should pop off. Its advisable to buy a spare while you get the part, they cost 40p and could save you a head ache. Tug on the sensor, it should pop out spilling minimal coolant in the process.

    Take your new sensor and rubber compression ring, push it back into the housing, whilst keeping downward pressure applied, push the clip back in, taking care to insert it into the gap provided, this should hold the sensor snuggly in place and stop it popping back out. If you can tug it out, you've done something wrong.
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  9. Jama665
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    Jama665 Member

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    Had this on mine when i brought it, Sensor had snapped and long with the housing to hold it in place. So i brought a new thermostat housing from audi comes with a new thermostat and sensor. Cost me sixty odd quid.
    But i found when i removed the housing on my car the old themostat was loose as the plastic retainers had broken, effectively making it useless. So im glad a spent a little more and got the housing.
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  10. S3 GAZ
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    S3 GAZ Member

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    If your heaters arent working I'd be more inclined to be replacing the thermostat. If it's stuck open the water will be constantly circulating round the radiator and the engine never reaches operating temp. So the temp sensor will not register a reading.
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  11. murran
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    murran Active Member

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    the thermostat is in the housing under the inlet manifold towards the front of the engine (under and slightly behind the alternator). the coolant temp sensor is in the housing on the back of the head.

    if your changing the thermostat then you can check the plastic impeller on the water pump at the same time. with the thermostat out you can put your fingers in the hole, you can feel the impeller. if its loose or you can turn it, then its parted company.
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  12. Jama665
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    Jama665 Member

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    I was led to believe the temp sensor on the thermostat housing was the sensor that controls the gauge on the dash. The one on the back of the engine is the ECU sensor and the one on the bottom rad hose is the rad fan switch.
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  13. S3 GAZ
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    S3 GAZ Member

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    No as far as I'm aware the sensor is a dual gauge and ecu sensor
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  14. Jama665
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    Jama665 Member

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    well Thats what the audi bloke told me, as i did think the same,so I asked what the sensor on the thermostat was for and he said that its for the gauge. but I've known Audi to be wrong before.
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  15. bowen
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    bowen Member

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    ok, now the coolant light comes on. There is plenty of coolant in the bottle?
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  16. Tooks
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    Tooks Active Member

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    Is the plug underneath the coolant reservoir plugged in?

    Or, when refilling the reservoir, did any water/coolant spill down the side and run down into the level sensor plug? Water in there may cause a short that triggers the low coolant warning.
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  17. bowen
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    bowen Member

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    pic request?

    Where is the temp sensor and thermostat?

    going to replace both.
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  18. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    bowen likes this.
  19. bowen
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    bowen Member

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  20. bowen
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    bowen Member

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    ok after taking the a4 to a local mechanic, he said that the water pump had gone. so i bit the bullet and left it with him to fix.

    I got a phone call an hour later to say, the timing belt was so slack that, he was suprised it hadnt fallen off. As it was so slack it was missing on the waterpump, giving the impression it was broke.

    so he timed/tightened it all back up and.....wow....what a different car. pulls so much better, its like a mini remap!

    however, he replaced the (green) temp sender and since then it hasnt gone above 50c? and (and its a big and..) my fans are on permanantly?

    help!?
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  21. bowen
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    bowen Member

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    Help!
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  22. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    I assume you've taken it back to him to sort out?
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  23. bowen
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    bowen Member

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    No, he's ok for some jobs mate but he isnt the kind to give me a recipet. Im working away next week, i may just leave the car at a local audi specialist.
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  24. bowen
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    bowen Member

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    sorted. the waterpump was obliterated, nothing left of the impeller. also the head wasnt torxed down.

    also, dont know if i mentioned the jump in revs as i changed gear? well it was the clutch switch, easy peasy.

    happy, but now i have a roof problem!
    #24

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