# Coolant Temp Sensor question



## jimmyflo (Apr 15, 2009)

Does it affect the performance if it's not working properly?


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## keith (Feb 15, 2009)

i think it can effect petrol and some other things i changed mine because light
came on the dash not dear not a big job.


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## garyttt (May 14, 2009)

keith said:


> i think it can effect petrol and some other things i changed mine because light
> came on the dash not dear not a big job.


 hi there just read what u quoted bout the coolant temp sens do u know where exact it is located as was guna hav a go at changing mine the weekend as my lights on


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## keith (Feb 15, 2009)

mine is in the front 3.2 not sure were yours is some one will proberly be on and 
tell you were it is dont drop clip like i did buy new one i tied cotten around it
second time to make sure. got from audi about £20.


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## Nick 225TT (Jun 6, 2008)

Very easy job

you dont even have to drain the system to do it

did mine myself took around 10 mins

I think there is a good guide on waks website

here ........

http://www.wak-tt.com/tempsensor/tempsensor.htm

hope this helps 

And correct me if I'm wrong but yes it will waste fuel
if its faulty as the ecu will run rich 
if temp sensor tells it the engines cold when its not I think :wink:


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## jimmyflo (Apr 15, 2009)

thats what i thought nick, I noticed on my passat almost straightaway as I had a boost gauge and it was never hitting max boost as the 1.8ts are restricted when they are cold. But I have no boost gauge in the tt and although I have noticed a slight dip in performance its difficult to tell with it being so quick anyway


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## paszko (Dec 2, 2009)

i have a 3.2cc TT and have recently replaced the coolent sensor (had black now have a green one).

a warning light now comes on which means that the coolent is either too warm/cold. i have been told that their is another coolent sensor which is attached to the coolent bottle.

does anyone know if this is correct and what the part number is as the dealers need me to take it off before they can tell me which one it is.


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## keith (Feb 15, 2009)

think water res might have a coolant leval sensor dont think it has temp sensor.
tell dealer it is a engine coolant temperature sensor that is what i told them and
no problem and it should be green.if you change yours tie a piece of cotton around
the clip i dropped mine and could not find it so had to buy new clip renew anyway.
in book it has (g62)that number might help or confuse them.


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## fishface (Nov 25, 2006)

jimmyflo said:


> Does it affect the performance if it's not working properly?


It can cause all sorts of running and starting problems by sending false information to the ECU, it is quite easy to change though here is another guide http://www.audiworld.com/tech/eng66.shtml


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## tt z (May 7, 2012)

an old tread this is but I'll add my finding anyway.
My coolant sensor was intermittent for some times. Couple of weeks ago I lost cabin heating on air con. It was blowing only cold air but not the warm one. Checked the reading for a fault code but none there apart the same coolant sensor intermittence. Today I changed the sensor, all in all 10 minutes work, and the cabin heating is back.
Seams that coolant temperature sensor affects somehow the work of air con and heating.

8)


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## Sigasiga (Mar 16, 2014)

Just picked up new green sensor, but where is it in a 53 plate 180 got pic of engine,if anyone can point me in right direction it would be appreciated.


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## Sammyjc (Feb 24, 2014)

tt z said:


> an old tread this is but I'll add my finding anyway.
> My coolant sensor was intermittent for some times. Couple of weeks ago I lost cabin heating on air con. It was blowing only cold air but not the warm one. Checked the reading for a fault code but none there apart the same coolant sensor intermittence. Today I changed the sensor, all in all 10 minutes work, and the cabin heating is back.
> Seams that coolant temperature sensor affects somehow the work of air con and heating.
> 
> 8)


Useful to know. I thought if the heating isn't working well the this could mean the thermostat needs replacing but if changing the sensor improves the heating then this may mean it's just the temp sensor I am having problems with. 49c on air con display shows coolant temp all over the place, rising to 121c from 90c within a few seconds then back to 90 again. My liquid gauge gives a different coolant temp of high 70s to low 80's. Car doesn't seem to overheat at all. The dash gauge follows the 49c readout. Got a new temp sensor so will stick this in this weekend and see what happens...


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## Hoggy (May 8, 2002)

Hi Sam, Temp sensor feeds Code 49c, ECU & dash gauge, so will not affect the amount of heat from heater. 
Change your temp sensor 1st as your erractic readings, appear to be temp sensor prob. Use OEM sensor.
If Code 49c still shows low but more consistant coolant temps, replace thermostat.
Hoggy.


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## Sammyjc (Feb 24, 2014)

Thanks Hoggy.

Is what tt z observed then not explained by his changing the temp sensor ie he got cabin heating back after changing the sensor?


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## Hoggy (May 8, 2002)

Sammyjc said:


> Thanks Hoggy.
> 
> Is what tt z observed then not explained by his changing the temp sensor ie he got cabin heating back after changing the sensor?


Hi Sam, No relationship, must have just been a coincidence.
Hoggy.


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## tt z (May 7, 2012)

Sigasiga said:


> Just picked up new green sensor, but where is it in a 53 plate 180 got pic of engine,if anyone can point me in right direction it would be appreciated.


Hi, If you are still in doubt for the sensor position, on my 03 225 the sensor is attached to the pipe running in the direction of the car ( orthogonal to the engine), and close to the upper left corner of the battery. Bit lower then the battery corner.
Suggestion: when you are taking in and out sensor do it with the el. harness attached, it is easier to handle. There should be plenty of cable length. Good luck.


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