Thermostat on an S3?

Wallm0nkey

Registered User
Been having issues with the temp gauge sometimes it works upto temp but generally stays at the bottom I'd assumed it was cts. Had the same problem on a bora which it solved so I changed it and it's still the same. All the thermostat issues I'd read about seemed to be false readings? Heater works fine I think I'll swap it anyway just curious as to whether anyone else had the same problem?
I recently got vagcom can I use it to gain any more info before I carry on?
 

seafar99

Registered User
I had the same problem with mine. Changed the thermostat, problem solved. As the temp gauge doesn't start to register till water temp reaches 60* , it can take a while ,especially in freezing outside temperatures.
 

S3quatt

Flat Oot like a ducks Foot
VCDS Map User
One way you will know if its the stat sticking open is fuel consumption will go through the roof.
Happened on mine & it sat around the 60 mark.
 

Wallm0nkey

Registered User
To be honest I have only been driving the car on the odd occasion stuck in a van most my life and my girlfriends in the S3 but not sure if she would notice the fuel or not. With any luck I'll get it sorted this weekend!
 

ManuGD

Registered User
My thermostat also failed last year.
During the summer I could barely notice it, but in the winter the temp never went over 60ºC.

I tried to replace it without removing the alternator, but there was a bolt that was a pita to remove.
With the alternator out is way easier but it takes more time because you need to remove the poly-V belt.

Good luck with it!
 

SteveBAM

Black '03 S3
I bought a new thermostat today,now that winter has come and the temperature has dropped the engine temp struggles to go above 60. Had a bit of a look on how to change it and its seems that there is a bolt behind the alternator that is F@k!.g impossible to get out without removing the alternator.Any tips on how that lower bolt can come out without taking out the alternator?thanks
 

SteveBAM

Black '03 S3
ok thanks for your help, i just finished changing the thermostat without taking the alternator out.There is enough room to get that bottom bolt out,all you need is patients and a little bit of tool working skills. ;)
 

Wallm0nkey

Registered User
Finally got around to doing it today and temp was sitting at 90 nicely. That bottom bolt is a pig but managed to leave alternator in place. I drained the coolant and made a shield to keep the alternator dry too which seemed to work. Hopefully I won't need to mess with it again!
Has any one else had a faulty thermostat throw an engine light up? Happened the other day scanned with vagcom and it had a code and said cts or thermostat didn't realise it would cause a light.
 

CazzaVR

Registered User
I had light and same error message with mine. All ok now with new stat and sensor :)
 

Wallm0nkey

Registered User
Yeah mine is working as normal again now! Just hadn't seen mentioned anywhere about a fault code everyone just reported strange temp readings.
 

Wallm0nkey

Registered User
We have a sensor also only takes a about 5 mins to change it! Remove the main engine cover and it's on the down on the right new parts green not sure on the older one?
 
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