S3 8p (57) Dash Temp Gauge

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Wrexad

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How does everyone temp gauge seem to be in their S3 8p? My mate has not long had his but since picking it up the temp gauge doesn't ever sit at 90, It does reach 90 but once being driven will drop back to around 85 on the dash pod. Does anyone else get this? We have replaced the ECT sensor in the side of the engine block (on the right side) which has made it a little better but it still moves around.

I know theres movement in the water temp while driving but i have never seen a cars temp gauge move from 90 once hot as i thought the gauge stayed at 90 even if it drops to 82ish.

How many temp sensors does this engine have? Is there a 2nd we need to replace somewhere?
 
Engine thermostat. Mine was the same when I got it, so had it changed and now sits bang on 90 all the time :)
 
audi upgrades
Aye, Thermostat.

Mine used to always sit around 80-85 and never go to 90. Till I replaced it.
 
Thanks for the help, But is there any way of testing it or is there not much else which would cause the temp to drop like that?
 
Its a very common fault and not too expensive to fix so would be worth doing anyway imo.

No other way im aware of anyway....

Maybe someone else can assist.
 
Wrexad said:
Thanks for the help, But is there any way of testing it or is there not much else which would cause the temp to drop like that?
Click to expand...
Nope just replace it. Now the colder weather is here, this will be a common post on here.
 
just noticed this thread before I created a new one with the exact same problem. fluctuation from 80/90 new sensor but still doing the same...
 
Mines doing the same.. won't cause damage to leave it for a while will it?
 
No won't cause damage... but that doesn't mean leave it for a 1000's of miles. As soon as you get a chance, replace it.

And I'd cut back on the heavy right foot driving..... just a wee bit.
 
Noticed my temp gauge had fallen to 50 (not moving) on the way home tonight where before it was dead on 90 all the time, although last night i did notice it drop a little to 85. I'm just sitting waiting with the battery disconnected to check if it comes back on after ecu reset. One thing after another with this motor, It's back in the garage again tomorrow so if it is the thermostat will get them to look at that too.
 
So the reset did get the gauge working again, but not perfectly on 90 as it was before. Not had chance to see if it is still working ok today on the 200 yard drive to drop it at the garage. I'm thinking of getting the parts and doing this myself after reading how to do it, just need to ask myself if i still have the patients I used to for working on cars...

There are definitely no harmful effects of the gauge showing 50 if it does it again?
 
Yes it can over fuel, the car is designed to be at 90 deg its optimum temperature youll see the mpg increase when working 100%
 
Ok thanks, won't delay then :)
 
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Now I'm confused (more so) looking for a thermostat (coolant regulator) for my car 2004 3.2L and they all say 80C, it deffinately has been running at 90C am I looking at the wrong part, anyone confirm the one I need, Ta
 
Hi again, So the gauge did stop working again next day when it was cold morning, sometimes it pops back into life though when I'm driving.

Can anyone explain whats happening as I like to try and understand what the causes are, The radiator fan is always blasting away when I come to stand still so presumably when driving along too, what is the car "thinking" is happening.

Ta :)
 
Have you replaced the thermostat (not the sensor one on the engine block)?

If the thermostat is stuck open then it could be the the coolant doesn't get to 90 as the water is flowing round the system. On warm up the thermostat should be closed so the water can heat up quicker. Once it gets to the required temp then the thermostat should open and close to regulate the temp and keep the coolant at 90 - which is why when its working properly it should stick at 90.

I'm not sure how the radiator fans work or where they pick the temperature up from. I presume its sensor on the radiator and they kick in when the water in the rad gets to a certain temp. Not sure if the S3 has two speeds for each fan as some Audi cars do.
 
If the gauge is erratic it might be the coolant temperature sensor (CTS)
If the gauge gets to 90 when stopped and falls when moving, or no load on the engine ie coasting it's the stat.
 
pluves1 said:
Have you replaced the thermostat (not the sensor one on the engine block)?

If the thermostat is stuck open then it could be the the coolant doesn't get to 90 as the water is flowing round the system. On warm up the thermostat should be closed so the water can heat up quicker. Once it gets to the required temp then the thermostat should open and close to regulate the temp and keep the coolant at 90 - which is why when its working properly it should stick at 90.

I'm not sure how the radiator fans work or where they pick the temperature up from. I presume its sensor on the radiator and they kick in when the water in the rad gets to a certain temp. Not sure if the S3 has two speeds for each fan as some Audi cars do.
Click to expand...

Would this mean the coolant/engine never warms up? if so wonder why the fan is on
EDIT: Oh and no, I didn't get the work done in the end, wish I had now though!!

LEE69 said:
If the gauge is erratic it might be the coolant temperature sensor (CTS)
If the gauge gets to 90 when stopped and falls when moving, or no load on the engine ie coasting it's the stat.
Click to expand...

Either the temp gauge is down at 50 and doesn't move or it goes back to just under 90 and works until next morning (not seen it go from working to not working while driving along)

Definitely doesn't fluctuate once the gauge is working..
 
Update: was the CTS in my case
 
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