Coolant Sensor Head Scratcher....

[mike.c1979]

Hi

I bought my A3 1.8T Sport witht he temperature gauge not working.

I assumed it was the sensor so I swapped it out for the green updated version.

Anyway, my gauge still isnt working.

I have also noticed that the fans kick in a couple of seconds after the car ha started even if it is cold. It is like they are always on when the car is started.

Its still a bit lumpy on idle too.

Has anyone else had this? Any ideas???

Thanks

 

[Vex182]

Best guess would be that the thermostat is stuck open, very common on these 8Ls.

 

[mike.c1979]

Any idea on the fix mate?

Cheers for the reply by the way.

 

[mike.c1979]

My blowers heat up nicely. Im confused haha

 

[mattyboy199]

its the thermostat, mine is doing the same if you sit in traffic your find the car warms up & hits 90 once moving it will reduce in tempreture. Audi world forums has a how to guide on replacement quite easy to do.

 

[mike.c1979]

Thats great thanks, just ordered one at £7 all in.

Do your fans kick in straight away?

And my temp gauge stays at 60 all the time. The only tine I saw it change was when I flushed the coolant system and put new coolant in.

 

[Sam_]

Yeah mine done the same when I got it. New thermostat (decent 1/4" ratchet is well handy) and it was sorted. Make sure you don't get some mickey mouse chinese thermostat...

 

[Tooks]

Thats great thanks, just ordered one at £7 all in.

Do your fans kick in straight away?

And my temp gauge stays at 60 all the time. The only tine I saw it change was when I flushed the coolant system and put new coolant in.

Don't forget that the smaller of the two radiator fans should be running when your AC is on.

Does it stop when you turn the AC off, by that I mean pressing the ECON button?

I wouldn't go with the cheapest thermostat you can find, a genuine one isn't much more money, and you'll save the money on coolant alone if you have to swap out a cheap one too soon.

Don't forget to buy the correct coolant too, the G12 stuff.

 

[mike.c1979]

I think its sorted. I turned the aircon unit off completely and went for a drive. The temp gauge went up to 90 degrees as the fans didnt come on. I turned the unit on again and the fans kicked in, and the temp dropped to 60 degrees.

 

[Tooks]

Its good it seems to be ok now, but it should still warm up to 90 even with the fans on. Only the aircon fan, the smaller of the two, should be on when the AC is on, I'm fairly sure.

I think you've either got a dodgy thermostat, or the 'fans on constantly' problem, or both!

 

[mike.c1979]

I will replace the thermostat tomorrow, see if that works.

Any idea on the cure for the "fans always on" problem?

I unplugged the fan switch but the fans still come on when the aircon etc is on - tad confusing.

 

[Tooks]

There's a bit more info on a possible cause here, but have a google and there should be plenty of others.

http://www.audi-sport.net/vb/a3-s3-forum-8l-chassis/173366-fan-problem-plzzz-help.html

 

[mike.c1979]

So really it must be the thermostat or the fan controller??? Ive obviously replaced the sensor and the issue now is that with the aircon unit on, both fans come on and bont allow the temp gauge to increase

 

[Tooks]

To be honest, you could have two separate problems, just impacting on each other.

I would change the thermostat as you've got one on the way, and see where you are after that.