Curious temperature problem

[sportquattro]

My 1999 APY S3 normally is up to temp (90 deg) within about 2 miles of leaving home, however, last few days its taken a good 20 miles. Once it eventually get there its seems fine, sits at a steady 90 degrees as normal. My first thought was Temp Sender of Thermostat, but given that one up to temp it behaves normally, I'm having second thoughts. One thing I have noticed is the fans seem to run from first start, I would have only expected them to run once up to temp and only if getting hot hot.

Any thoughts most welcome, have not had chance to run VAG-COM yet.

Nige

 

[sirbobalot]

Hi mate I would of went for the temp sensor first my a3 had the same sort of problem from cold would come up a little then would be sitting fine at 90 but then I could jump out the car for 2 mins start her up again and would be at 0 then other times I could jump in the car in the morning start it up and fan would run but engine is stone cold. I changed the sensor and flushed the system through at the same time bit of sluge came out but haven't had a problem since. Hope it helps.

Robert.

 

[hades-]

scan first

cts is easy to change and not a lot of ££££

then stat is above fails

 

[rhinopower]

I had to do stat and cts on mine, thats life!

 

[pj123]

Fans should both run from cold if the air conditioning is switched on. If the AC is off then the fans should run when the temperature reaches high 90's. You can check engine running temperature using the climate control trick. Press Recirc and up together then use+ to go to 49 and press recirc again. My fans cut in at low speed when 100 is reached.

Fan cut in/out is controlled by a switch in the radiator. Coolant temperature sensor is used by the ECU, dash display and displayed on the climate control. if you switch off the ac and fans remain on with engine cold then i would look at the switch in the radiator or the control unit.

If its taking a long time to warm up (greater than 10 minutes) then i would replace the thermostat first with a genuine part. I have tried a cheap thermostat before and ended up doing the job twice.

 

[sportquattro]

Have ordered new genuine CTS and thermostat, will report back once fitted at weekend hopefully