I am the owner of an A3 1.8 t Sport. Its a 1998 model.
My Audi overheats when I am on the motorway, however when I am stationary it seems fine and the fans start working. The temp gauge has gone to at least 100 degress.
Can anyone suggest what might be wrong??

 

Do you mean the cabin temp gets up to 100 degrees or the coolant temp gets up to 100 degrees or the oil temp gets up to 100 degrees?

And what do you mean the Audi overheats? Is it because you get coolant steam from the engine bay or that the gauge reads "hot"?

 

Sorry, the coolant temp get to 100 degress +. The temp warning light comes on. No coolant steam from the engine bay. Also the air con goes warm when the temp rises.

 

Two things to check:
1. Thermostat.
2. Coolant sensor switch.

I'm a little perplexed that 100 degrees is considered hot, though. That sounds normal to me, but I don't know the A3 very well. It certainly is odd that it would register hot while moving and "OK" while stationary. I'm assuming you've checked for leaks and that you've checked to see that your coolant level is correct, right?

It's more than likely the thermostat; check that first.

 

Thanks for the advice. The operating temp has always been 90 degrees until now.

 

Keep us posted on the progress of this humphren. It will be good to have the results posted after you get it all sorted out.

By the way, I'm going to move this thead to the A3 forum later today so that it will be properly archived.