I have a 2001 a6 2.7t.

with out the a/c on i can drive all day...the temp needle is about half way up...

when i drive with the ac for about 15 to 20 minutes the car starts to over heat. it beeps at me and it also shows a dripping faucet on the display.

in those 15 to 20 minutes the ac is blowing cold air. i did make sure the freon was at a good level.

i also noticed that the temperature said 113 when it was actually in the 80's outside...

any clues?

 

Is your electric fan turning on when the A/C is on?

 

My car would overheat with the ac on because the electric fan was not turning on, it turned out to be a bad 40 amp ornage fuse that was preventing the fan from working.