Don't know much about Audi's so bear with me.

Driving in the city today in my 2003 A6 3.0 with the air conditioning on - was working fine then all of a sudden the air got warm and the car overheated. I got to a parking space and popped the hood - coolant on the engine smoke pouring out. I couldn't tell where the coolant was coming from. Also seems like the fans in the engine are not working when i turn the AC on. The AC will not get cold now.

I just had my timing belt/water pump changed last week. Spoke to mechanic who said didn't think it was the issue and could be a fuse under the steering wheel that controls the aux fans in the engine. Checked the 50 and 60 amp fuses -they looked fine. Anyway how would this explain the problem with the coolant leaking?

after i let it cool down i drove a bit to see how it would react. car temp was fine - i parked it and came back 15 mins later to find a pool of coolant on the ground near the right front passenger side of the car. If the fans aren't working, could this cause coolant to escape? Does this sound like a bad water pump or bad install from the mechanic? Or something else? Two separate problems? Help!

 

lower radiator hose?

thermostat/thermostat housing?

could be a bad timing belt and accessory install. could also be a LOT of other things.

is your mechanic an audi tech/specialist?

 

Since the water pump was changed so recently, the mechanic probably caused this. If he was not familiar with the car, he probably did not know about the two bleed locations, one hidden under a clamp in the body intake plenum, for replacing the coolant and the car got an airlock in the cooling system. This can trash an engine, a good reason to only use a specialist for repairs. I have seen many a Mini Cooper destroyed by airlocks.
The overheat may have caused some damage that has resulted in a coolant leak at the pump gasket or seal. I would be back to him to point this out and get a feel for whterh he is really capable of making the car right. You're lucky if this didn't blow a gasket or warp a head.

 

I should also have mentioned that the fans could be disconnected or the harness damaged if the fuses and relays are good, which would cause overheating in traffic. Be sure to find out why they are not working, don't drive the car without the fans working. I still think it happened during the TB change, it's just too coincidental.

 

Fans are run off a temp switch in the radiator. Remove the plug and run a jumper between two terminals with the key on to see if the fans come on. If they do it's a bad switch.

follow the power -- fuse -- relays -- bad blower motors or bad wires.
BTW there is a resistor on the low speed side that sometimes goes bad but that dosen't stop the high speed fans