iNfiNkC

my wife was driving the q yesterday, she said the ac wouldn't come on, and hot air was blowing out. No engine lights came on. she noticed the water gauge about 3/4 to full hot. I checked the car when she got home, the engine felt very cold. The radiator hoses were both warm and full.

Any suggestions? a new thermostat was put in about 10k ago.

im thinking water pump? is there a mechanical pump or just the electric one?

smith2010Q7

Can you scan for codes anyway. Sometimes a code will be there and it is not strong enough to turn on the CEL light.
There is way to many areas that can cause your problem, hopefully we can pin point it to one area.

Second ? is did the shop bleed the system after replacement of your thermostat? The Q7 coolant system if not bleed correctly will cause blockage.

Thanks

Dtomasi

Could be a air pocket on the coolant temp sensor if the system wasn't purged right.

iNfiNkC

update to this

It was another bad thermostat. First one failed in the open position and the car wouldnt get warm.

This one failed in the closed position.

There was one code via vag com for a short on the thermostat. I measured it and it was bad.

Have another new one in the car now and its happy to be back on the road.