I'm not extremely familiar with how the heater/climate control system works in the A4, but I've noticed my car is really slow to get heating up on its own. Even after 20 minutes the vents barely push out hot air.

Granted, last night it was -8° when I was driving home and had a high of about +1° during the day, but after 10 minutes I would expect the car to not PUMP out cold air when on the "Auto" selection.

I can set the temp to 75° Auto and within about 2 minutes the vents are blowing, but if I come to a stop or have the engine below 2k RPM the air turns cold. I don't mean cool, I mean like an AC cold. That will continue for 15-20 minutes! The car will only put out the HOT air that I want if I rev the engine. I can put it in neutral and rev it and then I get hot air within about 3 minutes of starting the car.

The car is still under warranty, but I'd like to know the right terms I should use so they listen to me when/if I need to take it in.

Thoughts?

 

you need a new thermostat

 

Is this the only cause? The EXTREME cold wouldn't be to blame at all?

 

not really your car should always get up to temp no matter how cold it is and the heat should always be hot. the thermostat is stuck open causing your car to take a long time to heat up and it is always flowing coolant so it cant stay hot

 

I have just gone through this... the exact symptoms you were describing. Much to my relief it was just a busted vaccuum hose. It was a 20 min, 15 dollar fix at the mechanics. Maybe even something you could replace yourself. As soon as they replaced the hose it worked beautifully again.

 

wait what?? vac hoses have nothing to do with your heating or car warming up

 

Sounds good. Thanks for your help.

 

Had to do with circulating the air through the air system. My mechanic replaced it, and I saw perfect performance out of my heating system, where before you had to be revving it to feel any warmth.