Jon_Leech

Hello,

I'm writing on behalf of a friend of mine who's having some issues with her 2004 A4 1.8T.

Driving around town, the car is fine, no lights, engine temp is normal, AC is cold.

She went on a long journey (2 hours) and on the way there, the coolant light turned on, and the AC started blowing out warm air. The temperature gauge went up slightly, probably 5/8ths.

The next morning she checked the coolant, which was at about half way between min and max, and topped it up.

Driving home, the AC was initially fine with no warning lights, but as the journey progressed, coolant light on, the temperature gauge varied from half way to 3/4, back and forth. The AC blew hot, then cold, back and forth.

Any ideas what this could be?

Her local shop was going to change the thermostat (for $550!!), but they don't know Audi's and so she's currently booking it into an Audi dealer in LA (2 hour drive). I'm aware of how much Audi dealers charge!!

Could it be as simple as the AC fan?

Any help would be greatly appreciated....

Thanks,
Jon

lyleswk

I will say two things: generally, the thermostat fails open and the car runs too cool. FYI, the Audi does not have a simple mechnical spring thermostat; it is electrically controlled by the ECU. If anyone has had a different experience, please pipe up.

As far as fan, a malfunctioning fan would cause overheat at sitting in traffic, not at 70 mph there is plenty of air going over the condensor and radiator. The only situation here that makes any sense since you are overheating and losing AC at about the same time is that the fan can't spin freely and is actually blocking air from flowing freely over the condensor and radiator. Might spin the fans and see if they spin freely.

Other than that, never heard of both being an issue at the same time. Overheating at speed alone would indicate a bad water pump. AC going out after a while would indicate it needs to be serviced with freon. The 2 simultaneously? Odd, unless the fans won't turn at all.

Jon_Leech

Thanks for the info and suggestion, I've asked her to check the fans turn... (with the keys out so she doesn't lose a finger!)

Will post back...
Regards,
Jon

Win2000

I have similar symptoms. My fans have both failed and are currently disconnected, while i wait for my replacements to arrive.

My symptoms;

While stopped at a stoplight, the AC starts blowing warm air.

When i drive around the AC starts blowing cold.

Car only overheats on warm days in stop and go traffic.

You can check the fans as follows. Start the car, turn on the AC. Now look under the hood, both fans should be spinning. If not, you have a problem with the fans or your fan controller.

lyleswk

Note his is the opposite problem, meaning he gets warm at speed and the AC stops working at speed.