I've got an '02 A4 1.8t with a tiptronic and nearly 92k on the odo, owned since new. No mods. In the past week I've begun to hear a dull humming sound from the front of the car when accelerating at rpm's above 2200 rpm. It doesn't always happen, sometimes it's faint and other times it's a drone. But when it does happen, it's always at the same even pitch (it's not too high or too low), and only when the car's been running at normal temps (not overheating) and accelerating (not when idling) from either a stop or just speeding up on the highway. There's no apparent loss of power. Any ideas? Related to the turbo? Timing belt was replaced at 85k. Thanks...

I don't think it's the fan, but it may be... I realize now that it's only started happening now that it's hot climate. I ran it tonight in cooler rainy weather and it was fine...

Did you ever find out what was wrong with you car? My car is making a humming noise when I accelerate from a complete stop up to an approximately 20 mph speed and then it disappears. It also hums while making a slow speed turn. I'm thinking it may be low on transmission or steering wheel fluid, but I have not confirmed. But, hopefully it is not the driveshaft or something else more expensive.

Any suggestion on what may be wrong with the vehicle?