Why Is My Audi A2 Engine Making a Whirring Noise?

I recently noticed a whirring noise coming from my Audi A2's engine. It's not particularly loud, but it's consistent and becomes more noticeable at higher speeds. I'm concerned that it might be a sign of a larger issue. What could be causing this noise and what steps should I take to address it?

The most likely cause of the whirring noise is a worn belt or pulley. I recommend checking your serpentine belt and tensioner first, as they tend to wear out quickly on Audi A2s. If they appear to be fine, it's also worth checking the alternator, water pump, and idler pulleys for any signs of wear or damage.