Why does the Audi A3's engine make a whistling noise?

I recently noticed that my Audi A3's engine makes a high-pitched whistling noise while driving. It seems to occur when I accelerate or reach high speeds. What could be causing this and is it something I should be concerned about?

This whistling noise could be caused by a loose or damaged serpentine belt. It is recommended to have a mechanic inspect and potentially replace the belt to prevent any further issues or damage to the engine.

Another possible cause could be a faulty vacuum leak. This can affect the performance of your engine and should be addressed by a professional as soon as possible.

I have also experienced this issue with my Audi A3 and found that the noise stopped once I replaced the air filter. It may be worth checking and replacing yours if it is dirty or clogged.