What should I do if my Audi 80 engine is making a strange knocking noise?

I've recently noticed a strange knocking noise coming from my Audi 80 engine. It seems to be getting louder and more frequent. Is this something I need to be worried about? What could be causing it and what should I do to fix it?

It is important to have your car checked by a mechanic as soon as possible. This knocking noise could be a sign of a serious engine problem, and ignoring it could result in more costly repairs.