Why is my Audi 80 engine making a rattling noise at idle?

I recently noticed a rattling noise coming from the engine of my Audi 80 when I'm at a complete stop. It seems to go away once I start moving again. What could be causing this and how can I fix it?

This could be due to a loose or worn out belt in the engine. It's important to have it checked and replaced if necessary to prevent further damage. I would recommend taking it to a mechanic for a thorough inspection.