Why does my Audi A2 engine make a ticking noise at idle?

I recently purchased a used Audi A2 and noticed that the engine makes a ticking noise when idling. The noise goes away when I start driving but returns when the car is stationary. Is this normal or should I be concerned?

The ticking noise is most likely caused by a faulty lifter in the engine. It's common in older Audi A2 models and can be fixed by replacing the lifter. It's best to have a mechanic take a look at it to determine the exact cause.