Why does my Audi A2's engine make a rattling noise on cold starts?

I noticed that every time I start my Audi A2 when the engine is cold, it makes a loud rattling noise for about 10 seconds before disappearing. What could be the cause of this and is it something I should be concerned about?

This rattling noise on cold starts is a common issue with the Audi A2 and is usually caused by a malfunction in the timing chain tensioner. It is recommended to get it checked and replaced by a certified mechanic.