Why is the engine in my Audi making knocking noises?

I recently noticed that when I start my Audi, the engine is making some loud knocking noises. This is particularly concerning because I have always taken good care of my car. Any ideas on what could be causing this and how I can fix it?

It is likely that the knocking noise is coming from the engine's valves. This could be caused by a buildup of dirt or debris, which can affect the valve's movement and create noise. I suggest bringing your car to a mechanic for a thorough cleaning and inspection of the valves. This should resolve the issue.