Why does my Audi's engine make a knocking sound on cold mornings?

I have noticed that on cold mornings my Audi's engine makes a loud knocking sound for a few seconds when I start it up. What could be causing this and is it something I should be worried about?

This sound is likely due to a lack of lubrication on your engine's pistons and cylinders. As the temperatures drop, the oil in your engine can become thicker and take longer to circulate, causing the knock. This is a common issue in colder climates and should not be a cause for concern. To help prevent this in the future, try using a thinner oil or using a block heater to warm up your engine before starting it on cold mornings.