Why is my Audi engine making a loud knocking sound?

I've noticed a loud knocking sound coming from my Audi's engine. It only happens when the engine is cold and goes away after a few minutes. What could be causing this issue and how do I fix it?

The most common cause of a loud knocking sound in an Audi engine is a faulty hydraulic lifter. They can become worn or clogged and start to make noise, especially when the engine is cold. It's important to get this fixed soon as it can cause further damage.

Another possibility is that the oil in your Audi's engine is too thin or low. This can cause the lifters to make noise as they are not properly lubricated. Check your oil levels and consider switching to a thicker oil if necessary.

Another potential culprit could be a loose or broken engine mount. When the engine moves around, it can cause knocking sounds. Have a mechanic inspect your engine mounts and replace them if necessary.