What causes the loud knocking noise in my Audi A3 engine?

I have noticed a loud knocking noise coming from my Audi A3 engine, especially on cold starts. What could be causing this and how can I fix it?

The loud knocking noise could be a sign of low oil pressure or worn out bearings in the engine. I would recommend checking the oil level and getting the bearings inspected by a mechanic.

Another possible cause could be a faulty lifters or valve train components. It's best to have a professional check and replace any damaged parts to prevent any further damage to the engine.

It's also important to regularly change the oil and filter in your Audi A3 as recommended by the manufacturer. Old or dirty oil can cause engine knocking, so keep up with your scheduled maintenance.