Why is my 1994 Audi 80's engine making a knocking noise?

I recently purchased a used 1994 Audi 80 and have noticed a knocking noise coming from the engine. It seems to get louder when the car is warmed up. What could be causing this issue and how can I fix it?

The knocking noise could be a sign of damaged engine bearings. This could be caused by running low on oil or not changing your oil frequently enough. I recommend taking your car to a professional mechanic to inspect and potentially replace the bearings.

Another possible cause of the knocking noise could be a loose or worn timing belt. This can cause the engine to be out of sync and create a knocking sound. It's important to have this checked and replaced if necessary as a faulty timing belt can lead to more serious engine damage.

I experienced the same issue with my Audi 80 and it turned out to be a faulty spark plug. When the spark plug is worn out or misfiring, it can create a knocking sound. Have your spark plugs checked and replaced if needed.