Why is the engine making a knocking noise in my Audi A4?

I recently noticed that my Audi A4 engine is making a knocking noise. It started after I had the oil changed. What could be causing this?

This could be caused by a few different things. Firstly, I would recommend checking the oil level and making sure it is at the correct level. If it’s too low, that could be causing the knocking noise. Another common cause could be a worn timing chain or tensioner. If the engine oil was changed recently, the timing chain may have been disturbed or not properly aligned during the oil change, causing the noise. I would suggest taking your car to a mechanic to have it checked out and repaired if needed.