What is causing my Audi 80's high oil consumption?

I've noticed that my Audi 80 is consuming a lot of oil, much more than usual. I've checked for any visible leaks but can't seem to find any. What could be the cause of this issue?

It could be a worn out piston ring or valve seals, causing oil to leak into the combustion chamber and burn off during the combustion process. I suggest getting a compression test done to confirm this issue.

Another possibility could be a clogged PCV valve, which is responsible for regulating the air flow and maintaining pressure in the engine. If it's not functioning properly, it can lead to excessive oil consumption. Check and clean the PCV valve as a first step.

I had a similar issue with my Audi 80 and it turned out to be a faulty oil pressure sensor. It was giving incorrect readings, causing the engine to consume more oil. Have the sensor checked and replaced if necessary.