now I have been driving an Audi A8 for 4 weeks, of which I was completely convinced at the beginning... Yesterday, however, I had a 40x40 cm oil stain in my parking lot!

I removed the lining under the engine, but could not find out (because everything was full) where the oil came from.
Now I took the car to a friend (screw) this morning.
He just told me that he suspects that the oil filter is to blame, but that it is protected by a cast iron tub, which makes you very bad... I know how to refill washing water, and what I have to fill up, but it almost stops when it comes to engine etc. I'm going to go.
Maybe. any of you any idea what that could be?!? Please help me so that my dream of A8 doesn't burst again...
) fest. falls der undicht ist, ca 20 euro.