I had several oil leaks on my 2001 325i. I replaced the Valve cover gasket, oil pan gasket and finally the gasket from the oil filter housing to the engine block. After finishing, I immediately noticed that my oil filter started leaking. I replaced all the o-ring seals on the filter and it stopped leaking. But then I got another leak from what appeared to the oil filter housing gasket again, and a significant leak, worse than before. I was very surprise to see so much oil leaking and immediately thought that I somehow installed the gasket incorrectly so I took everything apart to check the gasket. The gasket look fine, so I put everything back together very carefully, but I got the same leak. I double checked the oil line from the housing to the vanos system, but it did not seem to be leaking especially for the amount of oil being leaked. It was almost as if there was no gasket at all. A friend thought that maybe my Vanos was malfunctioning and not allowing oil to to flow into it causing an increase in oil pressure and forcing the leak. I don't know about this, so I'm here to see if there can be any other reason for the leak. I really hoping to find the solution for this, I'm tired of all the oil leaking. So any suggestions will be great.