"This double vanos can be found on 6-cyl engines M52TU, M54, and M56, found in several model cars, E39, E46, etc, years 99-03. The malfunction symptoms are almost all subtle and mostly go unnoticed. They include lower gas mileage, lower performance, degraded emissions control, and possibly others. "

Some stuff here: http://bimmer.roadfly.com/bmw/forums/e39/7494631-1.html

Damn.. should I buy a new vanos or try to do some repair first. The problem is that there is no way to check if its the VANOS problem for sure on M54 engine. It wouldnt make any sound anyway..