The 6-cylinder engine uses double-VANOS on Cylinder head; detachment of the VANOS unit requires extra tools and processes. Before doing repair, it is important to know the process, because if camshafts are disassembled, or removed and assembled, or cylinder head is removed and assembled without enough tools, it is possible to damage or break something. Valves may get bent from contact with the piston crown as can the camshafts which may break if improperly stressed during removal or installation. 'VANOS' is an abbreviation for 'VAriable NOckenwellen Steuerung' which is a German name. The process of removal and installation of cylinder heads is somewhat different as the intake manifold has to be removed before the cylinder head. For such a substantial amount of reconditioning after pulling a cylinder head, there is a remanufactured version obtainable from an original equipment BMW parts supplier.