WARNING: This page is about a different car, the 2013 BMW 550i GT, 2012 BMW 550i GT, 2011 BMW 550i GT, and 2010 BMW 550i GT. However, it is still accessible from the selected car via links, so may be relevant.
TIGHTENING TORQUE SPECIFICATIONS - FAN
Type
Thread
Tightening specification
Measure
1AZ Fan clutch on water pump Coupling nut (left-hand threads)