When my thermostat failed open and it was below freezing out I stuffed a piece of foam into the clutch fan to keep of from moving in addition to cardboard in the grill so the engine coukd get to closed loop and I could get cabin heat.

I think the clutch fan does very little to cool the engine over about 80 kph.

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)