It is cast, it is aluminum (alloy). Am I missing something?

It doesn't take any more power to run an aluminum fan than a plastic one, it's pretty much down to aerodynamics and balance. Rotational inertia can affect startup load, but this is pretty much nil.

__________________

Gone to the dark side

- Jeff

This particular alloy is much heavier and less forgiving than conventional aluminum. It has no bend to it, something hits it, it breaks.

__________________
1996 E300 D
1992 300D
1990 Ford E-350 7.3 Diesel AKA "the Deep Fryer"