I can't see exactly how the fan is fit with the radiator but I'm almost certain you could swap its position on the other side ( next to the case fan) with opposite flow direction.
"Dimension: 120 x 80 x 159 mm (4.7 x 3.1 x 6.3 in)"
Take some ruler and measure it 4 cm from the center of CPU slot and heres the answer.