Many Flex-a-lite electric fans can be reversed, so they can be used as either a pusher fan (an auxiliary fan mounted to the front of the radiator) or a puller fan (primary cooling fan, mounted behind the radiator). The process of reversing them is easy and straight-forward.
Lift the blade off the shaft (you may have to wiggle it side-to-side while lifting), turn the blade over and insert it back onto the shaft. Re-install the E-clip.
There are two steps to convert a puller electric fan to a pusher, or visa versa. The first step is to turn the fan blade over. In most reversible Flex-a-lite electric fans, the fan blade is retained on the motor shaft with an E-clip. Use a pick or flat-blade screw driver to remove this clip. It is helpful to keep one hand over the clip while trying to remove it to keep the clip from flying across the room when it releases from the shaft.
The second part of the reversal is to connect the fan wires in the opposite direction…what was the positive lead is now the negative, and the old negative lead is now the positive.
Once you are done and have the fan installed on the radiator, you can verify that the fan is pushing or pulling as desired by following the steps in this video: https://www.youtube.com/watch?v=okBY5r7S-Qw