if you reverse the direction the blades will turn the way it needs to. if you have the fan off just hook up the wires. one negative and one pos. see which way it turns and if it is the wrong way switch the posts and it will reverse. think of it more as a ceiling fan. if you switch the little button it reverses direction. even the props on a boat and or plane if they will bolt on backwards it would just have the reverse effect. forward gears would move in reverse and vise versa.
I am in the process of adding an electric fan to mine right now. it came as a fan that goes between rad and engine but is going between grill and rad. it pushes just as much air as it pulled.
