I'ts been perfectly stated above. You could cool it with the blower motor from a furnace and it would still overheat in the summer. The air temp is already going to be hot so you will just be blowing already hot air on hot heatsink.
For a cpu cooler to cool, it must be able to disapate the heat. To disapate the heat the temp of the air blowing on the heatsink must be cooler than what the heatsink is drawing from the CPU. The system will try and reach equilibrium by transfering the heat of the cpu to the air. If the air is hotter, it works the other way, the air will heat up the heatsink.