[BotaBigot]

Technically a neat idea, and that fan looks like it might work. My concern is exhaust and other engine compartment fumes. You would have to run the exhaust far enough back to not be drawn in with the cooling air. And, any gasket/seal leaks on a hot engine could create fumes. I'm guessing you want to avoid the hassle of a heater core. How about some form of electric heat?