Originally Posted by troidus
Buy 10' of heater hose in both sizes and pipe it through the passenger window to your shiny new heater core. Strap a 12VDC fan to the side opposite the hose fittings and build a baffle out of cardboard to keep the whole thing off the floor so air can pass through. Tape up the gap in the window. That should give you plenty of heat. Do the real fix in the spring.
Got a suggestion to go here and DIY... www.firstgeargarage.com
Seems pretty cool! $35 an hour to use a heated space....
-4 deg F for the ride home!