Every Rotary vehicle I've ever owned has had a very marginal heater. Is it something I'm doing wrong or is it just the way it is? How can I improve the heater in my '73 RX2? The fan works on all three speeds. The levers all work as designed but the hot air temperature from the heater in insufficient to defrost the window with myself and three passengers in the vehicle. On a rainy day even with the defroster on, air flow control set to fresh temperature to hot the windows still fog up. Help!!!

 

Pull apart the heater/ac (if it has it) box(es) and clean the cores with compressed air. Seal all the boxes with silicone, and use weatherstriping (the soft foamy stuff with an adhesive back) on the connecting ducts. This is how I fixed my RX-7, so that's the general idea. If the ducts have leaks and such, the airflow will be hampered. If the cores are plugged with leaves/dust/mystery dirt (usually starts to get bad after 10 years of use), that REALLY hampers heating/cooling.
Also, take the blower motor apart and re-lube everything, and make sure the brushes are in good shape.

 

also make sure there is adequite(sp) coolant flow thru it, I think that's what's wrong with mine.