SLOW Heat

[rhughes@domain.elided]

My heater works, but it doesn't start blowing hot until I'm almost to work
(about 25 minutes).  In addition, when I get on the freeway, the cold fast
air cools the engine down so much that the heater starts blowing cool
again.  I'm looking for a way to solve both problems.

I've heard that you can stick a piece of cardboard with a hole in it
between the radiator and fan, restricting airflow to the fan, heating up
the engine.  Is this a bad idea?  How big should the hole be?

Other suggestions?  Warnings?

Rob