While this thread obviously concerns antifreeze, thought I'd relate an
experience with my friend's Chevy Blazer (sorry).  It stank when he
bought it (used) and finally we took off the sheet metal covering the
ventilation air intake that's just in front of the windshield.  Rat's
nest.  We spent about 30 min. cleaning it all out and problem solved.
We live in New Mexico, and after we were finished my wife reminded us
of hantavirus--we're still here.  Hantavirus:
http://health.yahoo.com/health/Diseases_and_Conditions/Disease_Feed_Data/Hanta_virus/