You have just trod into a can of worms by bringing up that topic. Do a search and you will find that the coolant threads have been debated and exhausted to no end...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car