I see all sorts of problems with cooling systems that use Dex-Cool, mostly corrosion-related. It was originally developed to be more compatible with aluminum than the green stuff, but apparently they didn't test it well enough for long-term use. Older systems, especially the ones with copper radiators, really need to run the plain old green antifreeze. All my vehicles get a 50/50 mix with water- - - - -if that's ever too weak for Tennessee, I'm heading further south in a hurry! Since the coldest recorded temp in our area was -17 degrees F. I think I'm pretty safe!
Jerry