New GM vehicles come with a (claimed) 100k/5yr coolant they call 'Dex-Cool';
I've just discovered Prestone "Extended Life - 5/100" coolant that notes on
the bottle that it is Dex-Cool compatable, & silicate and phosphate free.
(~ $8/gal @ Pep Boys).  It's a vile, bile yellow color, same as the GM
stuff, for what it's worth.  Any comments pro / con from the truely
knowledgeable out there ref using this stuff & maybe going 2-3 years between
coolant changes?

Austin