Dexcool is a poor coolant , it degrades easy after just a few years and leaves a brown muddy looking mess in your cooling system.
It is Fine if you change it every few years , even though it says lifetime.
Lifetime ...really is a farce.
Running it wont hurt, I dont like it because so many people NEVER CHANGE THERE COOLANT and that is where the problem occurs.
It degrades like I described...after a few years, turns to mud.
Glycol .. does not...BUT remember it TOO HAS A LIMITED LIFE.
A coolant may transfer heat well , even after several years of use. Big problem is that the anti corrosive propertys which are more important , are pretty much depleted after about 3 years. So changing the coolant and flushing is really a great Idea. Or drain and refill once a season.
As far as changing it out... Meh.... Wait for a year or two, then do a complete flush and use Glycol,and try to get a low silicate formula if you can spot one.
Fact is stranger than Fiction