My '08 Chevy 2500HD 6.0L is now past 5 years old, has 34K miles on it and I believe that it is time to change the coolant. In prepping to do the job I discovered that the radiator in these vehicles do not have a drain on them and this makes the job a bit harder and more involved, and this has caused me to do a gut check and rethink the issue. I was planning to flush out all of the Dexcool and covert it over to standard ethylene glycol coolant because of I what I had heard about Dexcool in the past. Because of the amount of work, and mess, I'm starting to wonder if I should stick with the Dexcool? What's the story with the stuff, why are they using it especially considering that Prestone is supposedly good for 5 years/100,000 miles? Any adverse effects of using the green stuff in a vehicle that's designed for Dexcool? Let me know your thoughts on this. Thanks, Adam.