Good God, there is so much WRONG or at least outdated information in this thread.
For the original poster: I have used "ordinary' green, I've used Dexcool, I've used non-Dexcool extended-life; and I've used "less-toxic" Propylene Glycol (Sierra brand) antifreeze.
ALL of them have worked JUST FINE. At this point, I lean toward non-Dexcool extended-life; largely because I've gotten lazy about coolant flushes, and the non-Dexcool costs less than Dexcool.
If I owned a vehicle that specified a particular coolant, I'd consider using the special stuff. I'd at least research the benefits of the specified coolant. Deathcool/DexKill USED to have problems with gaskets. The gaskets have been improved, the Dexcool formula has been changed...I think this is a "done" issue.
I ALWAYS tend to mix them "strong", more anti-freeze than water--up to 80% antifreeze; because it used to get really cold here. Thank God for global warming; I'm now mixing about 60% antifreeze, 40% water. If your engine overheats because you have "strong" coolant, your cooling system is under-sized or there's some other problem. I'm good to 100 degrees + with my "strong" coolant. I don't know how much hotter the outside temp could get, 'cause I've never overheated except when the head gasket popped on my Lumina. (it was February, at night, about -10F)
"Regular" Green anti freeze is supposedly good for two years before it needs to be flushed and re-filled. Have fun. I test my coolant for acid and freeze protection. My experience is that the green is good for 4+ years without problem.
The "Extended-life" coolants are supposedly good for 5 years. Have fun. I test my coolant. I've got no problem going seven to ten years with it.
I think the "two" and "five" year coolant flushes are exactly the same as "3000 mile" oil changes--a tremendous waste of time, money, effort, and enthusiasm PROVIDED YOU CHECK and TEST THE COOLANT NOW AND THEN. Although I've not done it, there are sacrificial anodes that will ward off cooling system corrosion, they're probably a smart move--but I never think of them until I'm answering a question. Gonna have to check Amazon to see what's available. I think Magnesium works better than Zinc, but either is better than nothing.
If you're using "regular green", you can buy test strips that show the level of acid and the freeze protection. It's harder to test extended-life coolant. It's worth checking the coolant for voltage using a multi-meter; electrolysis is evil whether it's a poorly-grounded engine component or depleted additives in the coolant.
https://www.amazon.com/WIX-Filters-...rds=Coolant+test+strips&qid=1589234951&sr=8-3
https://www.amazon.com/Cool-Trak-31...rds=Coolant+test+strips&qid=1589234951&sr=8-6
I buy "pure" or "Full-strength" coolant, and gallon jugs of distilled water. Distilled water is under a dollar a gallon. One gallon of anti freeze is maybe fifteen dollars, sixteen with the water. Makes two gallons of coolant. Two gallons of "50/50" or "Premixed" coolant is about $25.
Gotta be nuts to buy premixed.
Engines had aluminum components in the early '60s, and even before that. Advertising that coolant is "aluminum safe" is crazy, because it all is. Nothing special about "aluminum safe" glycol-based antifreeze, and folks haven't used methanol as anti-freeze since WW II.