I am becoming a dexcool fan again because of all the aluminum in my cooling systems. I think it provides better protection than the green stuff.

There are test strips that I use on HD trucks and my own cars and SUVs.
There a additive which containns a chemical called DCA or it stands for something. Many different companys sell it, contains nitrates? helps protect metals, all kinds of metal. You add it the the coolant and keep a eye on it with test strips and they will tell you when it's time to change coolant.

Now that I have eddie aluminum heads my green anti freeze was trashed after 1.5 years. I switched to dexcool and it is holding up much better.

there are 3 way test strips also for dexcool also that I use. Pencool is only one of many brands that contain DCA that is used, but you got to keep track with test stripps.