From what I have been able to gather from BOBISTHEOILGUY there is a difference. I'll try to briefly explain.
First off, I found G05 at Pep Boys. It doesn't seem to be stocked at AutoZone or Kragen anymore.
The green coolant that your car was built with (commonly called "conventional green") is ethelyne glycol (as are most coolants) as the main ingredient. Ethelyne glycol mixed with water has problems, especially in that it is corrosive to metals. To prevent that, additives are used to overcome the problems. The additive package in "conventional green" is mostly phosphates and silicates and it is heavy in each. Phosphates don't like hard water and is a bit abrasive on pump seals. Silicates fall out of suspension after time and leave a bit of gunk behind in the cooling system and are even rougher on pump seals. "Conventional green" truly needs to be changed fairly often to prevent fall out as well as once the additives are depleted allowing system corrosion.
The next big advance in coolant chemistry was OAT (organic acid technology) which replace both phosphate and silicate. The most commonly known of these is Dexcool. Dexcool is truly a superior coolant but it is not faultless. OAT in general doesn't seem to protect against cavatation in the same way as phosphate or silicate. OAT takes longer to build the protective layer than the other two. The OAT group that GM uses (made by Texaco) for their Dexcool is different from what Prestone uses, although it still meets GM's specs or it could not be call Dexcool. The GM (Texaco) Dexcool has a problem if allowed to run too low for very long and rust forms in the cooling system. This seems to be less of a problem with Prestone's Dexcool. As long as Dexcool is kept at the proper level and proper concentration, it is vastly superior to "conventional green" in that it doesn't have problems with hard water and doesn't have silicate gunky fall out and doesn't have abrassive material that damages pump seals. Dexcool is orange in color.
Ford and Chrysler have responded to the improvements with Zerox (Valvoline) G05. G05 is considered a hybrid coolant because it is OAT with low levels of both phosphate and silicate. It is also called HOAT (Hybrid OAT). The Chrysler stuff is (of all things to lead to confusion) orange. The Ford stuff is yellow. The G05 packaged by Zerox is sometimes nearly clear or slightly yellow.
Something similar to this has been used in europe for a while. It is a little hard to catagorize easily though. The maker of the coolant additive packages is mostly BASF, the German chemical company. BASF has a very long list of additive packages. Europeans like little or no phosphate because in general the water in europe is very hard. The stuff used by VW, AUDI, Mercedes, and Volvo is thought to be G05 or something very close to it.
The Japanese like coolant with no silicate and high in phosphate. They feel that a heavy dose of phosphate does the best for protecting against cavatation. Toyota Red is the best example of this. Even green Japanese coolant is high in phosphate and has little or no silicate. The newest formulations seem to be OAT but still with a dose of phosphate and they still avoid silicate.
Now we get to the newest Prestone product that claims to be for "any make, any year". It seems to be identical to Prestone Dexcool, without the orange dye. It is green or yellowish green. By not declairing that it is Dexcool, they don't have to pay royalties to GM.
Which one can be used with which cars? Even the experts don't agree. To err on the side of caution, the general feeling is that you should use whatever the car originally came with. That is getting harder and harder to do, especially since "conventional green" is getting scarce.
It is my personal opinion that you can use any of them as long as you change it at least as frequently as that coolant calls for. I have used Dexcool (Texaco) in the SVT since it was a year old. I change any colant once a year (it's cheap if you do it yourself). The Escape came with Ford G05 and I changed it and replaced it with Zerox G05 when it was a year old.
Sorry for the brain dump. Maybe this has been helpful.
