Green: ethylene glycol
Pink: propylene glycol
GM vehicles use the pink.
I haven't confirmed, but heard it's not good to mix the two.
First color is not a reliable indicator of the chemical makeup of the coolant. If you are lucky the label will specify the particulars but even that can be iffy.
Propylene glycol can be added to ethylene glycol but doing so will raise the freezing point of the mix. Propylene glycol is also less effective in transferring heat. The main advantage of propylene glycol is it is far less toxic to animals.
Kubota specifies the use of
ethylene glycol extended life (5yr/150K miles) coolant (HOAT/OAT) in their equipment. It does not matter what color it is. Personally I have been using Prestone Corgard ELC which is yellow. I also have some Peak ELC on the shelf which is blue. Old style IAT coolant (almost always dyed green) should be avoided.
Edit: I forgot to mention the Delo ELC I purchased last year. Chevron bills it as a CAT EC-1 compliant coolant and it is dyed red. It is a silicate free ethylene glycol coolant formulated using Nitrited Organic Acid Technology (NOAT). Claimed service life is 15,000 hours or 8 years.
Dan