Different manufactures of coolant have different colors. The key is the
base make up of the coolant. There are 2 basic groups.
Ethylene-Glycol: This is the basic coolant. It is good for 1-2 years.
Organic Acid: Some manufactures say this is good for life or 500,000 miles
or...... That is great if you don't have a problem (leak, exhaust gases in
coolant, ect). This come in two types NOAT and OAT (with nitrites and
without), this depends on the engine and the amount of aluminum in the
engine components). If this coolant gets mixed with Ethylene Glycol (EG),
the entire system needs to be treated as if it is 100% EG. In other words,
it is NOT good for life.
You will here other terms like Propylene Glycol, this is sold as an
environmentally friendly coolant but it does not cool as good as EG.
I have attached our Coolant Selection document for addition reading or
forwarding to friends with questions.