What are the differences between different colored coolants (excluding DexCool)?

What is coolant?

Coolant (sometimes referred to as antifreeze or radiator fluid) is used to regulate your engine temperature and prevent it from overheating.

Are pink and orange coolant the same?

Dexcool is not the only brand name that is long life antifreeze. Other antifreezes could also be orange or red (pink) in colour. If an owner’s manual tells you the coolant should be changed in 5 year cycles then your engine has the long life type. If it is a two year cycle it will be the standard type.


Why You Should Never Mix The Coolants

Each type of coolant has its own formula made specifically for certain cars. Adding the wrong kind of coolant or topping off the reservoir with a different kind of coolant will affect the engine in a variety of ways.

For example, adding an OAT coolant to an older engine that requires the standard IAT green coolant will dilute the stuff the engine really needs – phosphates and silicates. As a result, the metal in your engine won’t get the protection it needs.

Three Types Of Coolants

There are three common types of coolants available in the market:

  1. Inorganic Acid Technology (IAT): This old-fashioned green coolant used for decades is still around because some older cars require it. It contains chemicals that prevent copper brass, cast iron, and aluminum cooling system components from deteriorating. This type of coolant is not recommended for newer cars.
  2. Organic Acid Technology (OAT): Usually orange or yellow, this type of coolant lasts longer and is used in some newer engines where metal protection isn’t required. It is propylene glycol-based and does not contain silicates or phosphates. Because of that, OAT coolants act slow and don’t protect exposed metal as much as IAT coolants do. GM’s DexCool is a leading brand for OAT coolants and comes in an orange color.
  3. Hybrid Organic Acid Technology (HOAT): Many auto manufacturers dislike the fact that OAT coolants don’t protect exposed metal as well as IAT coolants do, but they still like that OAT coolants last longer, are safer to use, and are more environmentally friendly. They came up with a solution: HOAT. It’s a hybrid of IAT and OAT that’s basically OAT coolant with a small number of silicates. It contains the best of both worlds. This type of coolant is marketed under several different names, the most common ones being:
    • G-05 (most European auto manufacturers)
    • G-11 or G-12 (Volkswagen and Audi)
    • Global (most coolant manufacturers)

Watch for signs of oil or rust

The color of healthy engine coolant is green (for ethylene glycol) or orange (for Dexcool). A rusty color indicates that the rust inhibitor in the coolant has broken down and it can no longer control rust and scale buildup. The system must be cleaned/flushed and a fresh 50/50 mix of coolant installed to restore integrity. A milky color indicates the presence of oil in the system. This is not good; it usually means that a head gasket, intake manifold, or transmission oil cooler is leaking oil or transmission fluid into the engine coolant. This is a deadly mix that will kill an engine or transmission in short order. Address the probleFrim immediately!

Are all green coolants the same?

And you do need at least a 70/30 antifreeze/water mix for the best results. Typically, Valvoline says, coolant comes in green. … These different types of antifreeze all do broadly the same things. They prevent water from freezing and boiling off and inhibit corrosion and mineral deposits in the radiator.


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