Fleetguard Coolant and filters

How to choose the correct type of Engine Coolant?

The questions most people ask are “What colour should engine anti-freeze be, orange, green or a different colour and is the engine coolant the same as antifreeze?”  Engine coolant also known as antifreeze is mixed with water to stop the engine coolant freezing in extreme cold.  The other purpose of using anti-freeze is to raise the boiling point of water assisting engine cooling in extreme heat.  There are many different types of coolant, it is important to know which product is correct for your vehicle application.

IAT Coolant

The most common product is the IAT formula which stands for Inorganic Additive Technology. This product has been used for decades and has proven to give excellent corrosion protection.  The Valvoline product for the IAT antifreeze is ZEREX original green.

DEX – Cool Coolant

Another quite common antifreeze is called Dex-cool.  This product is approved for the use in GM products and the Valvoline product is ZEROX Dex Cool.

The coolant for older engines which allows chemistries old and new to work together is marketed as Maxlife, this product helps to extend the life of a higher mileage engines.

The Colours of Antifreeze

Antifreeze does come in different colours and these colours have some significance, the most common is green although Dex-cool is orange.


Under no circumstances should theses coloured antifreeze be mixed as they are different chemicals as can be seen on the chart below.

Tyre Inhibitor


ZEROX Vehicles Colour

IAT (Inorganic

Additive Technology)




Zerex Original


Older Vehicles




OAT (Organic Acid Technology)


Organic Acids


Zerex Dex-Cool






HOAT (Hybris Oat)


Silicates and Organic Acids




Ford Chrysler, European






HOAT (Hybrid OAT phosphate free)


NAP Free




BMW. Volvo, Tesla, Mini + others




P-HOAT (Phosphated Hoat)


Phosphates and Organic Acid


Zerex Asian Vehicles


Toyotas, Nissan, Honda + other Asian vehicles




SI-OAT (Silicated Hoat)


Silicates and Organic Acids


Zerex G.40


Mercedes-Benz, Audi, Porsche + others



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