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Are antifreeze and coolant the same thing? Should engine coolant be orange, green or a different color? This article will help answer these questions and more.

What Is Engine Coolant?

Engine coolant, also known as antifreeze, is mixed with water to keep the radiator from freezing in extreme cold and overheating in extreme heat. There are many different types of coolant, so it’s important to know what variety is right for your car or truck.

Different Coolant Types

Different vehicles require different coolants. There are varieties for every type of vehicle, from diesel engines to American, Asian and European vehicles. Each one is specifically formulated to keep its designated engine type running in extreme temperatures. It’s important to know the differences so you get the correct antifreeze for your vehicle.

IAT Coolant

The most common variety of liquid antifreeze is an IAT formula, or Inorganic Additive Technology. ZEREX™ Original Green is an IAT coolant that has been used for decades and is a formula proven to provide unsurpassed corrosion protection.

Dex-Cool™ Coolant

Another common antifreeze formula is Dex-Cool®, a coolant formula approved for use in GM vehicles. An option like ZEREX™ Dex-Cool Antifreeze/Coolant, is automaker-approved and meets or exceeds multiple industry specifications.

Coolant for Older Cars

Since coolant technology has evolved so much in the last few decades, if you own an older vehicle you need a formula with a special additive to allow chemistries old and new to work together. MaxLife™ Antifreeze/Coolant helps extend the life of higher mileage vehicles with the additive AlugardPlus®.

The Colors of Coolant

You might be thinking, “What color is antifreeze? What color is Dex-Cool®?” It’s true, coolant liquid comes in different colors, most commonly green (orange for Dex-Cool®). Each color is a unique formula that should not be mixed. The below chart will help you decipher which fluid is in your vehicle. Reminder, you can often find the recommended type of coolant in your vehicle’s owner’s manual.

IAT (Inorganic Additive Technology) Silicates Zerex™ Original Older Vehicles


OAT (Organic Acid Technology) Organic Acids Zerex™ Dex-Cool® GM, Saab, VW


HOAT (Hybrid OAT) Silicates & Organic Acids Zerex™ G-05™ Ford, Chrysler, European


HOAT (Hybrid OAT, Phosphate-free) NAP Free ZEREX™ G-48 BMW, Volvo, Tesla, Mini, others


P-HOAT (Phosphated HOAT) Phosphates & Organic Acids ZEREX™ Asian Vehicle Toyota, Nissan, Honda, Hyundai, KIA & other Asian vehicles PINK / BLUE
Si-OAT (Silicated HOAT) Silicates & Organic Acids ZEREX™ G-40 Mercedes-Benz, Audi, VW, Porsche, others