Cooling & Heating

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Buyer's Guide

Coolant Buyer's Guide

Coolant, also called antifreeze, is the fluid that circulates through your engine and radiator to manage engine temperature and protect the cooling system. This guide covers how coolant works, the different types, and how to choose the right one for your vehicle.

How Coolant Works

Coolant is a mixture of ethylene glycol (sometimes propylene glycol), water, and various additives. The glycol allows your coolant system to operate safely across a wide range of temperatures by both raising the fluid's boiling point and lowering its freezing point. Meanwhile, the additives protect the various metal components in your cooling system from rust and corrosion.

Coolant is circulated through your engine by the water pump where it absorbs heat. The fluid then travels to your radiator where it dissipates this heat and the cycle continues. The thermostat regulates when coolant is allowed to flow to the radiator.

Coolant Types

Your vehicle will determine the type of coolant that should be used. Coolant types should never be mixed. There are three main families:

IAT (Inorganic Additive Technology): The traditional coolant, typically green in color. IAT uses silicate and phosphate corrosion inhibitors. Standard on vehicles built before the mid-1990s. Typically lasts 2 years or 30,000 miles.
OAT (Organic Acid Technology): A common long-lasting coolant used in modern vehicles. OAT is silicate-free and phosphate-free. Typically lasts 5 years or 150,000 miles. Comes in a range of colors: orange, red, pink, or blue, depending on the manufacturer.
HOAT (Hybrid Organic Acid Technology): A hybrid between IAT and OAT that offers a long service life and silicates for corrosion protection. Comes in yellow, orange, or blue. Typically lasts 5 years or 150,000 miles.

Note: Coolant color is not a reliable indicator of coolant type. Always confirm the correct coolant by checking your owner's manual or the manufacturer's specification for your exact vehicle.

Never Mix Incompatible Coolants

When incompatible coolants are mixed, they can react and gel into a thick, sludge-like substance that clogs the narrow passages of your cooling system. This can cause your engine to overheat and lead to potentially serious damage. If you don't know what type is currently in your system, refer to your owner's manual before adding new coolant.

Pre-Mixed vs. Concentrate

Coolant is sold in two forms:

Pre-Mixed (50/50): Already diluted to the correct ratio of coolant to water. Convenient, ready to pour, and the simplest choice for topping off or a quick service.
Concentrate: Coolant you must mix with water before adding to your system. More cost-effective and lets you tailor the ratio if needed, but requires mixing. In extreme climates, a 70/30 split of antifreeze and water can be used.

If you mix concentrate yourself, always use distilled or deionized water, never tap water. Tap water contains minerals that can damage the cooling system over time.

Conclusion

Coolant protects your vehicle against overheating, freezing, and corrosion all at once. Always use the exact coolant type specified by your vehicle's manufacturer and never mix coolant types. Choose pre-mixed for convenience or concentrate for a more cost-effective full flush. You can find all the parts you need and plan your build on RideBuilder.

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