Choosing the Right Coolant for Your Car (2024)

Checking up on your coolant is easy to forget, but an engine’s coolant is just as important as oil when it comes to your car. Coolant does raises the boiling point of the cooling system in summer, lowers the freezing point in winter, and protects the engine and cooling system from corrosion. These functions keep the engine from overheating or freezing when driving in extreme climates.

Coolant needs changing because chemicals in the coolant break down and become less effective over time. This use ends up generating rust and sludge, which can damage the cooling system. If the cooling system becomes damaged, you risk the possibility of the engine overheating–a much costlier mistake than paying for a coolant flush.

Finding the Right Fluid

When it comes time to top off or do a complete system flush you’re going to have to find the right coolant for the job. It would be convenient if every manufacturer used the same coolant, but they don't. There are three main types of coolant that car companies use: Inorganic Additive Technology (IAT), Organic Acid Technology (OAT), and Hybrid Organic Acid Technology (HOAT).

Typically, older cars use IAT. It needs to be changed every two years or 24,000 miles, making it far inferior to newer formulas. One of those newer formulas is OAT. General Motors vehicles use this formula and normally require a change after five years or 50,000 miles. Finally, HOAT is a derivation of OAT that requires the same time change interval unless otherwise specified.

The easiest way to make sure you’re getting the right coolant for the job is to go to your car’s dealership. They’ll sell the coolant for your specific make and model, and it’s guaranteed to be the correct one. Many times, the coolant is actually branded for the car you’re going to put it in.

For example, Honda sells its Type 2 Antifreeze/Coolant in all its dealers. Plenty of others like BMW and Volkswagen do the same thing.

Not every manufacturer does this though. All GM cars use something called Dex-Cool from the factory. Ford meanwhile, uses Motorcraft.

One thing to keep in mind with nearly every modern jug of coolant you’ll come across: They’re all pre-diluted. Years ago coolant was always sold as pure coolant, and you'd have to dilute the fluid yourself with water. The pre-diluted stuff is more convenient of course, but you end up paying a lot more for less coolant.

Going Colorblind

In addition to the OE options, auto parts stores will carry several different aftermarket brands of coolant. Companies like Prestone, Pentafrost, Peak, and others all offer versions that they say work for specific brands or countries in general (the country a car is made in is typically a good predictor for which coolant type it takes).

These aftermarket options are cheaper than OE a lot of the time, but it’s worth grabbing true OE coolant designed for your car.

But what about different colored coolants?

The truth is, color is not a reliable predictor for what type of coolant you have. For example, OAT coolants are usually orange, yellow, red or purple. HOAT coolants are orange and yellow for the most part. Then the older IAT coolant is green. Coolants that manufacturers sell can confuse matters even more, like Honda’s blue coolant.

That's why you need to read what the bottle says and and not rely specific color you’re pouring. If the the bottle's description has you tripped up, check your owner’s manual for the right kind of coolant.

But none of this helps if you forget the process in a few years time. So keep notes on the coolant you used and when, so you're prepared when your engine inevitably needs flushing a few years down the road.