Many drivers understand that their vehicle requires coolant, but some drivers aren’t sure which type to use—or what coolant is in the first place.

Much like oil, coolant serves the basic function of transferring heat and adding antifreeze protection. Depending on your type of vehicle, you may need a coolant with specialized additives, a coolant formulated for specific manufacturers, or a coolant designed for high-mileage cars.

What Does Coolant Do for My Engine?

The primary purpose of coolant is transferring heat and preventing engine damage caused by freezing or boiling. Heat can only be effectively transferred with a liquid in the system, so it’s crucial to keep your coolant from freezing or evaporating.

Additionally, if coolant boils, the vapors formed do not transfer heat well, which means the engine metal can actually melt if the coolant isn’t kept in contact with certain places that need to stay cool. Some modern vehicles are made with tight engine compartments that don’t feature good air flow, which means they could overheat in a matter of minutes without a functional cooling system.

Coolant also serves the purpose of protecting metals and non-metallic elastomers (like rubber and plastic parts) in the engine and the cooling circuit.

What Sort of Issues Are Caused by Using the Wrong Coolant?

Without the proper coolant in your system, corrosion and component damage can lead to long-term effects. They’re sometimes latent, meaning it takes up to a year for corrosion damage, deposits, and plugging to cause a problem.

This is often misidentified by drivers as a radiator failure rather than simply acknowledging that the wrong coolant was used. If a radiator ends up badly corroded or full of plugging internal deposits, a malfunctioning coolant system is a likely cause.

“Oftentimes, people don’t think about the longer-term effects of corrosion and component damage,” says David Turcotte, Valvoline™ Technical Director. “Those can be latent: it can take six months to a year to get enough corrosion damage, deposits and plugging to create an issue from using the wrong coolant to have a visible problem. And by the time you get that problem, people have forgotten that they used the wrong coolant and think the radiator has simply failed as a part.”

And because coolant-related problems happen inside the motor, you might not realize the damage being caused unless you look at the cooling passages and the internal heat-transfer surfaces of the engine.

How Often Do I Need to Change the Coolant in My Vehicle?

The amount of time between coolant changes has been steadily increasing as engine technology improves.

As recently as two decades ago, changing your coolant every two years was the standard recommendation. Then, about a decade ago, that span increased to five years. In many of today’s modern vehicles, a cooling system is designed to allow up to 10 years (or up to 200,000 miles) before adding new coolant. In fact, some vehicles are filled for life.

Zerex™ Antifreeze by Valvoline was developed to last longer than universal coolants, which not only helps you protect crucial engine parts like gaskets and elastomers, it can lead to an improved lifespan for your vehicle and a reduced cost of ownership for you.

All vehicles aren’t made the same way—there are different materials of construction, different operating environments, different variable flow rates, different peak temperatures and pressures, different elastomers, different non-metallics and gaskets, you name it.

But the one thing they all have in common is that they need to be protected. The OEM of your vehicle does extensive testing to determine what fluids, including coolants, should be used in the systems they’ve developed.

How Do I know Which Coolant to Buy?

It’s crucial to pick the right coolant for your car, so once you’re ready to find the right product for your, read on with our Coolant 102.