What Coolant Does My Car Need?

Most drivers don’t give engine coolant a second thought. It’s just another item under the "check fluids" service included with an oil change. However, engine coolant performs three vital jobs: It lowers the freezing point of the cooling system in winter, raises the boiling point of the cooling system in summer and protects the engine and cooling system from rust and corrosion year round. 

If your car’s cooling system is not topped off or refilled with the correct coolant, expensive problems could result. We’ll guide you through choosing the right coolant for your car, ensuring optimal performance and longevity for your vehicle.

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Engine coolant, commonly referred to as antifreeze, is a mixture of water and chemicals used to prevent your engine from overheating and freezing in extreme weather conditions.

During extreme heat or cold, your engine becomes vulnerable to damage and cracks, causing the check engine light to turn on. Coolant absorbs the heat generated by the engine and transfers it to the radiator to dissipate. Additionally, additives, such as corrosion inhibitors, are included to prevent rusting and lubricate specific parts of the cooling system, such as the water pump.

Many modern automobiles require enhanced engine coolants to properly maintain the vehicle’s cooling system and protect the engine from damage. Today, automotive service providers use three basic types of engine coolant:

For decades, this distinctive green-colored coolant protected cooling systems, but it is rarely used as factory fill in modern cars. One reason is the fast depletion rate of its additives, which means it has to be changed more frequently, usually every two years or 24,000 miles.

Commonly required for vehicles manufactured by General Motors and some other automakers, OAT coolants are not compatible with other types. Usually orange, yellow, red or purple, OAT coolants are typically changed every five years or 50,000 miles.

Providing the benefits of both IAT and OAT coolants, HOAT coolants are primarily orange and yellow and are common in Chrysler and Ford vehicles. HOAT coolants are typically changed every five years or 50,000 miles, although some automakers specify intervals as long as 10 years or 150,000 miles.

In addition to the basic coolant types described above, each automaker has unique requirements for engine coolants. The product used should always meet the applicable specifications. This information is available in your owner’s manual, and a good service technician will always make sure the coolant used meets factory requirements.

The best coolant for your vehicle can vary by year, make, model, engine and even the country where the car was made. With so many factors in play, car owners need to know which type of engine coolant is right for their vehicle. 

The owner’s manual should include a recommended type of coolant for your vehicle's use. It should include the type of coolant to use, like IAT or OAT, and may recommend specific brands to purchase from. Using the recommended coolant for your vehicle is crucial to avoiding engine damage. 

If the owner’s manual doesn’t include brand recommendations to choose from, you’ll need to spend time researching coolant brands on the market. A good brand should have the following attributes:

If you’re still unsure of a coolant brand, it’s best to consult a certified technician who can provide coolant recommendations for your vehicle.  

Follow the instructions on the bottle when replacing the coolant in your vehicle. Some may be "premixed," meaning the chemicals are already mixed with water, while others require dilution with water before being added to the radiator. Failure to follow the instructions may cause damage to your engine and other issues in the cooling system.

While different coolant types can sometimes be associated with specific colors, it's not the most reliable method to determine the coolant your vehicle requires. Both Organic Acid Technology (OAT) and Hybrid Organic Acid Technology (HOAT) coolants are often orange or yellow, making them easily misidentified based on color alone. 

If you’ve purchased a used car and are uncertain about the type of coolant your vehicle uses, relying solely on the existing antifreeze color is not advisable. Doing so may lead to using the wrong coolant, potentially causing damage to the cooling system. It's best to consult the owner’s manual for accurate information on the correct coolant type and specifications for your vehicle.

Automakers don’t adopt new coolants on a simple schedule. It’s entirely possible for two vehicles from the same manufacturer to use two completely different coolant types.

Even if a vehicle initially had one type of coolant, it might have been changed at some point. Before switching back to the factory-recommended coolant, performing a complete cooling system flush is essential.

How often you need to replace your coolant depends on several factors, including your vehicle's make and model, manufacturer recommendations and the type of coolant used. Generally, coolant should be changed every 30,000 miles or two years, whichever comes first. However, you can consult the owner’s manual to determine how often your vehicle needs to be serviced. 

One great way to ensure you get the right coolant to keep your vehicle running smoothly is by having your vehicle maintenance performed at a AAA Approved Auto Repair facility.

 AAA has inspected and approved 7,000 shops in North America, so it’s easier than ever to find an auto shop near you. Don’t forget that AAA Roadside Assistance is available in case of car trouble and can provide timely service as needed.