Engine Coolant 101 The Right Coolant for Your Vehicle

AAA Auto Repair Article
By AAA Automotive
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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, it raises the boiling point of the cooling system in summer, and it 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.

(Image: AAA)
Why it’s Important to Have the Right Engine Coolant

In older cars, engine cooling systems were mostly brass, rubber parts and cast iron, so engine coolants were all pretty much the same. These days, automobile cooling systems have parts made from copper, silicon, nylon, steel, and magnesium and aluminum alloys. The type of coolant required by your vehicle can now 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.


What are the Different Types of Engine Coolant

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:

• IAT – Inorganic Additive Technology
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.

• OAT – Organic Acid Technology
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.

• HOAT – Hybrid Organic Acid Technology
Providing the benefits of both IAT and OAT coolants, HOAT coolants are primarily orange and yellow and are common in Chrysler and Ford vehicles. OAT 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.

• Hybrid and Electric Vehicle Cooling Systems
Most hybrid and electric vehicles have a separate cooling system for the battery pack. Only coolants that meet the automakers’ specifications should be used in these systems.

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 that the coolant used meets factory requirements.


Things to Remember

Here are a few other points to remember when it comes to your engine coolant choice:

1. Coolant type cannot be accurately identified by color. Both OAT and HOAT are often orange or yellow, so they can be easily misidentified.

2. 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.

3. Just because a vehicle had one type of coolant when it left the factory doesn’t mean a different type of coolant wasn’t installed at some point in the life of the vehicle. When changing back to the factory recommended coolant, a complete cooling system flush should be performed first.

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