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What Is Antifreeze and what does it do for my engine?

Adding antifreeze to an engine in a snowy landscape

You know about oil, washer fluid, brake fluid and transmission fluid — but what is antifreeze? Learn what role antifreeze plays in your vehicle’s performance, what types of antifreeze are available and tips on how to use this vital liquid.

What Is Antifreeze?

Antifreeze is also known as engine coolant. This colorful liquid plays a couple of key roles in engine performance. First of all, antifreeze helps maintain a constant temperature within your car’s engine. It helps prevent the engine from overheating when it’s hot outside, and it makes sure the engine doesn’t freeze during frigid winters.

Secondly, antifreeze helps maintain proper fluid temperature levels in some vehicle systems. It is common for a radiator to also contain a transmission fluid cooler inside it, which also uses the antifreeze to regulate transmission fluid temperatures. There can also be an  engine oil cooler submerged within antifreeze inside the engine itself.

What Types of Antifreeze Are Available?

You can choose from three main types of antifreeze, which are specially created to deliver certain benefits:

  • Inorganic Acid Technology (IAT) is green in hue. It’s designed to extend the life of engine parts and prevent them from wearing down, and it uses a variety of phosphates and silicates to achieve this goal. IAT typically needs to be flushed out and replaced every 30,000 miles.
  • Organic Acid Technology (OAT) comes in a host of colors, ranging from green to orange. Unlike IAT, it contains no phosphates and silicates, which makes it less equipped to provide protection against engine wear. Typically, OAT can last for up to 150,000 miles before it needs to be replaced.
  • Hybrid Organic Acid Technology (HOAT) comes in a variety of hues including orange and yellow. It typically consists of OAT mixed with a corrosion inhibitor. As with OAT, HOAT can last for up to 150,000 miles.

Keep in mind that different vehicles may have different needs regarding the type of antifreeze they require. The owner’s manual may provide information on the best type of antifreeze for your car.

Tips for Using Antifreeze

When using antifreeze, it’s important to remember that it should never be applied straight; it always needs to be diluted with water. With most vehicles, you need to mix antifreeze and water in a specific ratio to get the desired results. During the cold winter months, a ratio of 60% antifreeze to 40% water is usually required. You may need to change this ratio if you live in a region that is especially frigid, where extreme winter weather requires a ratio of 70% antifreeze to 30% water.

Antifreeze often features ethylene glycol as its main ingredient, but it’s a dangerous poison. Making matters worse, it has a sweet taste, which can make it attractive to small children and animals. If you’re looking for antifreeze that’s less poisonous but functions in the same way, options are available that use propylene glycol instead.

Because many types of antifreeze are available, the range of options can be overwhelming. Knowing a little more about antifreeze can help you confidently choose an antifreeze product for your car that best meets your needs.

Check out all the antifreeze products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on antifreeze, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Flickr.


Warren Clarke View All

I'm a writer and editor who's a regular contributor with the New York Daily News and Carfax, and my content has appeared in over 20 publications. I've written content that covers industries such as automotive, medical, insurance, healthcare, real estate, plumbing, pest control, dental and hospitality.

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