The rainbow-like array of colors, pre-mix ratios and dilutions, additives, and more can make selecting or even understanding the various types of antifreeze available today confusing. Choosing the right antifreeze or coolant for your vehicle is essential for a healthy engine and a well-performing cooling system. With various formulas, colors, mixtures, and temperature specifications, not all antifreeze is created equal. Read on to discover why antifreeze is different colors, the differences in antifreeze colors and types, and whether coolant and antifreeze are the same thing.
Why Does My Car Need Coolant?
The purpose of coolant or antifreeze is to cool down your engine and protect it from damaging contaminants, mineral deposits, corrosion, and freezing or boil-over. Designed with a freezing point lower than water, coolant helps engines maintain a safe and stable engine operating temperature for better performance and improved vehicle health. Insufficient coolant levels or contaminated coolant can make your vehicle more susceptible to engine damage, corrosion, and clogs, and could also be one of the reasons your car overheats. To avoid reduced performance and internal engine damage, it’s recommended that you check your antifreeze levels at each oil change or consult your owners manual for more specific coolant replacement intervals. The next step to maintaining a healthy cooling system and efficient vehicle is to know which type of coolant is right for your car. Keep reading to learn the differences between types of coolant and what option may be best for your vehicle based on its age, your driving habits, and the operating climate.
Do It Right: Coolant vs. Antifreeze
Although the terms are used interchangeably, coolant and antifreeze are fundamentally different. Coolant is a mixture of antifreeze and water, whereas antifreeze is a pure mixture of either propylene glycol or ethylene glycol. Antifreeze should always be diluted with water, which is why pre-diluted or 50/50 antifreeze exists to help you achieve an accurate coolant mixture each and every time. Whether it’s antifreeze or pre-mixed coolant you’re looking for, all vehicles need proper cooling system performance to prevent engine damage and performance problems.
What Are The Different Types of Antifreeze?
Coolant has changed over the years in a few different ways — whether it’s the color, concentrates, additives, or updated formulas to match today’s engine demands, there are four general types of antifreeze for vehicles. Whether you have a domestic, Asian, or European vehicle, it may require a specific coolant type that is compatible with the engine and helps protect internal systems from damage. While antifreeze in the past was either green or yellow, it can now come in a variety of colors that aren’t completely indicative of the correct choice for your specific vehicle. No matter what type of coolant your car needs, understanding the differences between the types of coolant can help you make a more informed decision that isn’t based on color alone. Read below to learn more about the four types of antifreeze: Inorganic Acid Technology, Organic Acid Technology, Hybrid Organic Acid Technology, and Nitrite Organic Additive Technology.
Inorganic Acid Technology (IAT)
Known as traditional antifreeze or Inorganic Acid Technology coolant, IAT coolant is used in vehicles made before the 1990s. Usually a neon green color, IAT coolant includes phosphate and silicate inhibitors to prevent oxidation within an engine’s water channels. With older cast iron and aluminum engines, preventing corrosion was one of the primary tasks of coolant, and IAT coolant is designed to ward off scale buildup, corrosion, and rust. The corrosion inhibitors in IAT antifreeze make it a unique coolant mixture that can help prevent damage to the heater core, water pump impeller, or the engine-facing side of the water pump. IAT coolant can typically last up to 2 years or between 24,000 and 30,000 miles, whichever comes first, but it is usually best to follow your manufacturer’s coolant flush and refill specifications found in your owners manual.
Organic Acid Technology (OAT)
Organic Acid Technology (OAT) coolant was created for a longer coolant life in cars manufactured beginning in the 2000s, and commonly comes in green, purple, yellow, red, and orange varieties. OAT coolant may have corrosion inhibitors such as phosphate, borate, nitrate, or silicates that are professionally mixed to extend the coolant’s lifespan and performance. Depending on the OAT mixture, the types of corrosion preventatives will not only keep your coolant performing its best for a longer period of time, but can help prevent engine damage from rust buildup, optimize cooling system performance, and limit the risk of an overheating car. In short, OAT coolant is designed to eliminate more frequent coolant flushes associated with IAT or conventional coolant while still adequately protecting your engine. OAT coolant should be flushed and replaced every 5 years or 150,000 miles, but ensuring that you adhere to your vehicle manufacturer’s recommendations, or those of the coolant manufacturer, can help guarantee the best possible performance.
Hybrid Organic Acid Technology (HOAT)
Hybrid Organic Acid Technology (HOAT) is the most recent coolant engineering advancement, and is made for light- and heavy-duty modern vehicles to improve upon OAT technology. HOAT coolant is a hybrid of OAT coolant that includes more silicate additives to ward off scale buildup, rust, and corrosion that can cause serious engine damage. Although it has the same coolant service interval as OAT coolant, HOAT amplifies OAT’s additive properties with extra organic and inorganic additives for longer-lasting coolant life. Often seen as the ‘perfect mix’ for coolant, HOAT should be changed every 5 years or 150,000 miles and is most commonly found in orange and yellow varieties.
Nitrite Organic Additive Technology (NOAT)
Designed for heavy-duty applications, Nitrite Organic Additive Technology is OAT coolant with the addition of organic additives as well as a nitrite or molybdate liner for pitting and corrosion protection. NOAT does not include silicates as seen in OAT technologies, but is chemically designed for performance in highly-demanding or extreme-temperature engines. Referred to as a lifetime or extended-life coolant, the nitrite that makes up NOAT reduces the need for coolant additives so you can trust that it’s protecting and cooling your heavy-duty engine throughout its lifetime. NOAT coolant should be flushed and replaced at approximately 1,000,000 miles, which most vehicles will likely never see, and is often found in red and orange hues.
What Is Dex-Cool Antifreeze?
If you own a GM vehicle, or if your vehicle uses coolant with the word “Dex” or “Dex-Cool” on the label, understanding what Dex-Cool is can help you better care for your car and choose the right antifreeze mixture to protect your engine. Dex-Cool was the first extended-life antifreeze to be produced in the United States, and can be found factory-installed in GM vehicles manufactured in 1995 or newer. Phosphate additives in Dex-Cool help prevent corrosion and are factory-tested to ensure vehicle compatibility and engine protection. Dex-Cool is an industry standard of trusted coolant mixtures that are also proven to protect against corrosion and internal component damage. Many aftermarket antifreeze options are also Dex-Cool approved, meaning that they are safe and have been approved for use in vehicles that require Dex-Cool coolant.
What Type of Coolant Does My Car Need?
With coolant coming in enough shades to create a rainbow, it can be tough to know exactly what your vehicle needs — even if you know the color of coolant you’re looking for. Be sure to check your owners manual to determine the exact type of antifreeze your vehicle needs. It’s best to only take advice from your vehicle’s manufacturer about the coolant your car requires since the wrong coolant formula can increase the chances of engine damage. If your vehicle came from the factory with a certain color of coolant, do not stray from this type since it is likely the recommended coolant type for your vehicle year, make, and model. It’s important to never mix different antifreeze types since it can quickly cause corrosion buildup within your engine’s water channel, decreased performance, overheating, or worse, a blown head gasket.
Why is Antifreeze Different Colors?
While coolant started out being neon green or yellow thanks to the introduction of IAT coolant, additives and corrosion inhibitors can change the chemical structure of coolant, and thus, its color. Since coolant is extremely toxic, it was initially designed to be bright enough to ward off children or unknowing people from consuming the liquid if it were to leak on the ground. Bittering agents were also added more recently to reduce the risk of animals attempting to consume spilled coolant. With time and developments in technology, coolant is still manufactured to look unappealing, but comes in nearly all colors of the rainbow. Borate, phosphates, silicates, and nitrate have their own set of characteristics, and when professionally mixed to create specific coolant formulations, can result in colors like purple, red, orange, and even green.
Knowing what coolant your car needs to run its best may be overwhelming without the proper understanding, especially with technological updates, the introduction of coolant additives, and an array of available coolant colors. Though understanding coolant formulas can be daunting, O’Reilly Auto Parts and our trusted Professional Parts People® are here to help you choose the best antifreeze or coolant to match the specifications for your vehicle requires and get the job done right. Shop IAT, OAT, HOAT, and NOAT coolant both online and in-store to help maintain a healthy engine that operates at the appropriate temperature. For all of your cooling system repairs and maintenance, you can also find antifreeze testers and bubble gauges, funnels, 50/50 pre-mixed antifreeze, concentrated coolant, and more at O’Reilly Auto Parts. Check out our How-To Hub for helpful content about coolant and cooling system repairs, including how to test antifreeze for winter, the basics of your cooling system, how to flush and fill antifreeze, and much more to help your vehicle run at its best.