Are Coolant and antifreeze the same thing

Understanding the Distinction Between Coolant and Antifreeze

The terms coolant and antifreeze are often used interchangeably. But they’re not the same. In this article, we’ll delve into the differences between these two fluids and understand their significance in keeping our vehicles running smoothly.

Defining Coolant and Antifreeze

Coolant and antifreeze are both fluids utilized in an automobile’s cooling system, but they serve different purposes.

What is coolant?

Coolant is a 50:50 mixture of water and concentrated antifreeze. The coolant and antifreeze mixture helps regulate the temperature of the engine by carrying away excess heat. In addition, the mixture lubricates the water pump and prevents cooling system corrosion.

What is antifreeze?

Antifreeze is a concentrate that must be mixed with de-ionized or distilled water to be used in an engine. It can’t be used in its concentrated for. Here’s why. Water is far more effective at removing heat from the engine than antifreeze alone. But using water in the engine causes corrosion and it freezes in cold weather. Freezing can destroy the engine and corrosion can cause leaks in the radiator, heater core, as well as reduce cooling. So water should never be used without antifreeze.

What is antifreeze made of?

Concentrated antifreeze consists of approximately 95% mono or polyethylene glycol and 5% anti-corrosion additives. Older Inorganic Acid Technology antifreeze (IAT) used silicates and phosphates to prevent corrosion. They worked quickly to coat all metal components with a non-conductive film. But IAT antifreeze has a short life of only 2-years or 24,000 miles. The downside to silicate, is that it can be somewhat abrasive and wear out water pump seals. Since car owners often neglect maintenance, carmakers developed longer lasting antifreeze formulas to prevent damage to the cooling systems

Organic Acid Technology (OAT) prevents corrosion on metal parts with an acid that bonds with the metal on a molecular level instead of a topical film. The molecular bond lasts much longer than the topical film, which is why OAT coolants can last as long as 5-years or 100,000 miles. The downside to OAT coolants is that it takes a while to form the protective barrier. That’s why some carmakers switched to Hybrid Organic Acid Technology (HOAT) coolants.

HOAT coolants use the same acids to bond on a molecular level but add a low dose of silicate or phosphate to quickly form a topical film to protect metal surfaces until the acid and bond on a molecular level.

Coolant and antifreeze — how it’s sold

Coolant is usually sold in a 50:50 diluted form and can be added to the cooling system without any further mixing. Concentrated antifreeze should never be added to a cooling system. A 50:50 concentration is the ideal mix for most winter conditions. If you add concentrate to “top off” a system that’s filled with a 50:50 mix, you’ll change the ratio of antifreeze to coolant. That will give you a higher concentration of coolant which yields greater freeze protection. But it also decreases the coolants ability to remove heat.

So you’d be protected against freezing in winter at the expense of overheating in summer.

If you need to top off your coolant, always use a “pre-mixed” coolant that doesn’t need mixing with water.

Mixing different types of coolants

Mixing different types of antifreeze can be detrimental to a vehicle’s cooling system. Incompatible antifreeze formulations can react with each other, leading to the formation of sludge, clogs, and reduced heat transfer capabilities. Therefore, it’s crucial to stick with the type of antifreeze recommended by the vehicle’s manufacturer.

Furthermore, some modern vehicles come equipped with extended-life antifreeze, which can last for several years before needing replacement. Mixing this type of antifreeze with traditional, shorter-life formulations can compromise the overall performance and longevity of the cooling system. To ensure proper function and longevity, it’s advisable to follow the manufacturer’s guidelines and use the recommended antifreeze type.

©, 2023 Rick Muscoplat