Antifreeze Vs Coolant – What Is the Difference Between Them?

In this article, we’re going to answer all the questions you may have concerning antifreeze vs. coolant.

Below, you’re going to learn what distinguishes coolant from antifreeze and if they are indeed different or just the automotive versions of Pepsi and Coke, i.e. different by name but almost identical by nature. 

You’ll also become familiar with the ingredients these products are made of, what antifreeze looks like, and the purposes both coolant and antifreeze serve in your car.

What Is Antifreeze?

Antifreeze is an essential part of your car’s cooling system. It works to regulate the temperature inside your car’s engine as it runs, helping to prevent the liquid freezing in cold temperatures and evaporating when the engine is working hard or in hot temperatures.

The majority of brands consist of one of two active ingredients: ethylene or propylene glycol. Most products will also contain additives, and some are pre-mixed with distilled water, (though coolant is never water alone!)

So what are ethylene and propylene glycol?

Ethylene Glycol is a naturally odorless and colorless alcohol that has a freezing temperature of 8.6 degrees Fahrenheit and a boiling point of 388 degrees Fahrenheit.

When mixed with water, it can increase the liquid’s boiling and freezing temperatures. It isn’t harmful to metal components and doesn’t degrade quickly.  All of these qualities make it useful for use in cooling systems. Unfortunately, though, ethylene glycol is highly toxic.

Propylene Glycol is colorless, odorless, and tasteless. It’s a synthetic liquid that has many industrial applications. For instance, it’s used to manufacture certain polyester compounds.

This syrupy fluid isn’t as hazardous as ethylene glycol. It also has a higher boiling and freezing point. These are 370°F and -74°F respectively.

Helpful Additives

Additives are compounds added to a product to improve how it works. They can be found in motor lubricants, paints, fuel stabilizers, and more.

In antifreeze, additives play several roles. For example, they can inhibit corrosion to protect your car’s inner workings, or delay the inevitable breakdown of the fluid, extending its lifespan and time between top-ups or changing. Antioxidant-based additives help to clear debris that builds up in the coolant system.

What Is Engine Coolant?

Engine coolant is typically a mix of distilled water and antifreeze. The ideal ratio is half and half, although this can change based on your car’s needs.

You may need a higher ratio of antifreeze to water if you have brutal winters. This will prevent the water from freezing in the bitter cold.

It isn’t advisable to use exclusively water-based coolant. This is because water is not as adept at regulating temperature as ethylene and propylene glycol.

Is Coolant the Same as Antifreeze?

For most intents and purposes, the answer to this most common antifreeze/coolant question is yes. Referring to them interchangeably isn’t like confusing diesel with gasoline.

You could say that antifreeze is an ingredient of a coolant mixture when it’s mixed with water, either distilled or tap water. However, this is only if you want to be extremely specific. The two are more or less the same thing. However, the brands, types, and mixtures will vary from brand to brand, and which to use will vary from car to car. 

What Does Antifreeze Look Like?

All the best antifreeze manufacturers use dye. Vivid dyes enable us to spot if there’s a leak, so it’s also easier to ensure accidental spills are thoroughly cleaned up and any antifreeze is disposed of correctly.

You can buy one of three types. Your options are inorganic acid technology (IAT), organic acid technology (OAT), and hybrid organic acid technology (HOAT).

Green (IAT)

Most green brands are made with inorganic acid technology (IAT). They’re rich in silicates (a corrosion inhibitor) to prevent vulnerable metals in the radiator, water pump, and cooling system rusting (and expensive repairs!).

These are best for cars manufactured no later than 1990. The silicates are beneficial for radiators made of copper, aluminum, and brass. 

Pink, Orange, Dark Green (OAT)

These colors tend to represent organic acid technology brands (OAT). They can come in a rainbow of colors except for neon or light green.

This is to prevent them from being mistaken with traditional IAT products at first glance. 

OAT antifreeze doesn’t contain silicates. Instead, it’s packed with additives to improve performance. Common varieties include corrosion inhibitors and other compounds to extend lifespan.

Yellow and Orange (HOAT)

Hybrid organic acid technology (HOAT) is a mix of OAT and IAT antifreeze. These brands are made with silicates but are also formulated with additives.

HOAT brands are often found in major vehicle manufacturers like Mercedes Benz or Chrysler.

What Does Antifreeze Do?

There are a couple of things antifreeze does, most importantly it regulates temperature and shields metal engine components from rust.

If you want to know how the whole system works, watch this video.

Dissipates Heat

The engines in our vehicles run hot. Average operating temperatures can range from 195 to 220 degrees Fahrenheit.

The coolant fluid helps dissipate heat by running through the cooling system in a loop, flowing through the engine block and heater core and radiator before starting all over again. In turn, this reduces overheating and heat-based wear on engine components. 

Prevents Freezing

The name says it all, it stops your engine from freezing solid. As we’ve established, propylene and ethylene glycol have low freezing points.

Reduces Corrosion and Prevents Sediment Build-Up

The additives in coolant protect metal pipes and mechanisms from corrosion.

Certain brands also contain additives to break down debris and sediment buildup that can cause rust in your vehicle over time.

Final Thoughts

The next time you find yourself in a discussion on the difference between coolant and antifreeze, you should now be prepared and able to clear up any misconceptions your friends or family may have.

Do you have any questions or feedback you think we should hear? Please do tell us in the comments below, we’ll make sure to get back to every one of you!