Antifreeze Ingredients: What’s In It and Why?

Your car's engine generates heat, and it needs a coolant solution to absorb it. While water can efficiently perform this task on average temperatures, trouble ensues if it drops below zero. That's why we use antifreeze.

Most people add it without thinking twice about the ingredients and their purpose. However, if you're of the curious kind who likes to know how stuff works, you're in luck. 

Today, I'll explain antifreeze ingredients. More specifically, how they keep your engine safe and what to consider during your next purchase.

Antifreeze vs. Coolant

If you've researched this topic, you noticed the terms 'antifreeze' and 'coolant' thrown around almost interchangeably. There's a slight difference.

Antifreeze is a solution that you mix with water before use, in a proportion stated on the manual. Most often, the ratio will be 50-50, but you might want to increase it to 70-30 in harsh winter conditions. Either way, you'll find the instructions on the box.

Coolant is a pre-mixed, ready-to-use combination of antifreeze and water.

How Antifreeze Works

Let's start with the basics. Different fluids have various boiling and freezing points, which depend on the substances within and their concentrations.

Molecules slow down and bind into rigid structures when the temperature is low. 

This process happens fast in a one-ingredient solution. If you add another molecule to the mix, it will stall the binding process. The more ingredients there are, the lower the temperature needs to be for the liquid to freeze.

However, you can't pour anything into your engine. Since we're adding antifreeze to vehicles, it needs to contain substances that don't corrode metal. Moreover, it needs to have a high boiling point, too, to avoid pressure buildups.

What It Does

Okay, Matt, but what does antifreeze DO in my vehicle?

It circulates your engine to halt the rise in temperature. Its anti-corrosive elements prevent degradation of your metallic components. Finally, it slows down bacterial buildup and other organic contamination, extending your engine's lifespan.

Chemical Composition

I've gone through the essentials of antifreeze composition, but that alone doesn't tell you enough. 

Antifreeze is available in two forms when it comes to the primary ingredient. You can get ethylene glycol-based and propylene glycol-based solutions.

The first liquid was the norm until the mid-nineties, and it still comes in the recognizable bright green. However, as new vehicles' advanced engine components require more protection, the rise of the second variation took place.

The primary difference between these chemical elements is their anti-corrosive factor. 

Today, apart from bright green, you can also get antifreeze in red, yellow, orange, and blue. The various antifreeze colors determine the properties, each addressing engine components' specific requirements.

Antifreeze Types

Note that propylene and ethylene are colorless. Manufacturers add colors to the mix later to differentiate the kinds of solutions. In general, these fall into three categories.

Inorganic Acid Formula

IAF is the bright green antifreeze that we all recognize. People with older vehicles still use them, and you'll have to change it once around every two years.

It consists of glycol, phosphates, and a low amount of silicates. It also contains supplemental coolant additives that protect engine lining.

Organic Acid Technology

These solutions are popular with newer cars globally thanks to their anti-corrosive properties and longer lifespans of three to five years. OAT's design assists aluminum and nylon vehicle parts, protecting them from degradation.

OATs use propylene glycol for their foundation, which is less harmful and toxic than the IAF base. You'll most often find these in orange, red, and yellow. 

Hybrid Organic Acid Technology

The third type combines the best of the previous two solutions. It strengthens corrosion resistance for aluminum elements and iron components alike. 

If you use HOAT, you'll need to change the liquid once every five years. They come in many hues and work with most cars made after 2002. There are three sub-variants, silicated, phosphate, and phosphate-free.

Can You Mix Colors?

You might've noticed that color is not the best indicator of the antifreeze type. Even if you know that, for instance, your car needs orange, always read the bottle and your car manual to be sure you're keeping it safe.

It's never a good idea to mix colors, as it will lead to a chemical reaction in your reservoir.

In a Nutshell

Although this supporting content is for those looking to learn more about their cars' inner workings, let me remind you all of one thing.

Always follow the recommendations of your manufacturer. Using the wrong kind of antifreeze, adding too much or too little can cost you a fortune, and it's so easy to avoid.

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