Skip to content
Shop Our Deals Of The Month - Big Savings

What is Antifreeze or Coolant: Difference Between Antifreeze & Coolant

What is Antifreeze or Coolant

What is Antifreeze/Coolant?

Simply put, antifreeze is a fluid mixture that protects motor car engines. Because combusting engines heat up considerably, they need engine coolant to stop them from getting too hot.

Plain engine coolant, such as ordinary water, is widely available and has the ability to transfer heat away from engines.

But it can't get the job done in many circumstances. Adding in antifreeze agents results in a mixture that protects hot engines far better than mere water coolant would without the additives.

Today's antifreeze coolant, a type of engine coolant, does get the job done. When sold in jugs, it’s a thick, odourless liquid, usually with coloured dye added.

It must be handled with respect since, despite its sweet taste, it's often toxic and thus a danger to kids, pets, and others.

Antifreeze as we know it today typically relies on the additive agent called ethylene glycol, first mass produced in 1927.

But innovators have been fascinated with coolant technology for a very long time.

Thousands of years ago, the Romans employed aqueducts to carry heat away from buildings. Hundreds of years ago, inventors tried, with varying degrees of success and failure, to improve on iceboxes by creating vapour-compression techniques for refrigeration.

French chemist Charles-Adolphe Wurtz's work in the mid-19th century on a chemical process now known as the Wurtz-Fittig reaction underpins today's myriad uses of ethylene glycol, including for antifreeze. Wurtz's surname is even inscribed on the Eiffel Tower in Paris in honour of his achievements.

Shortly after mass-production on ethylene glycol began, the motor car industry adopted the chemical compound as the chief antifreeze additive.

Fast forward to the present, and ethylene glycol remains the dominant antifreeze substance. However, inventors are testing new substances for car coolant all the time. Some newer chemical compounds, such as propylene glycol, are already available for use.

Difference Between Engine Coolant and Antifreeze and Antifreeze Coolant?

Difference between Antifreeze and Coolant

These three terms are often used interchangeably, but to be precise, there are important differences between them.


What is antifreeze? The word has two separate meanings. First, the antifreeze product sold in jugs at car parts shops is actually a mixture of various substances. The whole mixture taken together is loosely referred to as antifreeze for convenience.

The second meaning of antifreeze is more specific. This technical meaning refers to the exact chemical compounds primarily responsible for the enhanced protection against engine overheating.

These chemical agents are added along with other substances, such as coloured dye, to create the product sold in jugs at shops. Shops do sell the chemical agents by themselves as concentrated antifreeze for consumers seeking to make their own mixtures.

Related Product: Concentrated Longlife Red Antifreeze


What is coolant? Coolant refers to any substance, typically gas or liquid, that regulates a system's temperature, especially if it turns the temperature down.

But what about engine coolant? The broad category engine coolant encompasses any substances that regulate or turn the temperature down on any engines. For example, some aeroplanes employ air to cool their engines.

Such air serves as engine coolant for these aircraft. But if shoppers ask motor shop mechanics for engine coolant, they’ll understandably direct them to the antifreeze products marketed to everyday auto consumers, namely concentrated antifreeze or antifreeze mixture product.

Related Product: Concentrated Blue Antifreeze & Coolant

Antifreeze Coolant

What is antifreeze coolant? The term antifreeze coolant commonly indicates that of the multiple types of coolant, the kind for car engines is meant.

After all, since air conditioning systems in motor cars overheat too, they also need coolant. But AC systems use refrigerant, a completely different fluid than antifreeze. Motorists should not confuse or attempt to switch the two dissimilar fluids.

Why Do I Need Antifreeze/Coolant?

Why to Use Antifreeze or Coolant

Vehicle engines get very hot during performance. Without engine coolant, these powerful devices would overheat and suffer damage, like a smartphone that overheats frequently.

In the Model T Ford era, prior to World War II, it was normal to try to cool engines with plain water. It didn’t work very well. Auto engines would overheat merely from drivers attempting steep roads!

When ordinary water is used for car coolant, the liquid may get too cold, too hot, or cause wear and tear. If water freezes and expands, it damages the motor car, perhaps by bursting radiator tubes.

If water boils and steams away, the engine is left without coolant and at risk of overheating. If the water contains impurities, that leads to rust eating at the engine metal, or other corrosion or cavitation issues.

Motorists definitely need quality antifreeze mixture to safeguard their hardworking engines against harm.

Once added into water, the antifreeze compounds raise the mixture's boiling point (great for hot weather), lower its freezing point (great for cold weather), and provide inhibitors that prevent wear and tear such as rust.

All this means the enhanced coolant mixture can do its job better than if were just plain water lacking antifreeze additives.

In other words, adding concentrated antifreeze and other helpful substances to water coolant creates antifreeze mixture product that has a far better chance of keeping an engine’s temperature within safe parameters.

Plus, compared with regular water, antifreeze mixture product provides supplementary bonuses like protection against rust. That's the use of antifreeze.

Why do cars need antifreeze? Good antifreeze will ward off not just overheating damage to a motor car engine, but will also ward off the expensive repair bills that would follow.

On the first days of cold seasons, repair services send mechanics out to thousands of homes to help upset motorists. That's because their radiators, cylinder heads, or other car parts have been damaged due to lack of antifreeze.

What is Antifreeze Made Of: Chemistry of Antifreeze/Coolant

Chemistry of Antifreeze and Coolant

Over the years, innovators have experimented with various types of car coolant. Some even tried coolants based on sugar and honey. These old types of coolant didn't work well. It's best to use a current, quality antifreeze mixture product designed knowledgeably.

Water freezes at 0° Celsius and boils at 100° Celsius. Cold weather can easily drop below 0° Celsius and hardworking engines can easily exceed 100° Celsius.

Motorists need an antifreeze agent that prevents their engines from overheating while simultaneously allowing the engines to perform in cold weather.

One of the earliest antifreeze agents added to water, prior to World War II, was methyl alcohol, also known as methanol.

This agent successfully lowered the freezing point of water, stopping the mixture from dangerously expanding on cold days. Unfortunately, methanol lowered water's boiling point as well. Engines boiled the methanol-infused mixture away, leaving themselves unprotected against overheating problems.

Another early antifreeze agent was glycerol. This chemical compound lowered the freezing point of water,  but not low enough.

If weather temperature dropped too low, glycerol couldn't safeguard the coolant from freezing any longer. The motor car industry still needed a "permanent antifreeze" agent suitable for all environments year round.

In 1926, science found the answer: the petroleum-derived chemical compound ethylene glycol. This antifreeze additive, still widely used today, has the chemical formula C2H6O2. That means ethylene glycol is chemically composed of two carbon atoms, six hydrogen atoms, and two oxygen atoms.

Of course, antifreeze mixture product found in jugs at car parts stores likely will contain more than just ethylene glycol. It will also contain water, coloured dye, inhibitors against corrosion, and other substances.

Commercial antifreeze mixtures have myriad formulations. Imagine a consumer product that consists of 50% ethylene glycol and 50% water; imagine a competitor's product that consists of 40% ethylene glycol and 60% water. Formulations become even more complicated once companies add in corrosion inhibitors, dyes of different colours, or other substances.

An antifreeze mixture of half ethylene glycol, half water should have a freezing point of approximately -35° Celsius and a boiling point of around 107° Celsius.

However, factors such as the inclusion of corrosion inhibitors can dramatically alter those points. A motorist should check the jug's label and the car's manual for more precise information specific to their situations.

Propylene glycol is a relative newcomer on the antifreeze scene. One downside is its increased viscosity relative to ethylene glycol, resulting in less efficient heat transfer.

One benefit is propylene glycol's lack of toxicity, meaning spills are less dangerous to curious creatures than spills of ethylene glycol. There are other new antifreeze agents to consider, too, including hybrid organic acid technology. 

What Makes a Good Antifreeze/Coolant

A good first step when selecting engine coolant is to decide between buying a premixed antifreeze product and buying concentrated antifreeze to make a mixture in DIY fashion.

If the latter, the motorist should be sure to carefully follow the manufacturer's instructions provided with the concentrated antifreeze.

If a consumer is selecting premixed antifreeze product, the next step is to pick the right mixture for the car in question.

For instance, some antifreeze coolant contains phosphate inhibitors that work well for vehicles in Asia where heat transfer may be a serious challenge. However, phosphate inhibitors cause problems with the hard water minerals found in Europe.

For drivers in Europe, anti-corrosion inhibitors based on carboxylates and silicates serve the cars better.

To choose the best antifreeze mixture product for a particular car, consult the vehicle's manual, the manufacturer information on the jug label, or an expert.

Previous article What Happens if You Don’t Dilute Screenwash?