For starters just let it sink deep, Antifreeze and Coolants are similar, but not the same. To maintain a functioning cooling system, you will need to use antifreeze and coolant. However, it can be confusing what the terms coolant and antifreeze mean and how they differ from each other, especially since many people use the terms interchangeably. Antifreeze is a concentrated, glycol-based liquid that must be diluted with water before use; at which point it is referred to as coolant. When mixed with water to form coolant, the antifreeze helps to keep engine components free from freezing up and overheating, regulating temperatures to protect the engine from damage and safeguard its performance in hot or freezing weather or at the temperature operating limit of the engine.

An antifreeze is an additive which lowers the freezing point of a water-based liquid. An antifreeze mixture is used to achieve freezing-point depression for cold environments. Common antifreezes increase the boiling point of the liquid, allowing higher coolant temperature. Antifreeze is a chemical additive that reduces the freezing points and increases the boiling points of water-based liquids.

Primary Agents of Antifreeze

Most antifreeze is made by mixing distilled water with additives and a base product of ethylene glycol or propylene glycol.

Ethylene glycol: Antifreeze consists mainly of ethylene glycol, it is used in car’s cooling system to enable trouble-free engine operation even in the most extreme, sub-zero weather. Ethylene Glycol prevents coolant liquid freezing within your radiator by lowering its freezing temperature, alongside lubricating the water pump and inhibiting corrosion. Ethylene glycol solutions were marketed as "permanent antifreeze" because the higher boiling points provided advantages for summertime use as well as during cold weather. They are used today for a variety of applications, including automobiles. When ethylene glycol is used in a system, it may become oxidized to five organic acids (formic, oxalic, glycolic, glyoxylic and acetic acid). Inhibited ethylene glycol antifreeze mixes are available, with additives that buffer the pH and reserve alkalinity of the solution to prevent oxidation of ethylene glycol and formation of these acids. Nitrites, silicates, borates and azoles may also be used to prevent corrosive attack on metal.

Propylene glycol: Propylene glycol is considerably less toxic than ethylene glycol and may be labeled as "non-toxic antifreeze". It is used as antifreeze where ethylene glycol would be inappropriate, such as in food-processing systems or in water pipes in homes where incidental ingestion may be possible. For example, the U.S. FDA allows propylene glycol to be added to a large number of processed foods, including ice cream, frozen custard, salad dressings, and baked goods. Propylene glycol should be replaced when it turns a reddish color. When an aqueous solution of propylene glycol in a cooling or heating system develops a reddish or black color, this indicates that iron in the system is corroding significantly. In the absence of inhibitors, propylene glycol can react with oxygen and metal ions, generating various compounds including organic acids (e.g., formic, oxalic, acetic). These acids accelerate the corrosion of metals in the system.

A coolant is a substance, typically liquid or gas, that is used to reduce or regulate the temperature of a system. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, chemically inert and neither causes nor promotes corrosion of the cooling system. Some applications also require the coolant to be an electrical insulator. While the term "coolant" is commonly used in automotive and HVAC (Heating, ventilation, and air-conditioning) applications, in industrial processing heat transfer fluid is one technical term more often used in high temperature as well as low temperature manufacturing applications. The term also covers cutting fluids. Industrial cutting fluid has broadly classified as water-soluble coolant and neat cutting fluid. Water-soluble coolant is oil in water emulsion. It has varying oil content from nil oil (synthetic coolant). This coolant can either keep its phase and stay liquid or gaseous, or can undergo a phase transition, with the latent heat adding to the cooling efficiency. The latter, when used to achieve below-ambient temperature, is more commonly known as refrigerant.

Coolant is a mixture of antifreeze and water, the ratio of which varies from vehicle to vehicle. Coolant ensures that the water in your vehicle’s radiator system does not freeze in winter, or boil and evaporate in summer. A 50:50 mix of antifreeze and water is the most common – this raises the boiling point of water to between 240°C and 270°C, and lowers the freezing point to around -37°C. It’s important to always use coolant in your car, not pure antifreeze, as antifreeze has a much higher freezing point of around -20°C. Engine coolant is a liquid mixture of water and antifreeze located in your vehicle’s radiator. It prevents your engine from overheating in hot weather and freezing in extreme cold weather, conditions where things can go very wrong for an engine.

What Is the Difference Between Coolant and Antifreeze?

Antifreeze and coolant are not the same thing because the antifreeze is an undiluted chemical additive that has the ability to reduce the freezing point and increase the boiling point of water-based liquids whereas the coolant is a by-product of water and antifreeze most commonly mixed at a 50:50 ratio. When you’re talking about the liquid in your cooling system, you might hear mechanics refer to the liquid inside the cooling system as coolant or antifreeze, or both. That’s because they’re used interchangeably to describe the liquid in the cooling system that helps the engine run at the correct temperature.

The key difference in terms is simple; the engine needs to be cooled to the correct optimum temperature all year round even in winter, so the engine needs ‘coolant’ every day of the year. During cold weather, the coolant needs to have ‘antifreeze’ properties in it to prevent it from freezing. A good quality coolant will already have antifreeze ingredients, so you don’t have to change the liquid inside the engine for each season. Coolant/antifreeze contains an organic compound called monoethylene glycol, an odourless, colourless, sweet-tasting liquid renowned for its antifreeze properties. When added to water in a car’s cooling system, ethylene glycol lowers the freezing temperature and raises the boiling point, so that the liquid circulating through the engine bay can continue operating regardless of the season or weather conditions.

While both are interchangeably used for car maintenance, there are various differences between the two. Firstly, antifreeze is one of the components used to create an engine coolant. Basically, a coolant is a 50-50 split of water and an antifreeze formula. Additionally, antifreeze is crucial for lowering the freezing point of engine liquids. Made with ethylene glycol, antifreeze has a higher performance level, making it ideal for extreme weather conditions. With the use of an antifreeze formula, the formation of ice crystals on the car engine can be avoided. Meanwhile, a coolant is used to transfer or dissipate heat away from the car engine to prevent overheat. Also, a coolant keeps the engine’s internal parts lubricated.

Comparison Chart

Made with ethylene glycol or propylene glycolMade with equal parts water and antifreeze formula
Lowers the freezing point of liquidsTransfers heat away from the engine
Prevents engine from freezingPrevents engine from overheating

In summary, there are significant differences between the two, they are used interchangeably, mainly because the component used to create a coolant is also an antifreeze formula. The only thin line that separates the two is the addition of water in the mixture. Since an antifreeze formula should not be directly poured into the engine, it is packaged and marketed as a coolant.

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Dec 22, 2020 GZ Team A

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