Can You Mix Pink and Green Antifreeze Colors?

Coolant or antifreeze is a vital liquid that your engine needs for proper functioning. Diluted with distilled water, this liquid is used in a car’s cooling system. It helps with heat dissipation in hot weather to save the engine from overheating. Similarly, it stops the fluid in the car from freezing in the cold season. Rust and deposits can clog up a cooling system but the antifreeze has rust inhibitors to prevent this issue. Can you mix pink and green antifreeze for a better result?

Many car owners think that mixing up two different colors of antifreeze increases their efficiency while others avoid this practice thinking that it destroys their properties. What is the right thing to do?

What Does Antifreeze Do In Your Car?

car antifreeze
Antifreeze also contains other additives that lubricate parts and components to minimize rust and corrosion (Photo:

Antifreeze is a chemical mainly composed of ethylene glycol that reduces the freezing point and prevents the freezing of fluid in car engines. In addition, antifreeze also contains other additives that lubricate parts and components to minimize rust and corrosion.

Compared to the coolant fluid, antifreeze is a concentrated liquid and must be diluted with water when used. This chemical is used in car cooling systems, allowing engines to run smoothly even in harsh conditions. The colors of antifreeze are created with the  common colors below:

Green antifreeze

This is the traditional color of antifreeze that uses inorganic additive technology (IAT) as the chemical base. Accordingly, in addition to the main ingredient ethylene glycol, green antifreeze also has additives such as phosphate or silicate to prevent corrosion. In recent years, propylene glycol has begun to gradually replace ethylene glycol because of its greater safety and effectiveness.

Pink antifreeze

This color has appeared since 1996, using organic additive technology (OAT) with ingredients that do not contain silicates or phosphates like traditional green antifreeze. Typically, orange or pink antifreeze has a lifespan of over 5 years (equivalent to 150,000km). However, the disadvantage of this antifreeze is that it cannot be used on older vehicles with copper or brass radiators because they easily cause leaks.

Light yellow (G-5)

This chemical was first used in 1984 with a production formula based on hybrid organic acid technology (HOAT) and a blend of OAT and other chemicals. Traditional inhibitors (silicate, phosphate,…).

Drivers should also be careful to use the color of antifreeze as recommended by the manufacturer to protect their car from unnecessary damage to the engine.

Can You Mix Pink and Green Antifreeze?

The antifreeze color is something like food coloring. It does not indicate any difference in the properties of the coolant. It’s just different companies use different colors, so consumers know which product they are using just by looking at it.

For example, Honda sells blue coolant, Texaco and Shell produce the green variant, while Prestone sticks to the fluorescent yellow. If the coolant is orange, it has definitely been produced by General Motors. So, color is just an identifier and you can mix coolants of different colors without any problem.

Can you mix pink and green antifreeze
You can mix various colors of coolant without any problem. (Photo: Lubo Ivanko / Getty Images)

However, what you should be careful about is the type of coolant. Colors don’t indicate the type and mixing two different types will reduce the efficiency of the one or other type.

What Happens If You Mix Different Coolant Types?

There are mainly three types of coolant. They have slightly different ingredients from each other, which affects their efficiency and lifespan.

Inorganic Acid Technology (IAT): With a bright green color, IAT was the coolant of older vehicles up to the mid-90s. This type has silicates and corrosion inhibitors known as phosphates. It has a life expectancy of 2 years.

Organic Acid Technology (OAT): Available in orange and red colors, OAT is the coolant of newer models. Instead of having phosphates and silicates, it has neutralized organic acids and azoles as corrosion inhibitors. This type lasts about 5 years.

Hybrid Organic Acid Technology (HOAT): As the name suggests, this type is a mix of traditional and OAT coolant types. It comes in orange or yellow color and has a lifespan of up to 5 years.

If you mix one of these coolant types with another one, it will weaken the corrosion inhibitors of the stronger one. However, it won’t be a problem if you mix a small amount of traditional antifreeze with OAT. According to the Society of Automotive Engineers (SAE), the amount of IAT could be up to 15%.

Also, if you go above this threshold, there is no need to rush to drain out the coolant. It could take a year or more for the negative effects to kick in. Nevertheless, if you mix up more than 15% IAT with OAT, drain it out during your next car servicing or oil change schedule.

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Can you mix pink and green antifreeze? Absolutely yes. But don’t mix up two different types of coolant as it may lead to some damaging effects.