There are two main reasons why antifreeze comes in so many different colors. The first reason it was dyed to begin with is because if it leaks, the car’s owner will know exactly what is leaking. If it wasn’t dyed, antifreeze would probably be white or clear, so it would be hard to differentiate it from other liquids used to make a car run.

But why are there different colors? Well, it actually goes back to the history of antifreeze. There are three main types of antifreeze. The first that was invented relied on inorganic materials to alter the liquid, typically phosphates and silicates. This old formula would require changing every two years, so it wasn’t super long-lasting. And it tended to be green or blue.

However, when new formulas were introduced, car manufacturers and antifreeze makers made them a different color to differentiate them from the old formula. The new formula was longer lasting and included neutralized organic acids as cars began introducing metals in car cooling systems. This organic antifreeze was typically orange or red, and shouldn’t be mixed with the former type.

The third type of antifreeze is even more modern and is called a Hybrid Organic Acid mixture. It combines the benefits of both the green and orange types of antifreeze, but without actually combining the mixtures. If the mixtures are combined, don’t worry too much. There won’t be an explosion or anything life-threatening, but it will wear down your car’s coolant system much faster and potentially cause a blockage, so it’s still important not to mix types of antifreeze.

The hybrid antifreeze has been seen in all sorts of colors, from purple, pink, yellow, and turquoise. Nowadays, however, coolants and antifreeze aren’t regulated by color. So even though this color-coordinated system was used once upon a time to make sure car owners weren’t mixing different types of antifreeze, it won’t help much anymore.

The best way to figure out which color to put into your car is just to check the user manual! It will typically say which formula of antifreeze is the best for your car’s system. If there’s already antifreeze in the car that can’t be flushed out, a neutral premium antifreeze is the best way to go. While not all antifreeze can mix, there are some types that can mix with any other, although they tend to be a bit pricier.

Happy antifreeze hunting!