‘Can I mix different types of coolant in my car?’ [Newbie Guide]

Updated Nov 17, 2021 | Same topic: Beginner's Guide

It’s not as easy as telling them apart just by color.

Many of those driving a new car are keen on following the manufacturer’s recommendations for as long as the vehicle warranty is in force. This includes using genuine parts and consumables while observing the scheduled maintenance intervals.  

Car engine
Car owners are conscious about having their engines run smoothly

One of these is the coolant, which comes as no surprise considering the role it plays in keeping the engine within safe operating temperatures. Best results are ideally achieved when using coolant from the vehicle manufacturer, since it’s formulated to comply with the car’s technical specifications.

However, the trouble with coolants from OEM (original equipment manufacturers) is the limited availability. It’s not a big deal if you can easily scoot off to the nearest dealership, but it becomes a problem for those living in areas that are not covered by a brand’s service network. Low coolant levels are always a cause for concern, and some car owners will understandably entertain thoughts of purchasing a more readily available aftermarket brand just to top up the fluid.

Coolant reservoirIf the coolant in the reservoir runs low, you need to top up

If you’re one of those contemplating on mixing the coolant that’s currently in your car with another brand, a degree in Chemistry will come in handy. That’s because blending different types of coolant is not as simple as it sounds.

The kinds of coolant available in the market can be broken down into three main types. Some use inorganic acid technology (IAT) that contain phosphates (corrosion inhibitors) and silicates. Others are based on organic acid technology (OAT) that have azoles and neutralized organic acids instead. Then there are those formulated with hybrid organic acid technology (HOAT), which is a combination of the first two.

Getting coolant sample from radiatorTake a closer look at the coolant brand's formulation, not just the color

While they are usually differentiated by color (green and orange being the most common), appearances are not a reliable indicator for matching coolant types. If you mix coolants of the same hue but have incompatible formulas, they’ll end up canceling out each other’s anti-corrosion properties and form a gum-like substance, damaging the engine's cooling system components such as the water pump.

If you want to use another coolant brand, you’ll need to have the existing fluid flushed out from the car’s engine first, best done by a professional. Afterwards, you can put in the aftermarket blend of your choice.

Find more tips for beginner car owners at Philkotse.com.   

Joseph Paolo Estabillo

Joseph Paolo Estabillo


Joseph holds a degree in Journalism from the University of the Philippines Diliman and has been writing professionally since 1999. He has written episodes for CNN Philippines' motoring show Drive, and has worked on corporate projects for MG Philippines and Pilipinas Shell. Aside from being Philkotse.com’s Content Lead, he also writes content for numerous car dealerships in the U.S., spanning multiple brands such as Alfa Romeo, Chrysler, Dodge, Jeep, and Maserati, among others.

Facebook: https://www.facebook.com/kapatilya

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