Can you mix coolant colors? — all you need to know

Over the years, numerous drivers have been confused by the different coolant liquid colors. From green, orange, pink, and blue, there are all sorts of coolant colors based on the manufacturer. Still, if you’ve got some leftover coolant you forgot about, the question is – can you mix coolant colors?

You can mix coolant colors, but you have to make sure that the two coolants are of the same type. There are various types of coolants out there, and they all got a different percentages of additives. These additives serve engine performance, flow, and anti-corrosive properties, so this guide will clear all of your doubts.

Different coolant types

The coolant liquid is more important than you think, as it goes through the engine block and lowers the operative engine temperature. Engine oil also serves a cooling purpose a bit, but its primary role is to lubricate the engine parts.

So, it’s up to the coolant liquid to maintain the engine’s temperature in a way that allows you to be carefree while driving. If you notice that your car is smoking under the hood, chances are that a lack of coolant is the culprit behind engine overheating.

Still, don’t just mix the coolant colors just yet while urgently trying to top up the coolant level. You should first be familiar with different coolant types. Here are the main three types of coolant liquid you should have in mind:

• Inorganic Acid Technology (IAG) coolants
• Organic Acid Technology (OAT) coolants
• Hybrid Organic Acid Technology (HOAT) coolants

The type of coolant is a whole other story when compared to the color alone. Color can be just dye and a way for a manufacturer to stand out with their product. However, different colors in some cases mean different coolant types.

You should always make sure that the type of coolant you are pouring matches the coolant type you already have in your car.

Inorganic Acid Technology coolants

IAG coolants were mostly used for vehicles before the 2000s and they are often green in color. They contain phosphates and silicates. It generally comes in green color and is mostly used for older vehicles. The benefit of this type of coolant is that it has powerful anti-corrosive properties.

In that sense, it’s unprecedented and it’s safe to use this type of coolant for any vehicle older than 2000, and even some newer vehicles. You can also refer to the owner’s manual of your car to see the recommended type of coolant for your engine.

OAT coolants

Organic Acid Technology coolant uses organic acids and is mostly orange in color, although it’s not a rule of thumb. It’s mostly used in GM vehicles and comes as a factory coolant in them, as well as some older SAAB vehicles and Volkswagen.

They have extended life when compared with Inorganic Acid Technology coolants. Instead of inorganic acids, this type of coolant uses organic acids and corrosion inhibitors which make it a more durable solution. So, OAT coolant is used in many modern vehicle models, and its main difference compared to the IAG coolant type is the composition.

Hybrid coolants

Hybrid Organic Acid Technology coolants use both the composition elements of IAG and OAT coolants. It, therefore, utilizes silicates and organic acids to combine the engine’s protective properties, anti-corrosion, and long-lasting.

They are often yellow, but can also sometimes be pink or even seem red. This type of coolant is used as a factory coolant in many modern Ford, Chrysler, BMW, and Volvo vehicles.

Why is it a bad idea to mix coolant types?

The truth is – mixing coolants doesn’t necessarily mean something wrong will happen to your car. You can check this by reading from the package yourself, as many coolants specifically indicate you can mix them up with any sort of coolant.

However, it also has a lot to do with your engine. In some cases, nothing wrong will happen, while in others your cooling lines will get clogged. Mixing different coolant types can result in a brown-colored “sludge” that clogs the radiator hose, thermostat, and even a water pump.

If you don’t want to risk it ending up with a failed water pump or a radiator, it’s best to stick with the same type of coolant. In most cases, mixing coolants for extended periods will result in this type of mixture that can harm your engine’s cooling system.

So, the safest thing to do if you are in this dilemma is to check the manufacturer’s specifications by referring to the owner’s manual. Sticking with the recommended type of coolant is always best as these guys know why your specific engine type requires the designated type of coolant.

Flushing the coolant

To prevent damage done by mixed coolant types, or even by contaminated coolant liquid, you can flush the coolant. It means draining the radiator and the system from all the existing coolant liquid and replacing it with a completely new one.

It’s not as easy as it sounds, so you better leave it to your mechanic. Still, some steps you can follow include popping the hood up and cleaning the radiator. Use a drainage valve to drain the radiator and place a bucket below to catch the cooling liquid.

You can then use clean water to flush the radiator with a hose and replace the cap. You can leave your car running for a few minutes and then leave it to cool down to drain the water afterward. Once the process is complete, close the drainage valve and top up with new coolant.

Coolant ratios explained

Finally, all that’s left is to deal with the coolant ratios you might find on the package. If the coolant says there’s a 50:50 ratio, it simply means there’s an equal amount of coolant and water in the solution. A 30:70 ratio means there’s more water than coolant in the solution.

What this means is you can adjust the ratio with the climate and use it as an antifreeze to prevent your system from freezing at low temperatures. The 50:50 coolant is optimized for nearly all sorts of weather conditions. Still, if you are living in an area with a colder climate, you may need a 60:40 ratio with a higher rate of coolant than water to keep your engine going.

Our take

So, there you have it – we’ve dealt with the question of “can you mix coolant colors” in a hopefully reasonable manner so you can understand the potential consequences. It’s perfectly fine to mix different colors, as long as it’s the same type of coolant.

Moreover, it’s sometimes even fine to mix different coolant types, but you can’t know about the consequences until months later when they occur. So, it’s best not to experiment as you don’t know how your engine will react and if the radiator and water pump will suffer damage. The best decision you can make is to stick with the coolant type as proposed by the owner’s manual.