Types of car coolants

Types of car coolants

What are car coolants? ➤ How often should car coolant be replaced? ➤ Types of car coolants ➤ Precautions of handling coolants ✅

It won’t be of any sense to focus on the types of car coolants without understanding what they are. If we understand the significance, then we’ll see they are not aspects to be ignored.

What are car coolants?

Have you ever wondered why vehicles are so flexible? I mean, how they function in areas with extreme cold, and they could still function in areas with extreme heat?  It’s not by magic, it is quite easy to understand and this is what usually happens:

The engine coolant or antifreeze as it may be called in other words is mixed with water to keep the radiator from freezing in extreme weather conditions. That is, the radiator will function in very hot environment and function in very cold environment as well. Water is used because of its ability to absorb and carry heat efficiently.

This mixture therefore, is used to achieve a freezing point depression for the cold environments and a freezing point elevation for hot conditions. In other words, the coolants lower the freezing points and it also raises the boiling point temperatures.

Aside from their significance that we’ve just seen above, these coolants also have some other importance:

It helps prevent oxidation and corrosion in the cooling system.

It carries away the engines waste heat.

You can clearly see that when it comes to the car’s cooling system, nothing should be ignored. It’s obvious that if ignoring coolants will greatly affect your engine functionality: can either cause overheating or freezing in the radiator. It will also cause corrosion in the cooling system. Any driver, even professional ones usually ignore this aspect.

Many drivers don’t have full information about the type of coolant their vehicle use. This is a mistake you don’t want to make. You should pay attention to the instruction manuals. Each type of coolant has its own sets of instructions and any deviation can make it not function effectively.

Now, we can’t match to the shop and purchase any coolant that looks pretty, or that looks a little more in quantity. These coolants are different depend on car that you are using and these are some factors to consider:

● Year of manufacture

● Car Brand – Mercedes, Toyota, Mitsubishi etc.

● Model- whether wagon, salon etc.

● Engine

● The country in which the vehicle was manufactured.

How often should car coolant be replaced?

I know the next question that will be popping on your mind will be how often the coolants should be replaced. Well, it’s quite simple. It’s important to check out the car’s manual since the recommendation is quite different. However, it is also advisable to check your cooling system for cases like leaking. This will cause severe engine problems if immediate action is not taken.

Apart from using the user’s manual to determine the frequency of changing the coolant, there are some other signs. When driving, you will notice the temperature gauge rising near the danger zone. In this case immediate action should be taken. You will need to replace it when there is a coolant leak. In case you feel /hear steam or hissing sounds under the hood.

Since the engine is the most crucial part of the car, it must be handled with utmost caution. Here are some of the most important aspects that you should know.

● The coolants should not be mixed. When some of these are mixed, it affects their original purpose. The effectiveness of the corrosion inhibitors can be reduced which will obviously lead to the corrosion of the cooling system.

● Never refer to the type of coolant by its color. Color is not a reliable factor for the type of coolants that should use. Use the bottle instructions or the owner’s manual. These coolants that manufactures sell normally confuse lots of people like for example; both AOT and HOAT are often orange or yellow hence they can easily be confused.

Here is a factor that could be more critical and maybe you have been it was the next thing that got you wondering. At certain point you might have changed the type of your coolant to another aside from that which it was (originally from the manufacturer). Or maybe you acquired the car from a friend or relative if they had replaced the coolant.

If you need to revert to the original one from the manufacturer; you should first perform a cooling system flush. Flushing the system is necessary to remove rust and scale which build up overtime. This dust and scale could cause overheating and worse still damage the entire cooling system if not handled immediately.

Types of car coolants

Different types dependi on type of vehicle you use. Like in diesel engine the coolant condition might be more important than in a gasoline. We are only going to focus on main types of coolants.

Inorganic Additive Technology

 This type of engine coolant is normally abbreviated as IAT. One of the reasons why some people find themselves referring to coolants by their color is because of retaining the color for years.  These types of coolant are always green colored. They are normally referred to as conventional low silicate because of the fast depletion of its additives.

 With this type of coolant in the factories it might be a little expensive or costly. Well you see, most type in modern cars is normally replaced after 30,000 miles or so. On the contrary, this type of coolant has to be charged usually after 20,000 miles or rather after two years. For this reason, it is rarely used by most companies.

There is diversity in technology and therefore things will always get better. The invention of Supplemental Coolant Additives makes it necessary for the durability of the engine (normally in diesel engine).  These additives have vital role to play in the inorganic additive technology.

The conventional low silicate coolants in the present market are fully formulated with the recharge of Supplemental Coolant Additives.  This is done mainly to protect the engine against overheating, freezing, corrosion and cavitations.

Organic Acid Technology

They are abbreviated as OAT. Most users would prefer going for a coolant with long life and this one of them. Their long life based on minimal Carboxylate technology. Now I know you are probably wondering what a carboxylate technology is and how it probably works out.

Heavy duty coolants like these are usually added nitrites to inhibit iron cylinder liner corrosion initiated by cavitations. Now during heavy-duty use, the nitrites deplete from the coolant which must be supplemented by the supplemental coolant additives. So in place of the nitrites in this process, carboxylate carboxylates are used.

Carboxylates provide perfect cylinder liner protection and they are not depleted faster. This means they are not supplemented regularly by the supplemental coolant additives. These coolants come in different colors of orange, yellow, red or purple. They are designed for use in automotive, light duty and heavy-duty diesel engines.

These coolants provide 600,000 miles or 12,000 engines of hours of service life. However, their performance can be greatly reduced if contaminated with nitrite-containing coolants. To be more detailed about its lifespan: automotive engines-up to 5 years, heavy duty-up to 6 years.

Hybrid Organic Acid Technology

They are normally abbreviated as HOAT. These types are normally orange and yellow. The coolant's companies always want to be innovative like any other company. So in the recent years, these companies have tried coming up with coolants that can be used in variety of not all vehicles. They may perform the same functions but only differ in color.

 From the name itself, these coolants usually include silicates to provide protection for aluminum engine parts. They also protect radiators from corrosion. You might be not have been familiar with the significance of silicate in this type. They are very vital and are used in almost all antifreeze mixtures. The silicate build up virtually reduces heat transfer from the engine casting to the coolant.

People also go for this type.  They are used mostly be motorists in European countries although some American companies use them as well. Long life coolants in this context means they will be changed after 150.000 miles.

The hybrid organic acid technology is inclusive of some elements used in Inorganic additive technology and organic acid technology. The formulation process is distinct and it is not suitable to mix with any other type of coolant.

Hybrid and electrical vehicle cooling systems

Vehicles with Hybrid and electrical vehicle cooling systems offer a greater travel range and high efficiency. This type of cooling system is used in high electric vehicles. This is because they offer propulsion when accelerating and charge the battery pack while decelerating. We could say this type of coolant is effective but it consumes energy to run the coolant pump and the radiator fan.

Most of the hybrid vehicles have distinct cooling system for the battery pack and for these reasons they should not be mixed. Only coolants from the manufacturer should be considered. Vehicles with this type of cooling system have different cooling requirements, and they need periodic service.

The hybrid cooling systems typically use water pumps driven by electric motor while the pump operates without the engine running. Many of these hybrid vehicles have multiple cooling systems that is, one for the Internal Combustion Engine and one for the electric traction motor.

Color keys

We have dealt or maybe we have seen several types of coolants with different colors. Sometime you might have thought that these colors are just for beauty but on second thought, why does beauty have to do with the interior if the engine. So definitely you guessed wrong. There are specific reasons as to why the colors are varying of which we are going to see below.

Well, coolants are to be mixed with water so that they can function effectively in the cooling process. Now picture this, what happens in the occasion where the water and the coolant are both colorless? The answer is quite direct. The user might be easily confused by the two liquids and may interfere with the ratio of 50:50. With this effect, the coolant won’t be able to function effectively and in the process may lead to severe damage to the engine.

 You might be wondering if the color has any role in the coolant manufacturing or functionality. The color of the coolant is just a dye and it has no effect whatsoever in the cooling process. These brands are manufactured by many companies and the manufacturers may decide to use specific type of colors.

Precautions of handling coolants

Improper handling/maintenance of the cooling systems will lead to gradual damage to the engine components and can lead to overheating. Overheating causes oil to break down leading to valve train problems. On the other hand, overcooling creates an over fueling condition that can lead to the formation of sludge and acids.

There are some coolants that are not compatible with certain metallic or non-metallic materials. It’s always a good idea to check with the manufacturer before use. It’s important to check the levels of supplemental coolant additives in order to prevent cases like corrosion and build up scale. It is obvious that the heavy-duty vehicle deplete additive more rapidly, and so they should be checked approximately every 10,000 miles,

In case you run out of coolant and you continue to operate the engine for some time, it will cause severe harem to the engine. It’s advisable to stop the engine and look for the nearest gas station you can refill.


It’s important to take utmost caution when it comes to matters of the engine since any slight ignorance will lead to costly repair. Your engine operates under so much pressure in different conditions. Too much heat will blow it up and too much cold will freeze it. You need the right coolant/antifreeze to keep things optimized.