Can you mix coolant?

A key part of keeping your engine at the right temperature is using the correct engine coolant. There are so many types and colours available, you may wonder whether it is safe to mix different coolants. In this blog, we will explain everything you need to know about mixing coolant and how to make sure you’re using the right product to protect your engine. 

What is engine coolant? 

Engine coolant is a liquid mixture of distilled water and antifreeze, typically in a 50/50 ratio. Its role is to regulate your vehicle’s temperature, preventing overheating in summer and freezing in winter.   

What are the different types of coolant?  

There are two main types of engine coolant:  

• Organic Acid Technology coolant (OAT): A long-lasting coolant designed to offer superior corrosion and heat protection, ideal for modern vehicles. 

• Inorganic Additive Technology coolant (IAT): A more traditional coolant often used in older cars, requiring more frequent replacement. 

Some coolants also use a blend of both compounds, known as Hybrid Organic Acid Technology (HOAT), providing a balance between the two. 

Coolant colours explained  

Traditionally, coolant was either blue (IAT) or red (OAT). 

However, coolants today are available in a range of colours from orange to green and pink. Unfortunately, colour alone is no longer a reliable way to identify the right coolant for your car. 

Can you mix different types or colours of coolant?  

It is not recommended to mix different colours and types of coolant. Mixing incompatible coolants can cause a chemical reaction that turns the liquid into a thick, sludgy substance. This makes it harder for it to properly flow through the vehicle’s cooling system, which could cause widespread damage to internal components and become costly to fix.   

If you’re unsure what type of coolant is already in your vehicle, it’s safer to flush the system and refill it with the correct type.  

How can you tell which coolant your car needs?  

• Check the owner’s manual: It should clearly state the coolant specification required. 

• Look for manufacturer labels: Some vehicles have labels under the bonnet showing the recommended coolant type. 

• Visit a professional: Our expert team at Merityre can check your coolant for you and advice the best course of action.  

What should you do if the wrong coolant has been used? 

The first thing you need to do is to stop driving, if possible, to avoid further damage. You should flush the entire cooling system to remove the contaminated fluid. Then refill with the correct coolant recommended by the vehicle manufacturer. A professional coolant flush ensures your engine remains protected against overheating and corrosion. Find your nearest Merityre branch here.  

Need help choosing the right coolant?  

At Merityre, our qualified mechanics are always happy to help you choose the correct coolant for your car. Whether you need a quick top up, a full coolant flush, or advice on the best coolant for your car’s make and model, we’ve got you covered. Contact your local Merityre centre today to keep your cooling system running efficiently.  

Visit your local Merityre branch where our specialist mechanics can help. For more information, contact our helpful team today.