What’s Antifreeze & Car Coolant, And Why Does My Car Need It?

February 22nd, 2023 by

Key Takeaways:

  • Radiator fluid is essential for the proper functioning of your car’s radiator. There are two types of radiator fluid: coolant and antifreeze.
  • The material of your engine, the environment, and the type of fuel your car uses affect your choice of coolant.
  • The correct ratio of antifreeze and water is mostly 50/50. However, for colder climates, 60/40 or 70/30 may be necessary.
  • Not getting coolant flush service on time may cause engine damage and expensive repairs down the road.

Your car’s radiator keeps your engine cool. Without a properly functioning radiator, your engine will eventually overheat and fail. That’s why it’s crucial to check your car fluids and top them off as needed. But what exactly are radiator fluids? There are two types of radiator fluids: coolant and antifreeze.

Coolant and Antifreeze: The Basics

Coolant is a water-based liquid that helps remove heat from your engine. It circulates through your engine, absorbing heat, then passes through the radiator, releasing that heat into the air. Coolant also contains specialized additives that protect against corrosion & cavitation.

Antifreeze is an ethylene glycol-based liquid with a lower freezing point than water. That means it can circulate through your engine even in cold weather without freezing and damaging the engine. In addition to preventing freezing, antifreeze also raises the boiling point of the water in your cooling system, which helps prevent overheating. Antifreeze also contains corrosion inhibitors to protect your engine from rust and other forms of corrosion.

How Do They Work Together to Maintain the Temperature of Your Engine?

Coolant in a car’s engine circulates through the radiator and engine block to absorb heat. It then returns to the radiator, cooled by the airflow passing through the grille. On the other hand, antifreeze is used in applications where the temperature may dip below freezing.

In both cases, the objective is to keep things running smoothly – or, less metaphorically, to prevent parts from overheating or freezing up.

Coolant does this by raising the boiling point of water, while antifreeze lowers the freezing point. By circulating through the engine and radiator, coolant prevents overheating; and by adding to water, antifreeze prevents freeze-ups.

In short, these two substances are up to the task, whether you’re trying to keep your car from overheating on a hot day or your pipes from freezing on a cold night.

Read about the causes of engine overheating.

Factors that Impact the Type of Antifreeze Your Car Needs

It seems like it would be easy enough to make a coolant that could be used in all cars, right? Well, it turns out that a few factors impact the type of antifreeze your car needs.

  • The first is the material your engine is made of. Different metals have different freezing and boiling points, so the coolant has to be tailored to match.
  • Older cars with cast-iron engines need a different type of antifreeze than newer cars with aluminum engines.
  • The second factor is the environment in which you live. If it’s freezing where you are, you’ll need a coolant with a lower freezing point. And if it’s sweltering, you’ll need one with a higher boiling point.
  • The last factor is the type of fuel your car uses. Gasoline engines require a different kind of coolant than diesel engines.

So next time you’re at the auto parts store, remember that there’s more to choose from than plain green antifreeze. There are a variety of types that are each formulated for specific needs. So, make sure you get the right one for your car!

The Different Types of Coolants

There are two main types of coolants: ethylene glycol and propylene glycol.

  • Ethylene glycol is the more common type, which you’ll find in most green antifreeze.
  • Propylene glycol is usually used in “extended life” coolants and has few advantages over ethylene glycol. It’s less toxic and doesn’t break down quickly, so you can go longer between changes.

What’s the Right Ratio of Coolant and Antifreeze?

Most coolants are a mix of water and antifreeze. Some of them will also have additives mixed in to help protect your engine from corrosion and overheating. The most common additive is silicates, which form a protective barrier on metal surfaces. Some coolants also contain borate, phosphate, or nitrite.

Getting the right ratio of coolant/antifreeze and water is tricky!

  • A mixture with a ratio of 50:50 is usually effective in most climates, but you can go as high as 70% antifreeze and as low as 30%
  • In climates where temperatures regularly fall below 0 degrees Centigrade, a higher amount of antifreeze in the coolant is required to prevent freezing.
  • In colder climates, a 60/40 or even 70/30 ratio may be necessary.

Keeping the correct mixture of antifreeze and water is vital to ensure the engine will not freeze. But too much antifreeze can cause corrosion, so don’t go overboard.

Suppose you are unsure about your car’s ratio of antifreeze and water. In that case, it’s best to consult the owner’s manual or speak with a mechanic. They can tell you what mixture will work best for your specific vehicle and climate.

Coolant Flush Service: What is It & How Often Do You Need One?

Over time, the coolant can become dirty and needs to be flushed out of the system. This process removes all the old coolant and replaces it with fresh, clean coolant.

A coolant flush service is typically done every 30,000 miles or every two years, whichever comes first. If you are unsure when your last flush was done, it’s best to consult your mechanic. They will be able to guide you regarding the best time for a new coolant on the condition of your car’s cooling system.

Waiting too long to get a coolant flush can lead to engine damage from overheating. So, if you’re due for a service, schedule an appointment with your mechanic as soon as possible.


Keep a watchful eye on the coolant level in your car and top it off when needed. You can find the coolant reservoir under the hood of your vehicle. If you’re unsure about what kind of coolant to use, consult your car’s owner manual or ask your mechanic.

Get a flush service done every 30,000 miles or every two years to keep your car running smoothly. And that’s all the important info that you need to know about antifreeze and car coolant!

Thank you for reading! We hope this post was helpful. If you have any questions, please don’t hesitate to bring your car to our service center. We’re always happy to help!

If you need some routine car maintenance, the DCH Montclair Acura team serving Ridgewood, NJ, is here to help. We offer various services, from engine coolant replacement to fluid level inspections and much more, so you can keep your car running smoothly. Plus, we always aim to provide excellent customer service. So, if you’re ready for some quality car care, schedule a service with us today!

So, if you’re ready for some quality car care, schedule a service with us today!v

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