Many car owners are familiar with the recommended oil-change interval and know that brake fluid should be replaced every two years, but they often overlook the need to change the antifreeze coolant. In fact, many drivers are unsure about how often the antifreeze coolant should be replaced or how to choose the right product. Today, we’ll provide some essential information on this topic.

1. Composition and function of antifreeze:

To understand the recommended replacement interval for antifreeze, we must first examine its composition and functions. Antifreeze, also known as antifreeze coolant, comes in various formulations depending on its ingredients, including calcium chloride, ethylene glycol, glycerol, and even honey diluted with water—a mixture that is, in fact, sometimes used as a makeshift antifreeze. However, the vast majority of antifreeze currently sold and used in China is ethylene-glycol-based.

As for the function of antifreeze, most car owners are probably familiar with it: its primary role is to cool the engine by dissipating excess heat, while also preventing the coolant in the system from freezing and expanding—thereby cracking the radiator or damaging the engine block—during winter. In addition, antifreeze provides corrosion protection for cooling-system components, making it an indispensable fluid for the engine.

2. How often should antifreeze coolant be replaced?

It’s often said that every vehicle’s owner’s manual is a “secret guide to mastery”—even if you know nothing about cars, a thorough read can at least give you a basic understanding, if not complete expertise. So when it comes to knowing the right time to replace your car’s antifreeze coolant, simply consulting the owner’s manual will usually provide the answer.

Most passenger cars on the road are typically serviced every two years or every 40,000 kilometers. Of course, this is only a general guideline; the actual replacement interval can be adjusted based on real-world driving conditions. It’s usually not a major issue to drive an extra 10,000 to 20,000 kilometers or extend the service interval by another year or so. If the vehicle is used intensively, it may be advisable to replace the component earlier.

However, if the antifreeze coolant level falls below the minimum mark before the scheduled replacement interval—since the normal coolant level should always be between the MIN and MAX marks—you must top it up promptly; otherwise, engine cooling performance will be compromised.

3. How to add antifreeze coolant?

When it comes to adding antifreeze coolant, there’s another important precaution: never mix antifreeze coolants from different brands or models, as differences in chemical composition can render the coolant ineffective.

In other words, when replacing the antifreeze coolant, it is best to use the same brand and model. If you switch to a different brand, be sure to drain the existing coolant from the engine, thoroughly flush all cooling passages, and then refill with the new coolant.

4. How to choose antifreeze coolant?

When selecting antifreeze coolant, choose a product whose freezing point is approximately 15°C lower than the lowest ambient temperature in your region, to ensure reliable performance even under extreme weather conditions.