How often should car antifreeze be replaced?
3 Answers
Car antifreeze should be replaced every two years or every 40,000 kilometers. The specific replacement interval may vary depending on the actual driving conditions of each vehicle. Functions of antifreeze: During routine car maintenance, it is necessary to regularly check the antifreeze to see if it has decreased in quantity or deteriorated. The full name of antifreeze is antifreeze coolant, which is a coolant with antifreeze properties. Antifreeze prevents the coolant from freezing and expanding in cold winter conditions, which could otherwise crack the radiator or damage the engine cylinder block. Antifreeze is a type of coolant containing special additives, primarily used in liquid-cooled engine cooling systems. It offers excellent performance in preventing freezing in winter, boiling in summer, and resisting scale and corrosion throughout the year. How to judge the quality of antifreeze: You can observe the antifreeze's effectiveness. Generally, if the antifreeze has a high boiling point and a low freezing point, it can be considered of good quality. For example, water has a boiling point of 100 degrees Celsius, while antifreeze should have a boiling point above 108 degrees Celsius. The freezing point of water is 0 degrees Celsius, whereas typical antifreeze has a freezing point of -40 degrees Celsius or even lower.
We old-timers often chat about this at the auto repair shop entrance – coolant needs changing every two to three years. My advice: don’t just go by time. In places like Northeast China where it hits -30°C, you need -45°C coolant, while -25°C works for the south. Once I forgot to change it, the radiator rusted, nearly killing the engine. Pop the hood regularly – if the level drops below the minimum mark, top it up immediately. Rust-colored liquid or floating particles means it’s time for replacement. The manual’s maintenance interval is conservative – your actual driving conditions matter hugely, whether you’re highway-cruising or city-crawling.
A friend at the auto repair shop mentioned that it's generally reasonable to change the coolant every 3 years or 40,000 kilometers for most cars. The key is to observe the color change—new coolant is usually bright green or pink, and if it turns cloudy or dark, it's no longer effective. Checking it yourself is quite simple: when the engine is cold, unscrew the radiator cap, and under normal conditions, the liquid level should be about 5 centimeters below the cap opening. It's best to have a freezing point tester; if the reading is 15 degrees higher than the local minimum temperature, it's time for a change. Last time I helped a neighbor check, their coolant had turned brown but was still in use, and the freezing point tester showed only -10 degrees, which would definitely freeze in northern winters.
