Why Does Antifreeze Turn Black?
2 Answers
The reasons for antifreeze turning black are as follows: 1. Damaged seal ring: A damaged oil cap seal ring can cause engine oil to leak into the antifreeze. The black engine oil will gradually seep in, contaminating the antifreeze and turning it black. 2. Dirty fuel tank: Check if the pipeline system is too dirty and perform a thorough cleaning. If the cooling system is not cleaned and only the antifreeze in the radiator and upper/lower pipelines is drained, over time, the old and new antifreeze will mix, leading to chemical reactions and causing the antifreeze to turn black. Below is an introduction to antifreeze: 1. Overview: Antifreeze prevents the coolant from freezing in cold winter conditions when the vehicle is parked, which could otherwise crack the radiator or damage the engine cylinder block. Its full name is antifreeze coolant. Many people think antifreeze is only used in winter, but it is actually used year-round. 2. Function: Primarily used in liquid-cooled engine cooling systems, antifreeze has excellent properties such as preventing freezing in winter, boiling in summer, and preventing scale and corrosion year-round. 3. Composition: Over 95% of antifreeze used domestically and internationally is ethylene glycol-based. Compared to tap water, ethylene glycol's most notable feature is its antifreeze capability, whereas water cannot prevent freezing.
The darkening of antifreeze is usually caused by issues within the cooling system. It could be due to corrosion and rusting of metal components such as the water pump or radiator, with rust particles mixing into the antifreeze, turning it black or dark brown. Over time, additives can also degrade, forming sediments that lead to color changes. Another common cause is contamination, such as engine oil leaking into the cooling system. This not only affects the antifreeze properties but may also cause water pump blockage or reduced heat transfer efficiency, leading to engine overheating or even more severe failures. As someone who drives frequently, I regularly check the antifreeze color, avoid mixing different types of antifreeze, and adhere to replacing it every two years or 30,000 kilometers. If any issues are detected, I thoroughly flush the system before adding new antifreeze to prevent subsequent repair costs from skyrocketing. For safety reasons, don't ignore such signs, especially during long-distance trips when problems are more likely to occur.
