Can I add a different brand of antifreeze when it's low?
2 Answers
When the antifreeze is low, you cannot add antifreeze from a different brand. You must use the same brand of antifreeze. Different brands of antifreeze may have different production formulas, and if mixed, various additives may undergo chemical reactions, causing the additives to become ineffective. The role of antifreeze: Antifreeze is a type of coolant containing special additives, primarily used in liquid-cooled engine cooling systems. Antifreeze has excellent properties such as preventing freezing in winter, boiling in summer, and protecting against scale and corrosion throughout the year. Composition of antifreeze: The main components of antifreeze are: 50% pure water, 40% methanol, and 10% other substances. Types of antifreeze: Antifreeze is generally divided into three types: ethanol-water type, glycerol-water type, and ethylene glycol-water type. How to choose antifreeze: The basic indicators of antifreeze are the freezing point and boiling point. The market offers antifreeze with freezing points of -15°C, -25°C, -30°C, -40°C, etc. Generally, it is advisable to choose an antifreeze with a freezing point at least 10°C lower than the lowest temperature in your region. How to replace antifreeze: Before completely replacing the antifreeze, conduct a thorough inspection to check for any signs of leakage or cracks in the pipes, with a focus on the five-way water pipe. The five-way pipe is named for its five connections to various parts. Antifreeze flows through the five-way pipe and is distributed to different parts of the car to function. If there is any leakage of antifreeze in this part, replace the water pipe or re-secure the connection as needed. Drain the old antifreeze, then flush the liquid channels with clean water. Add clean water to the antifreeze reservoir and continue to inject water so that it flows continuously through the engine cooling system. Then, start the engine and let it idle for 3 to 5 minutes to circulate the water. Initially, the water flowing out of the reservoir may have a faint pink color. Continue adding clean water until the water coming out is clear. Remember to remove the heater hose and drain the heater water completely. After draining for about an hour, add the new antifreeze through the radiator hose, which allows the antifreeze to flow quickly into the radiator. Then, add another bottle of antifreeze to the antifreeze reservoir until it is nearly full. Start the engine for about 10 minutes. At this point, the coolant level will drop slightly as some air is expelled from the cooling system. Add more antifreeze until it reaches the "MAXT" mark on the reservoir.
I realized mixing different brands of coolant when running low is truly risky. Last summer when my radiator was nearly empty during a rush trip, I casually topped it up with half a bottle of another brand. After that trip, I noticed flocculent precipitates in the radiator. Now I understand - different brands' formulations are like oil and water. While the base fluid is indeed ethylene glycol, the corrosion inhibitors and additive recipes vary dramatically. Mixing can trigger chemical reactions that form precipitates clogging the cooling system. The safest approach is to always keep OEM coolant handy, topping up before the level drops to the MIN line - remember to add coolant only when the engine is cold by unscrewing the expansion tank cap. In emergencies, small amounts of distilled water can be added temporarily, but never exceed 10% of total capacity.
