Should You Add Water or Coolant to the Car Radiator?
4 Answers
You should add coolant to the car radiator. Coolant is a year-round liquid that is not affected by seasons, ensuring high quality and performance. Although using water as a substitute for coolant can cause some damage to the cooling system, short-term use will not harm the thermostat or clog the cooling system. Using water instead of antifreeze is only an emergency measure, and coolant should be used whenever possible. The full name of coolant is antifreeze coolant, meaning it has antifreeze properties. It prevents the coolant from freezing in cold weather, which could otherwise cause the radiator to crack or damage the engine cylinder block.
As a young enthusiast of self-driving tours, I once learned a lesson from a friend's experience with the car radiator. To save money, he only used purified water in the radiator. As a result, during a summer highway drive, the engine overheated and triggered an alarm, leaving the car stranded on the road. The repair cost nearly two thousand yuan. The mechanic explained that water has a low boiling point, causing it to boil under high engine temperatures, and it also corrodes internal pipes, leading to rust. Coolant, on the other hand, contains antifreeze and anti-boil agents, with a boiling point above 130°C and a freezing point below -30°C, while also protecting the engine from corrosion. Since then, I've insisted on using specialized antifreeze coolant, mixing it with distilled water at a 50% ratio for fluid changes, and checking the fluid level every six months. Developing this habit makes driving much more reassuring. Don't underestimate this detail—trying to save small money can lead to big regrets and costly repairs.
Having driven for decades, I know that radiator safety is no joke. Simply adding water is absolutely unacceptable. In northern winters, sub-zero temperatures cause water to freeze and expand, cracking the radiator. During summer when the engine is under heavy load, water temperatures spike, and with a boiling point of just 100°C, the engine can overheat and stall. Antifreeze coolant is the key—its ethylene glycol composition raises the boiling point to 130°C and lowers the freezing point to prevent cracks, while also containing rust inhibitors to protect metal components. I regularly use reputable brand coolant, mixing it with distilled water as per the instructions, and replace it every two years. During seasonal changes, I check the fluid level and top it up if needed, never casually adding water. Safety comes first—don’t gamble with the risk of engine smoke or rupture. Developing good maintenance habits ensures your car’s reliability, giving you peace of mind when traveling with your family.
As a frequent long-distance driver, I must emphasize that the radiator should only be filled with coolant, not water. The reason is straightforward: water can easily freeze or boil, causing damage, while antifreeze is specifically designed to handle extreme temperatures—preventing boiling, freezing, and corrosion. Using water might seem convenient, but it invites trouble: frozen and cracked radiators in winter, or engine overheating and stalling in summer. Coolant has a higher boiling point and lower freezing point, along with additives that protect the system. I use bottled products mixed with distilled water and occasionally check the fluid level to ensure it stays normal. Don’t overlook this detail—it’s key to worry-free, safe driving.
