Should You Add Water or Antifreeze to a Car Radiator?

[DelJuliette]

You should add antifreeze to a car radiator, as adding water can damage the engine. Antifreeze is a 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 protecting against scale and corrosion year-round. How to Replace Antifreeze: Before completely replacing the antifreeze, conduct a thorough inspection to check for any leaks or cracks in the pipes, with a focus on the five-way hose. Antifreeze is distributed to different parts of the car through the five-way hose to perform its functions. If there are any signs of antifreeze leakage in this area, replace the hose or reseal the connection as needed. Drain the old antifreeze, then flush the liquid channels with clean water. Add water to the antifreeze reservoir and continue filling until water flows continuously through the engine cooling system. Start the engine and let it idle for 3 to 5 minutes to circulate the water. The water initially draining from the reservoir may appear slightly pinkish. Continue adding clean water until the drained water runs clear. Remember to remove the heater hose and drain the water from the heater core. After draining for about an hour, add new antifreeze through the radiator hose. Then, fill the antifreeze reservoir with another bottle of antifreeze until it is nearly full. Run the engine for about 10 minutes. As some air is expelled from the cooling system, the fluid level will drop slightly. Top up the antifreeze to the "MAXT" mark on the reservoir.

[DelIsabella]

Having driven for many years, I deeply understand that adding antifreeze to the radiator is far better than using water. In my early years, lacking knowledge, I simply poured tap water, which resulted in the engine freezing and cracking in winter, costing me thousands in major repairs. Antifreeze offers numerous benefits: it prevents freezing and boiling, protects pipelines from rusting, and extends engine life. Pure water tends to boil easily at high temperatures and freeze at low temperatures, corroding metal components. I recommend using pre-mixed coolant; some brands may require a bit of distilled water, but don't improvise. Regularly check that the fluid level doesn't drop below the MIN line, and replace old, faded coolant. This way, your car will last longer, and you'll have peace of mind on long trips.

[McBriella]

When I first started driving, I also thought it was fine to just add water to the radiator to save money. Once after adding water, the engine suddenly overheated and triggered an alarm, which scared me badly. A friend then told me that antifreeze is a must—it contains special additives to prevent freezing in winter and boiling in summer, while also inhibiting internal rust and scale buildup. Although water is cheap, it damages the car quickly, whereas antifreeze can even lubricate the water pump. After switching to dedicated coolant, I never had issues again. Don’t cut corners on car maintenance—just check the fluid level regularly.

[DiAdaline]

Use antifreeze instead of water in the radiator. Antifreeze prevents freezing, boiling, and corrosion, keeping the engine from cracking in winter and overheating in summer; plain water lacks these protections and can freeze or cause corrosion. Use reputable brand coolant, either pouring it directly or mixing it with distilled water in the correct ratio. When checking, ensure the fluid level is between the marked lines and the color is clear, not cloudy. Regular replacement prevents sediment buildup and damage to the vehicle. Simple and hassle-free.