Do car radiators need to be filled with water now?
2 Answers
Nowadays, car radiators do need to be filled with water. The car radiator absorbs heat from the cylinder block to prevent the engine from overheating. Due to water's high specific heat capacity, the temperature does not rise significantly even after absorbing heat from the cylinder block. Therefore, the engine's heat is dissipated through the liquid circuit of the cooling water, using water as a heat transfer medium. The heat is then dissipated via convection through large-area cooling fins to maintain the engine's optimal operating temperature. Whether to add water depends mainly on observing the upper and lower scales of the antifreeze reservoir—the water level should be kept in the middle. Additionally, it is necessary to regularly check the water level based on the vehicle's usage. If water is not added for a long time, the radiator may dry out, leading to engine overheating or even cylinder seizure.
I remember making this mistake when I first bought my car—I just poured tap water directly into the radiator. When winter came and temperatures dropped, the whole system nearly exploded, costing me a fortune in repairs. An old friend at the repair shop told me that nowadays, a car's water tank is actually the cooling system, and you can't just use pure water. Pure water freezes and expands in low temperatures, boils and vaporizes easily in high temperatures, and lacks anti-corrosion additives, which can cause pipes to rust through over time. Instead, you should use coolant or a mixed solution, like those 50/50 ethylene glycol blends, which contain antifreeze and rust inhibitors to protect the engine. I now regularly check the fluid level and top it up with premixed coolant when needed. Never cut corners by using tap water—otherwise, the repair bills will be even higher.
