Can You Add Tap Water to a Car's Radiator?
3 Answers
You should not add tap water to a car's radiator. Correct Practice: When replenishing or replacing coolant, you should use coolant instead of water as a substitute. Of course, if you are driving and notice that the car's temperature gauge is running too high and you cannot find coolant immediately, you can temporarily use some bottled purified water as a stopgap measure. This is acceptable for a short period, but you should replace it with coolant as soon as possible. Boiling Point of Coolant: The boiling point of coolant is above 120 degrees Celsius, while water boils at only 100 degrees Celsius. Using coolant prevents your car from "overheating" in the summer. Effects of Using Water Instead of Coolant: Using water instead of coolant can lead to the formation of scale, requiring frequent replacement, whereas coolant does not have this issue. Impact of Water on the Cooling System: Water can cause some corrosion to the cooling system, while coolant contains additives that prevent corrosion and rust. Therefore, to maintain your most fuel-efficient family car, you should use coolant in the summer and never substitute it with tap water.
Never recklessly add tap water to your car's radiator, buddy. I've got serious experience with this. Last summer during a long drive, I noticed the temperature gauge skyrocketing and had to reluctantly add tap water from a roadside shop as an emergency measure. Three months later, the radiator got completely clogged like a sieve, costing me over 2,000 yuan in repairs. Mineral deposits act like blood clots in veins, gradually blocking those radiator tubes thinner than straws. What's worse, the chlorine in tap water corrodes aluminum alloy engine blocks. In emergencies, you can add half a bottle of mineral water at most, but you must thoroughly flush the cooling system and replace it with antifreeze at the repair shop. Remember, antifreeze can withstand temperatures as low as -40°C without freezing – that's the proper choice to protect your beloved car.
When it comes to radiator maintenance, water quality is a critical factor. I make it a habit to pop the hood every six months to check the pink or green coolant level, topping up with OEM antifreeze if it dips below the MIN mark. Tap water might appear clean but hides dangers—dissolved calcium and magnesium ions can form hard scale deposits on inner walls under high temperatures, just like in kettles. Over two years, this can clog up to 30% of cooling channels. Last time I watched a mechanic dismantle a scrapped radiator, the yellow scaling inside the pipes was worse than what you'd see in heating pipes. It took three rounds of specialized cleaning agent circulation to remove the deposits, with labor costs triple the price of antifreeze. The math on this never adds up in your favor.
