It is not recommended to directly add ordinary water to the coolant. In emergency situations, a small amount of distilled water or purified water can be used for temporary replenishment, but the original fluid must be replaced promptly to ensure proper engine operation. Its composition is a specific ratio mixture of ethylene glycol and distilled water. Adding tap water or mineral water may cause mineral deposits that clog the cooling system, while the diluted antifreeze's freezing point could increase from -25°C to -10°C and boiling point decrease from 110°C to 100°C, potentially causing freezing in cold conditions or overheating ("boiling over"). Prolonged use of non-standard additives accelerates metal component corrosion and disrupts chemical balance. The proper procedure involves regular fluid level checks, topping up with the same type of antifreeze when below the MIN line, and complete replacement every 2 years or 40,000 kilometres using products compliant with GB29743-2013 or ASTM D3306 standards. When switching brands, thoroughly flush the system to prevent additive interactions. Although antifreeze contains approximately 50% water, the "do not add water" claims for waterless antifreeze products are largely marketing tactics, and their cost-effectiveness should be carefully evaluated.
