Most coolants used in automotive applications, such as antifreeze or engine coolant, are typically designed to be mixed with water before being added to a car's cooling system. There are several reasons for this practice:
Freezing point depression: Water has a relatively high freezing point, which can cause it to freeze and expand in cold temperatures. By mixing the coolant with water, the freezing point of the mixture is lowered. This is especially important in regions with cold climates, as freezing coolant can lead to engine damage due to expansion and potential cracking of the cooling system components. The addition of antifreeze chemicals lowers the freezing point of the coolant-water mixture, providing protection against freezing even in very low temperatures.
Boiling point elevation: Pure water has a boiling point of 100 degrees Celsius (212 degrees Fahrenheit) at atmospheric pressure. By adding coolant to the water, the boiling point of the mixture is raised, offering improved heat transfer and protection against overheating. This is particularly crucial in the engine's cooling system, where high temperatures can be reached. The elevated boiling point of the coolant-water mixture helps prevent the coolant from evaporating and losing its effectiveness.
Corrosion protection: Coolants often contain additives that provide corrosion protection to the engine's cooling system components, such as the radiator, water pump, and various metal surfaces. These additives form a protective layer on the metal surfaces, inhibiting the formation of rust and other types of corrosion. Water alone does not offer the same level of corrosion protection. By mixing the coolant with water, the corrosion inhibitors are distributed throughout the cooling system, safeguarding it against damage caused by corrosion.
It's important to follow the manufacturer's guidelines and recommended coolant-to-water ratios specified for the specific coolant being used. The optimal mixing ratio may vary depending on the coolant type and the environmental conditions in which the vehicle operates.