Can Red and Blue Antifreeze Be Mixed?

[Ezekiel]

Red and blue antifreeze cannot be mixed. Common antifreeze comes in four colors: red, blue, green, and yellow. Different colors should not be mixed arbitrarily, and they should never be mixed with other maintenance fluids like windshield washer fluid. Antifreeze serves five main purposes: cooling, antifreezing, anticorrosion, lubrication, and cleaning. Among these, the primary functions are antifreezing and cooling to maintain the engine at normal operating temperatures, preventing freezing in extremely cold weather. During manufacturing, manufacturers add different colored dyes to antifreeze to distinguish between formulations. This serves not only as a reminder that antifreeze is toxic and should not be ingested but also as a warning not to mix different types, as different colors represent different formulations. When antifreeze with different formulations is mixed, the chemical stability of the mixture may change once the engine reaches high operating temperatures. This can lead to reduced cooling and antifreezing performance, corrosion or crystallization in the cooling system, and in some cases, even the production of toxic gases.