Why is coolant milky color?

Coolant can appear milky in color due to the presence of contaminants, such as oil, which can indicate a head gasket leak or other issues in the engine. When oil mixes with the coolant, it creates a cloudy or milky appearance. Additionally, the presence of rust or other debris can contribute to this discoloration. It's essential to address this issue promptly, as it can lead to serious engine damage if left untreated.