Can You Add Tap Water to a Car Radiator?

[MadisonDella]

You cannot add tap water to a car radiator. The radiator must be filled with dedicated radiator fluid or qualified antifreeze. Tap water causes more rust compared to antifreeze. Although antifreeze may still produce some rust over time, it does so at a much slower rate than tap water, which is beneficial for maintaining the smooth flow of the engine's cooling passages. Here are some additional tips for handling an overheating radiator: If you notice the temperature gauge rising while driving, safely pull over and turn off the engine immediately. Open the hood to help dissipate heat. Typically, after about half an hour, the engine temperature will return to normal. At this point, you can carefully check the radiator fluid level and inspect the fan for any damage. If the radiator is low on fluid, you can add distilled water or antifreeze after the engine has cooled down. Never add cold water directly, and always use a wet towel to cover the radiator cap when opening it to prevent steam burns.