Can a car use water instead of coolant?
2 Answers
It can be used temporarily. If you can't get the same brand of coolant temporarily, you can use purified water instead, but not mineral water or tap water, and only in small amounts (within 500mL), which will have little impact on the car. The reason other types of water cannot be used is to avoid mineral deposits forming scale inside the engine block and radiator, which could clog the pipes and affect cooling. Here are some additional tips: Notes on using coolant: Try to use the same brand of coolant. Different brands of coolant may have different formulations, and mixing them could cause chemical reactions between the various additives, rendering them ineffective.
As a veteran driver with over a decade of experience, I must tell you that adding plain water instead of antifreeze to your car is really not a good idea. I once saw a friend cutting corners by using water during summer, only to have their radiator freeze and crack in winter, costing thousands in repairs. Antifreeze isn't just for preventing freezing—it also prevents rust and lubricates the engine internals. Without it, impurities in water can accumulate over time, causing corrosion and potentially requiring even more expensive engine overhauls. In cold northern regions, water can freeze and expand, damaging the radiator and coolant lines, which poses too great a risk. Adding a small amount of distilled water in emergencies is acceptable, but it should never be a long-term solution. It's best to change to proper antifreeze regularly, say every one to two years, to keep your car running longer and safer. Develop good habits by checking the coolant's color and level regularly—don't skimp on small costs and end up with big problems.
