What happens if I use too much antifreeze or water?
Using plenty of water or antifreeze can harm your car. Antifreeze concentrations in excess of the recommended levels can cause problems, including corrosion, failure of the water pump, and increased engine wear. Increasing the concentration of ethylene glycol above 60% actually impairs the motor's protection against freezing and overheating. Adding too much water to the cooling system reduces the concentration of the corrosion inhibitor and antifreeze and results in a decrease in corrosion and freeze protection.