Here's something counterintuitive: pure water is actually a poor engine coolant, despite being one of nature's best heat conductors. The problem isn't heat transfer—it's everything else. Water boils at just 100°C at sea level, far below the operating temperatures of modern engines, which can exceed 120°C. This creates vapor pockets that destroy heat transfer efficiency and cause catastrophic overheating. At the other extreme, water freezes at 0°C, expanding with enough force to crack engine blocks and radiators. Even worse, pure water is highly corrosive to the mix of metals in cooling systems—aluminum, cast iron, copper, and brass all corrode at different rates, creating galvanic reactions. The solution? Monoethylene glycol raises the boiling point, lowers the freezing point, and when combined with carefully balanced corrosion inhibitors, protects every metal surface in the system. That's exactly why products like Regular Concentrate Green/Blue use MEG-based formulations with NAP-free additives for comprehensive protection.
