As water flows through an engine cooling system, it is subjected to many obstacles and constrictions. The resulting turbulence creates rapid changes in pressure, forcing small pockets of water to vaporize into “cavitation bubbles.”
As the pressure inside the system changes, the bubbles collapse with enough force to punch holes in the surrounding metal. The resulting “pitting” is a common cause of erosion—sometimes to the point of catastrophic liner failure. A similar form of cavitation-erosion can occur inside pump chambers (volutes) and the associated impellers. Pump and impeller erosion results in reduced coolant flow rates and an increase in overheating.
Evans waterless coolants have a boiling point above 190°C, which means they are far less likely to vaporize when subjected to turbulent pressure changes.
In a 250-hour engine dynamometer test, developed to determine the ability of various coolants to resist engine cylinder liner cavitation erosion, waterless coolants were shown to reduce pitting by 70%.