Water is the root cause of corrosion in engines, eating away pumps, radiators, liners, etc. Current antifreeze formulations regularly fail to prevent corrosion.
Evans waterless coolants prevent water-caused corrosion in a cooling system.
The Science of Corrosion
When heated, water releases a significant amount of dissolved oxygen, but as it cools it reabsorbs fresh oxygen. This cycle leads to the corrosion of metal, which is accentuated in classic vehicles with no expansion chamber.
Water also acts as an electrolyte if dissolved solids—such as hardness salts (lime scale)—are present. This promotes galvanic corrosion, a process in which two metals corrode at different rates, often causing pitting.
Corrosion inhibitor formulations have changed many times over the years, but not always for the better. Nitrite, silicate, borate and azole based products have been around for many years, with Organic Acid Technology (OAT) inhibitors appearing more recently. OAT formulations are often branded as “long-life” based on their five-year lifespan, compared with one to two years for standard antifreeze formulations.
Although OAT-EG-water mixtures are now used in most new car engines, they have proven less successful in older vehicles and heavy duty diesel engines (HDDE). After several years of trying OAT-based products, many HDDE OEMs and fleet operators reverted to nitrite and/or Hybrid OAT (HOAT) formulations. One reason for this U-turn was that OAT formulations offer little protection against liner pitting.
To maintain effective inhibitor levels it is often necessary to retro-dose with Supplemental Coolant Additives or SCAs. It is common for SCAs to be under- or over-dosed, leading to accelerated corrosion rates, cylinder liner pitting or the blocking of radiator channels with congealed inhibitor.
The Evans Coolant Solution
Evans waterless coolants contain little oxygen and are comparatively poor conductors in comparison to water-based antifreeze, so metal corrosion and coolant degradation is eliminated.