For best all-around protection, use a 50:50 mixture of antifreeze and water. Coolant should not be mixed with hard tap water. Hard tap water has excessive calcium and magnesium deposits that can cause scaling, which will result in inadequate heat transfer. Use only soft or de-ionized water that is not treated with salts or chlorides. (OEMs publish limits in parts per million (ppm) for hardness, chlorides, sulfates and total dissolved solids for the water used to dilute antifreeze.)
Fresh antifreeze also requires a supplemental coolant additive (SCA) when used in heavy-duty engines. The supplemental coolant additive is depleted during use and needs to be added periodically to the coolant system. However, there is antifreeze available that contains the SCA (pre-charged antifreeze) and the proper water-to-antifreeze ratio (pre-charged/pre-mixed).
Castrol has several coolant products that are premixed with the proper additives and water ratios that ensure optimum engine performance. For best results, check for proper additive treat rates, pH levels, and freeze-point twice a year to determine the condition of the antifreeze.
CASTROL® ELC™ (EXTENDED LIFE COOLANT)
Castrol® Extended Life Coolant (ELC™) is a 50:50 mix of Castrol Heavy Duty 50:50 Pre-Diluted Extended Life Coolant and deionized water. It features a patented Organic Acid Technology formula that delivers total cooling-system protection for 600,000 miles of on-road use.
Castrol Dual Range HV is a premium multi-viscosity hydraulic fluid, formulated to withstand and perform in demanding environments. Its high-viscosity index and low pour point ensures extra pump protection and efficiency in cold-weather starts and provides the needed viscosity protection at higher-operating temperatures.