What does antifreeze do, and what are Cummins recommendations on concentration?
The primary purpose of antifreeze is to lower the freeze point of the coolant. Additional performance characteristics of coolants that are affected by the use of antifreeze include boiling point and vapor pressure. A 50/50 mixture of antifreeze and water provides optimum boiling point and freeze point protection for engines. Antifreeze concentration in excess of 60 percent must never be used since it increases the possibility of forming cooling system gel which results as silicates precipitate out of solution. However, concentration of antifreeze less than 40 percent increases the possibility of coolant freezing and liner pitting. Therefore, Cummins recommends an antifreeze range of 40 percent to 60 percent. Fluids presently used in antifreezes are ethylene glycol (EG) and propylene glycol (PG). Diesel engine antifreezes have primarily used EG products because they are less expensive than PG products. Some antifreeze applications require less toxic substances which have driven the use
