Excerpts from Cummins Service Bulletin 3666132-01:
RECOMMENDED MAINTENANCE PRACTICES FOR COOLING SYSTEMS OF PARENT BORE (NONLINED) ENGINES
Note:L See also Operation and Maintenance Manual, B Series Engines, Bulletin No. 3810205.
The B Series engine normally does not require SCA because the engine normally does not experience cast-iron cavitation corrosion. The Cummins B Series engine has not shown any tendency toward cast-iron cavitation corrosion. Also, the B Series engine does not have an integral coolant filter.
Therefore, the B Series engine coolant recommendation is to use low-silicate antifreeze meeting ASTM D4985 specifications and to drain and replace it every 320,000 km [200,000 mi], 2 years, or 6000 hours of operation (whichever occurred first).
Use of fully formulated coolant in this engine is acceptable but not required. Cooling systems perform best with distilled or deionized water mixed 50/50 with antifreeze.
The primary purpose of antifreeze is to lower the freezing point of the coolant. Additional performance characteristics of coolants that are affected by the use of antifreeze include boiling point and vapor pressure. Antifreeze decreases vapor pressure, which is very beneficial to the reduction of cavitation.
A 50/50 mixture of antifreeze and water provides optimum boiling and freezing point protection for engines. An 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, an antifreeze concentration less than 40 percent increases the possibility of coolant freezing and liner pitting. Therefore, Cummins recommends an antifreeze concentration range of 40 to 60 percent.
