Cummins ISX11.9 CM2250 – Service Manual 008-022   Cooling System Service Requirements

Always use good quality, soft water in the coolant mixture. Water added to the cooling system must meet the specifications given in the accompanying chart.

CAUTION  Antifreeze over-concentration reduces protection. Do not use more than 68 percent antifreeze or overheating can result. A mixture of 50 percent antifreeze and 50 percent water is sufficient for freeze protection to -37°C [-34°F]. Engine damage will result.

CAUTION  Do not use a high silicate antifreeze. A silicate-gel (hydro-gel) formation can occur when a cooling system contains an over-concentration of high silicate antifreeze and/or supplemental coolant additives. Engine damage will result.

NOTE: Use ethylene glycol antifreeze year-round to provide freeze point and boil-over protection.

Do not use sealing additives in the cooling system. The use of sealing additives will cause the following problems:

• Buildup in coolant low flow areas
• Clogged coolant filters
• Plugged radiator.

Do not use soluble oils in the cooling system. The use of soluble oil will:

• Allow cylinder liner pitting
• Corrode brass and copper
• Damage heat-transfer surfaces
• Damage seals and hoses.

Supplemental coolant additives (SCA), or equivalent, are required to protect the cooling system from fouling, solder blooming, liner pitting, and general corrosion. The coolant filter is required to protect the cooling system from abrasive material, debris, and precipitated coolant additives.