46 Cooling System Regular Coolant Change Interval Replace the coolant every 250,000 miles (400,000 km), 4,000 hours or every two years, whichever comes first. Coolant SCA level must be tested at least twice per year or whenever coolant loss occurs. For maximum coolant system efficiency, test the system every 25,000 to 30,000 miles (40,000 to 56,000 km) depending on engine oil change interval or every 1,000 hours or maximum every 6 months (whichever comes first). The SCA level must be between 1.5 (Cummins: 1.2) and 3.0 SCA units per gallon (0.4 [Cummins: 0.3] and 0.8 SCA units per liter) of coolant. Note: Always dispose of coolant according to Federal or local regulations.
Take all used coolant to a recycling or waste collection center. Coolant Filter Change Intervals The charged coolant filter contains 8 units of SCA that are released slowly over time to maintain the recommended level during operation. WARNING Hot engine. Keep yourself clear of all hot engine parts and/or fluids. A hot engine and/or fluids can cause serious burns. Change the coolant filter at every 50,000 miles (80,500 km). If the SCA level tests above 3.0, DO NOT replace the coolant filter. When testing indicates that the SCA level has dropped below 1.5 units per US gallon (0.4 units per liter) start changing the filter with the oil changes again. Note:
Test the SCA level every 6 months (whichever comes first).