C Series Lubricating Oil System - Overview Section F - Familiarization Page F-7 Lubricating Oil System - Overview (007-999) General Information Use Cummins Premium Blue® 15W-40 multiviscosity oil, or equivalent, that meets API Classification CE for turbocharged engines. NOTE: CC/CD or CD/SF engine oils can be used in areas where CE oil is not yet available; however, the oil drain interval must be reduced by 50 percent. CAUTION Limited use of low-viscosity oils, such as 10W-30, can aid in starting the engine and providing sufficient oil flow at ambient temperatures below -5°C [23°F]. However, continuous use of low-viscosity lubricating oils can decrease engine life.
Refer to the accompanying chart. Lubricating Oil System - Diagnosing Malfunctions Make sure to check items related to oil pressure, such as gauges, high and low oil level, excessive contamination, and oil viscosity. High Oil Pressure High oil pressure usually occurs after the engine is first started in cold weather. The lubrication system does not have a cold start relief valve. The pressure regulating valve components are machined to a size that will relieve the excessive pressure created by cold engine oil. The engine will have high oil pressure if the regulator sticks shut. Inspect the regulator for freedom of movement. Oil Pressure Regulating Valve