This SAE Standard defines the limits for a classification of engine lubricating oils in rheological terms only. Other oil characteristics are not considered or included.
This revision changes the cold cranking simulator (CCS) viscosity limits in SAE J300 from critical to non-critical specifications, as defined in ASTM D3244. OEM members of the Engine Oil Viscosity Classification (EOVC) Task Force have advised the Task Force that modern engines can start at viscosities above the current CCS limits in J300; therefore, oils formulated near the upper CCS limit should not compromise engine starting performance at low temperatures. From an engine durability perspective, the most important low temperature oil performance issue is pumping, to ensure that the oil can circulate after the engine fires. A benefit of this change is that it provides more flexibility to use modern, high VI (Viscosity Index) base oils in the formulation of fuel-efficient engine oils in popular viscosity grades such as SAE 5W-30 and SAE 10W-30.