C8.3 Commercial Marine and Ind [...] Lubricating Oil Recommendations and Specifications Section V - Maintenance Specifications Page V-11 The use of low-viscosity oils, such as 10W or 10W-30, can be used to aid in starting the engine and in providing sufficient oil flow at ambient temperatures below -5°C [23°F]. However, continuous use of low-viscosity oils can decrease engine life due to wear. Refer to the accompanying chart. The API service symbols are shown in the accompanying illustration. The upper half of the symbol displays the appropriate oil categories. The lower half can contain a description of oil energy conserving features.
The center section identifies the SAE oil viscosity grade.