Engine Lubrication: Specifications

Engine Oil Quality
Oils of the proper quality for the vehicle can be identified by looking for the STARBURST symbol. The STARBURST symbol indicates that the oil has been certified by the American Petroleum Institute (API), and is preferred for use in gasoline engines.

Engine Oil Viscosity

NOTE: Using oils of any viscosity other than those recommended could result in engine damage.

When choosing an oil, consider the range of temperatures the vehicle will be operated in before the next oil change. Then, select the recommended oil viscosity.
The recommended oil viscosity for all vehicles when the temperature is above 0 °F (-18 °C) is SAE 10W-30.
Engine oil viscosity (thickness) has an effect on the fuel economy and the cold-weather operation (starting and oil flow). Lower viscosity engine oils can provide better fuel economy and cold-weather performance. However, higher temperature weather condition require higher viscosity engine oils for satisfactory lubrication. When the temperature is consistently above 0 °F (-18 °C), SAE 10W-30 can be used. SAE 20W-50 or oils of other viscosity rating or quality designations are NOT recommended for use in any GMC vehicle at any time.