1993 Oldsmobile Silhouette Owner's Manual - Page 229

Grade E For best fuel economy and cold starting, select the lowest SAE viscosity grade oil for the expected temperature range. S A E 5W-30 (3.X V6 Engine) SG "SG" must be on the oil container, either by itself or combined withother quality designations, suchas "SGICC," "SGICD," "SF, SG, CC," etc. These letters show American Petroleum Institute(API) levels of quality. As shown in the viscosity chart, SAE 5W-30 is best for your vehicle. However, you can use SAE 1OW-30 if it's going to be0°F (-18°C) or above. These numbers onan oil container show its viscosity, or thickness. Do not use other viscosity oils such as SAE 1OW-40 or SAE 20W-50. If you use oils that don't have the SG designation? you can cause engine damage not covered your by warranty.