1993 Buick LeSabre Owner's Manual - Page 240

What Kind of Oil to Use: Look for three things: SG RECOMMENDED SAE VISCOSIN GRADE ENGINE OILS FOR BEST FUEL ECONOMY AND COW STARTING, SELECT THE LOWEST SAE VISCOSITY GRADE OIL FOR THE EXPECTED TEMPERATURE RANGE. " S G ' must be on the oil container, either by itself or combined with other quality designations, such as "SG/CC," "SG/CD," "SF,SG,CC," etc. These letters of show American Petroleum Institute (API) levels quality. HOT WEATHER LOOK FOR THIS LABEL NOTICE: If you use oils that don't have the"SG" designation, you can cause engine damage I covered by your warranty. SAE 1OW-30 above 0°F SAE 5W-30 (-18%) COLD WEATHER IF NEITHER SAE 5W-30 NOR SAE 1OW-30 GRADE OILS ARE AVAILABLE, SAE 30 GRADE MAY BE USED AT TEMPERATURES ABOVE 40 DEGREES F (4 DEGREES C). . DO NOT USE SAE 1OW-40, SAE 2OW-50 OR ANY OTHER GRADE OIL NOT RECOMMENDED