1993 Buick Park Avenue Owner's Manual - Page 255

What Kind of Oil to Use: Look for three things: SG RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS FOR BEST FUEL ECONOMY AND COLD STARTING, SELECT THE LOWEST SAE VISCOSITY GRADE OIL FOR THE EXPECTED TEMPERATURE RANGE. "SG" 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 show American Petroleum Institute (API) levels of quality. HOT WEATHER LOOK FOR THIS LABEL If you use oils that don't have the "SG" designation, you cancauseenginedamagenot covered by your warranty. - I I SAE 1OW-30 PREFERRED SAE 5W-30 above 0°F (-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