1998 Buick Century Owner's Manual - Page 273

RECOMMENDED SAE VlSCOSlTT GRADE ENGINE OILS FOR BEST FUEL ECONOMY AND COLU STARTING, SELECT THE LOW SAE VISCOSITY GRADE OIL FOR THE EXPECTED TEMPERATURE RANGE. As shown in the chart, SAE 5W-30 is best for your vehicle. However, you can use SAE 1OW-30 if it's going numbers on an oil to be0°F (- 18O C) or above. These container show its viscosity, or thickness.Do not use other viscosity oils, such as SAE 20W-50. HOT WEATHER + 100.. I LOOK FOR MIS SYMBOL NOTICE: Use only engine oil with the American Petroleum Institute Certified For Gasoline Engines "Starburst" symbol. Failure use the to recommended oil can result in engine damage not covered by your warranty. I j+27 - + 16 - +4 - -7 l GM Goodwrench@ oil meets all the requirements for your vehicle. , ';; COLD WEATHER i, I SAE Sw-30 PREFERRED If you are in an area where the temperature falls below -20°F (-29"C), consider using either an SAE 5W-30 synthetic oil or an SAE OW-30 oil. Both will provide easier coldstarting and better protection for your engine at extremely low temperatures. DO NOT USE SAE 2OW-50 OR ANY OTHER GRADE OIL NOT RECOMMENDED 6-13