1997 Buick Century Owner's Manual - Page 279

RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS . .~ FOR BESTFUELECONOMYANDCOLDSTARTING,SELECTTHELOWEST 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 low-30 if it's going numbers on an oil to be 0" F (- 1 8 "C) or above. These container show its viscosity, or thickness.Do not use other viscosity oils, such as SAE 20W-50. HOT WEATHER LOOK FOR THIS SYMBOL NOTICE: Use only engine oil with the American Petroleum Institute Certified For Gasoline Engines "Starburst" symbol. Failure to use the recommended oil can result in engine damage not covered by your warranty. ! t40 + 20 - SAE 1OW-30 I GM Goodwrench@ oil meets all the requirements for your vehicle. COLD WEATHER 00 NOT USE SAE 2OW-50 OR ANY OTHER GRADE OIL NOT RECOMMENDED 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. Engine Oil Additives Don't add anything to your oil. Your Buick dealer is ready to advise if you think something should be added. 6-13