1997 GMC Sonoma Owner's Manual - Page 251

RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS _ _ ~ ~I I -- FOR BEST FUEL ECONOMY AND COLD STARTING, SELECT THE LOWESTSAE VISCOSITY GRADE OIL FOR M E EXPECTED TEMPERATURE RANGE. As shown in the chart, SAE SW-30 is best for your vehicle. However, you can use SAE 1OW-30 if it's going to be 0°F (- 18°C) or above.These numbers on an oil container show its viscosity, or thickness. Do not use other viscosity oils, such as SAE 20W-SO. HOT WEATHER LOOK F R mS O l SYMBOL NOTICE: Use only engine oil with the American Petroleum Institute Certified For Gasoline Engines "Starburst" symbol. Failureto use the recommended oilcan result in engine damage not coveredby your warranty. GM Goodwrench@ oil meets all the requirements for your vehicle. r 1-30 REO I f 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 cold starting and better protection for your engine at extremely low temperatures. 00 NOT USE SAE 2OW-50 OR ANY OTHER GRADE O L NOT RECOMMENDED 6-13