1997 GMC Suburban Owner's Manual - Page 298

RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS FOR BEST FUEL ECONOMY AND COLD STAR'IING, SELECT THE LOWEST SAE VlSCOSlTV 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 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-50. HOT WEATHER "C :. t 38 t 27 t 16 LOOK FOR THIS SYMBOL 1 NOTICE: Use only engine oil with the American Petroleum Institute Certified For Gasoline Engines "Starburst" symbol. Failureto use the recommended oil can result in engine damage not covered by your warranty. GM Goodwrench@oil meets all the requirements for your vehicle. t 4 -7 - 18 PREFERRED SAE sw-30 WEATHER DO NOT USE SAE 2OW-50 OR ANY OTHER G A M E OIL NOT RECOMMENDED coul 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 cold starting and better protection for your engine at extremely low temperatures. 6-16