1998 GMC Jimmy Owner's Manual - Page 281

What Kind of Engine Oil to Use Oils recommended for your vehicle can be identified by looking for the "Starburst" symbol. This symbol indicates that the oil has been certified by the American Petroleum Institute (API). Do not use any oil which does not carry this Starburst symbol. If you change your own oil, be sure you use oil that has the Starburst symbol on the front of the oil container. GRADE ENGINE OILS FOR BEST FUEL ECONOMY AND COLD STARTING, SELECTTHE LOWEST SAE VlSCOSlTV GRADE OIL FOR THE EXPECTED TEMPERATURE RANGE. HOT WEATHER LOOK FOR THIS SYMBOL If you have your oil changed for you, be sure the oil put into your engine is American Petroleum Institute certified for gasoline engines. You should also use the proper viscosity oil for your vehicle, as shown in the following chart: L SAE 5W-30 PREFERRED COLD WEATHER DO NOT USE SAE 2OW-50 OR ANY OTHER GRADE OIL NOT RECOMMENDED 6-12