1998 Pontiac Trans Sport Owner's Manual - Page 342
1998 Pontiac Trans Sport Manual
Page 342 highlights
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 anyoil which does not carry this Starburst symbol. RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS FOR BEST FUEL ECONOMY AND COLD STARTING, SELECT THE LOWEST SAE VISCOSITY GRADE OIL FOR THE EXPECTED TEMPERATURE RANGE. If you change your own oil, be sure you use oil that has the Starburst symbol on the front of the oil container. 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: HOT WEATHER LOOK FOR T I H S SYMBOL 7 SAE 5W-30 PREFERRED / COLD WEATHER DO NOT USE SAE 2OW-50 OR ANY OTHER GRADE OIL NOT RECOMMENDED 6-13