2003 Pontiac Grand Prix Owner's Manual - Page 245

What Kind of Engine Oil to Use A A Oils recommended for your vehicle can be identified by looking for the starburst symbol. * SAE 1OW-30 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 choose to perform the engine oil change service yourself, be sure the oil you use 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 viscosity chart. m 3100 I - .- Engine I 3800 V6 or 3800 V6 Supercharged Engine The engine oil fill cap will have one of these symbols on it, depending on the engine. It is located on the front of the engine, near the center of the engine compartment and the yellow-looped engine oil dipstick. See Engine Compartment Overview on page 5-12 for more information on location. Be sure to fill it enough to put the level somewhere in the proper operating range in the cross-hatched area. Push the dipstick all the way back in when you're through. 5-20