1996 Pontiac Bonneville Owner's Manual - Page 259

When to Add Oil If the oil is at or below the ADD mark, then you'll need to add some oil. But you must use the right kind. part This explains what kind of oil to use. For crankcase capacity, see "Capacities and Specifications" in the Index. What Kind of Oil to Use Oils recommended for your vehiclecan be identified by looking for the "Starburst" symbol. This symbol indicates that the has been certified by the American oil Petroleum Institute(API). Do not use any oil which does not carry this Starburst symbol. E I NOTICE: : Don't add too much oil. I your engine has f so much oil that the oil level gets above the cross-hatchedarea that shows the proper operating range, your engine could be damaged. I The engine oil cap is behind the engine oil dipstick fill and engine fans. I Just fill it enough to put the level somewhere in the proper operating range.Push tKe dipstick all the way back in when you're through. 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, besure.the oil put into your engine is American Petroleum Institute certified for gasoline engines. You should also use the proper viscosity for your oil vehicle, as shown in the following chart: