1998 Pontiac Bonneville Owner's Manual - Page 267

As shown in the chart,SAE 1OW-30 is best for your vehicle. However,you can useS A E 5W-30 if it's going to be colderthan 60 "F (16"C) beforeyour next oil change. When it's very cold, you should useS A E 5W-30. These numberson an oil container show its viscosity, or thickness. Do not use other viscosity oils, such as SAE 20W-50. Engine Oil Additives Don't add anythingto your oil. Your dealer ready to is advise if youthink something should be added. When to Change Engine Oil If any oneof these is true for you, use the short tripkity maintenance schedule: 0 Most tsips are less than to 10 miles (8 to 16 lun). 5 This is particularly important when outside temperatures are below freezing. 0 NOTICE: Use only engine oil with the American Petroleum Institute Certified For Gasoline Engines "Starburst" symbol. Failure use the to recommended oil can result in engine damage not covered by your warranty. GM Goodwrench@ oil meets the requirements for all your vehicle. If you are in an area where the temperature falls below -20°F(-29"C), consider using either S A E 5W-30 an synthetic oilor an S A E OW-30 oil. Both will provide easier cold starting better protection for your engine and at extremely low temperatures. 0 0 Most trips include extensive idling (such as fiequent driving in stop-and-go traffic). Most trips are through dusty areas. You frequently tow a trailer or use a carrier on top of your vehicle. 0 The vehicleis used for delivery service, police,a i tx or other commercial application. Driving under these conditions causes engine oil to break down sooner. any oneof these is true for your If vehicle, then you need to change your and filter oil every 3,000 miles (5 000 km)or 3 months -- whichever occurs first. 6-16