1997 Buick Century Owner's Manual - Page 280

When to Chang( Cngine Oil If any one of these is true foryou, use the short tripkity maintenance schedule: Most trips are less than 5 to 10 miles (8 to 16 km). This isparticularly important when outside temperatures are below freezing. Most trips include extensive idling (such as frequent driving in stop-and-go traffic). Most trips are through dusty areas. (See "Change Oil Soon" Light in the Index.) What to Do with Used Oil Did you know that used engine oil contains certain elements that may be unhealthy for your skin and could even cause cancer?Don't let used oil stay on your skin for very long. Clean your skin and nails with soap and water, or a good hand cleaner. Wash or properly throw away clothing orrags containing used engine oil. (See the manufacturer's warnings about the use and disposal of oil products.) Used oil can be a real threat to the environment. If you change your own oil, be sure to drain free-flowing oil all from the filter before disposal. Don't ever dispose of oil by putting it in the trash, pouring it on the ground, into sewers, or into streams or bodies of water. Instead, recycle it by taking it to a place that collects used oil. If you have a problem properly disposing of your used oil, ask your dealer, a service station or a local recycling center for help. You frequently tow a trailer or use a carrier on top of your vehicle. The vehicle is used for delivery service, police, taxi or othercommercial application. Driving under these conditions causes engine to break oil down sooner. If any one of these is true for your vehicle, then you need to change your oil and filter every 3,000 miles (5 000 k ) 3 months -- whichever occurs m or first. (See "Change Oil Soon"Light in the Index.) If none of them is true, use the long triphighway maintenance schedule. Change the oil and filter every 7,500 miles (12 500 k ) 12 months -- whichever m or occurs first. Driving a vehicle with a fully warmed engine under highway conditions causes engine oil to break down slower.