2002 Buick Century Owner's Manual - Page 262

NOTICE: Don't add too much oil. If your engine has so much oil that the oil level gets above the cross-hatched area that shows the proper operating range, your engine could be damaged. When to Add Engine Oil If the oil is at or below the ADD mark, then you'll need to add at least one quart of oil. But you must use the right kind. This part explains what kind of oil to use. For engine oil crankcase capacity, see "Capacities and Specifications" in the Index. The engine oil fill cap is located toward the front of the engine near the engine oil dipstick handle. See "Engine Compartment Overview" in the Index for more information on location. 6-12