2011 Buick Lucern Owner's Manual - Page 305

When to Add Engine Oil Notice: Do not add too much oil. Oil levels above or below the acceptable operating range shown on the dipstick are harmful to the engine. If you find that you have an oil level above the operating range, i.e., the engine has so much oil that the oil level gets above the cross-hatched area that shows the proper operating range, the engine could be damaged. You should drain out the excess oil or limit driving of the vehicle and seek a service professional to remove the excess amount of oil. See Engine Compartment Overview on page 6 ‑ 14 for the location of the engine oil fill cap. 3.9L V6 Engine 4.6L V8 Engine If the oil is below the cross-hatched area at the tip of the dipstick, add 1 L (1 qt) of the recommended oil and then recheck the level. See "Selecting the Right Engine Oil" in this section for an explanation of what kind of oil to use. For engine oil crankcase capacity, see Capacities and Specifications on page 6‑116. Add enough oil to put the level somewhere in the proper operating range. Push the dipstick all the way back in when through. 6-19