1998 Buick LeSabre Owner's Manual - Page 261

Engine Oil CHECK O1 LEVEL If the CHECK OIL LEVEL light on the instrument panel comes on, it means you need to check your engine oil level right away. The engine oil dipstick is right behind the engine fans and in front of the engine oil fill cap. Thetop of the dipstick is a round, yellow loop. Turn off the engine and give the oil a few minutes to drain back into the oil pan. If you don't, the oil dipstick might not show the actual level. For more information, see "Check Oil Level Light" in the Index. You should check your engine oil level regularly; this is an added reminder. It's a good idea to check your engine oil every time you get fuel. In order to get an accurate reading, the oil must be warm and the vehicle must be on level ground. 6-11