The engine oil capacity for a 1997 Oldsmobile 88 depends on the engine it has. There were a few different engine options available that year. To be certain, you must check your owner's manual.
However, a good estimate is between 4.5 and 5 quarts. This is a common range for V6 engines of that era. You will need to add oil gradually, checking the dipstick frequently until you reach the "full" mark. Don't overfill.
