Park the vehicle on a level surface. Drain the oil and change the filter. Pour in 4.5 quarts of the correct weight oil and start the engine. Let it run for 2 minutes and shut down. Wait 30 minutes and check the oil level. Add as necessary to reach the full mark on the dip stick. You now know the capacity. Do not overfill.
8 quarts
7.5 quarts
8 quarts with filter
The capacity on the 3.6L v6 is 5.9 quarts.
The engine oil capacity is 7 1/2 quarts with the filter.
7.5 quarts plus filter
The 1996 Cadillac STS with a 4.6L V8 Northstar engine takes 7.5 quarts of 10W30 Oil (I know, A LOT, right?). Synthetic oil is recommended by Cadillac but I disagree, I have run both regular and synthetic oil and had no problems whatsoever. Hope this helps.
7.5 quarts of oil
7.5 quarts of oil
7.5 quarts
8 quarts
6 quarts