6 quarts according to my manual 5w-30
There is this wonderful thing called an owners manual. It lists such items as oil capacity
6 qts. for both the 3.7 and 5.3 liter engines.
5 quarts (with an oil filter change)
6 quarts synthetic 5W-30 Filter is an AC Delco PF46, FRAM PH3506, etc
It takes 6 quarts of 5w30
3.5 quarts
6.4 quarts of engine oil with filter change.
You will need to drop the oil pan to change the oil pan on a Hummer 2. The oil pan is located in inside the oil pan. You also need to first drain the oil pan of the old oil before you drop the pan.
7 quarts.
If you have the new V-6 engine, (non compressor engine) then the capacity is 8.5 qts. with oil filter change.
6.5 quarts with filter change.
6 qts with filter change.