Where is oil plug on a 2001 silverado with 5.3 liter engine?

The oil drain plug on a 2001 Silverado with a 5.3L engine is located on the bottom of the oil pan. The oil pan is the large, somewhat rectangular metal part underneath the engine. You'll need to get under the truck to access it. It's usually a fairly large bolt (often 15mm or 14mm – check your owner's manual for the correct size). Be careful as the oil will be hot if the engine has been recently run. Have a drain pan ready to catch the oil.