I'm not ASE certified or anything, but i would say on the bottom of the oil pan?!?!?
Honestly if you don't know where the drain plug is, don't mess with the vehicle then!
on the oil pan
bottom passengers side of radiator
2006 Chevrolet Truck Silverado 1500 2WD 5.3L SFI HO 8cylThe Spark Plug Gap.040 (In thousandths of an inch)
Below the oil pan. If you do not know you should not touch it.
Locate the plug on the bottom of the radiator to drain it. Put some radiator cleaner in and drain it again.
Lower Side or bottom of oil pan
Should be on the bottom or side of the oil pan
The cooling system on these vehicles is drained by detaching the lower radiator hose from the radiator. The radiator doesn't have a drain plug.
The radiator drain plug on a 1989 Chevy C1500 Silverado is on the bottom of the radiator.
It is always in the bottom rear side of the oil pan, sometimes it's on the bottom side too.
There is no drain plug, you have to remove the bottom hose.