Bottom of the engine on the oil pan.
petcocks are usually located on one of the bottom corners of the radiator, on the back (engine side).
It is in the oil pan and that is bolted on the bottom of the engine. Just look around the bottom of the oil pan and you will see a bolt in it. And that will be it.
It's on the right bottom side of the radiator facing the engine.
on the oil pan
Honestly if you don't know where the drain plug is, don't mess with the vehicle then!
bottom passengers side of radiator
The bottom of the engine. There is a plug that you drain the oil out of. that plug is in the pan.
Below the oil pan. If you do not know you should not touch it.
The drain plug would be located at the lowest point on the oil pan. It usually takes a 15mm wrench to remove.
It is on the back side of the oil pan on the drivers side. Look for the lowest point of the oil pan and you will see it.
Locate the plug on the bottom of the radiator to drain it. Put some radiator cleaner in and drain it again.