you have to drain the antifreeze/coolant so it would be wise.
Petcock on bottom or radiator or remove lower hose.
Remove and clean the petcock. Replace and if it still leaks, replace with a new petcock.
I would just leave it alone. Remove the lower radiator hose to drain and flush the radiator. You don't really need the petcock.
Open the petcock or remove the lower radiator hose from the radiator.
Normally on the bottom of the radiator. If none is there then remove the lower radiator hose to drain the radiator.
I just ran into this problem. The petcock is plastic and has a metal pin protruding thru the side. This pin rides in a "track" and locks the petcock into place when you put it back in. I broke the pin removing the petcock and had to remove the radiator to repair it. You may be able to do this with the radiator in place. See if you can feel the track and if you replace the pin, you will feel it lock into place when you reinstall the petcock. The pin can only protrude on one side of the petcock so that the petcock will seat correctly. Good luck.
Typically there is a petcock valve on the lower left side of the radiator, unscrew the petcock to drain the radiator. On radiators without a petcock, you would remove the lower hose to drain the system. (Quite messy!)
Drain or petcock should be a the lower of rear of radiator or remove lower radiator hose
If there is no drain petcock then just remove the lower radiator hose.
Remove plug or open petcock at the bottom or rear of the radiator or remove the lower radiator hose
Should be at the bottom or rear of the radiator or remove the lower radiator hose
Most of these do not have one.You must remove the lower radiator hose to drain the radiator.