Re: Where's the radiator drain plug?
Not all radiators have one.
You can remove the lower radiator hose.
BTW - the sealant? Can easily make your small problem a bigger one.
Where does it leak?
335K miles on original motor and tranny (only motor work 2 x LIM replacement), Monroe SensaTrac struts front and back (new at approx. 300K miles), and Alero discs in back. LS fogs added with custom wiring. HID high beams, HIR low and halogen fogs. Raybestos Pro Grade front rotors and Bendix D747 ceramic pads on front.
Addendum: Rest in peace. Surge tank blew, motor overheated, I think she's lived a long and useful life.