I'd recommend running the engine "as is" for several warm up/cool down cycles before using any sort of stop leak. A seep leak will usually self-seal, particularly on a low pressure cooling system where there's not a great deal of stress on gasketed joints. Bar's Leaks is a great sealer, but it turns the coolant a nasty-looking gray color!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!