Freeze Plugs
#2
Just put another one in. Not to hard. they are flexible ans just press in with a light tapping of a small mallot. Be careful when you pull the old one so it's doesn't fall back into the block. If you can't get to it easily, you can put in a temporary one. they are rubber with a bolt and washer. Lub it slightly, push it in, tighten the knut. They last a while, but not for ever.