Leaking frost plugs

Tap them out with a screwdriver on the flange of the soft plug.
Grab them with vice grips pull them out.
Any garbage behind the plugs, shop vac, scrape clean it.
Napa sell a whole kit of brass soft plugs for like $20 bucks.
Install with the flange edge to block coated with permatex.
Let the permatex cure for 24 hrs before adding coolant.