Radiator Issues 06 Forester

Starts out in late spring. .radiator had a presure test and failed put in new rad after market drove fine for a month or 2 went on a trip to kelowna stop on side of road head back to town a/c pushing hot air . Pull over at garage they have no coolest nor us so we filled with water drove fine for miles and miles needed to only add 1 more cup before climbing the Coquohala to come back to island ran pretty fine sucky fuel mileage no water in oil then it started running really bad and rough in Oct. .. changed head gaskets and head then turns out Crack in block put in new motor. ... temp gage up to mid le imediantly need to add water /coolant constantly. ... ... any ideas we have just picked up a subaru rad from a junkyard changing that out next.. we have tried new thermostat aswell were actually really fed up lol any ideas will be considered thank so much in advance