from my understanding,blown head gasket has certain things that happen.loss of power,smoke from exhaust and oil in coolant and coolant in oil.just check dipstick see if brown or white.check radiator cap see if brown oil is on the rubber,or floating.
radiator blockage to my understanding means you go for a 15 min drive and turn off car and check if the radiator bottom and top are the same temp. not the hoses,be-careful when doing this tho,or take it for a shop and have it tested.