Last September discovered head gasket leak. Tried to plug with "Alumaseal Stopleak." (Stupid idea)! Problem persisted. Three weeks later I flushed cooling system & tried to plug leak with "Bar's Leak Head Gasket Repair." Leak seemed plugged, but 8 months later engine overheated & radiator coolant was discovered to be way too low. Replaced coolant, kept radiator filled on inspection.
Ten days ago added Subaru Cooling System Conditioner. Coolant began backing up into coolant reservoir, nearly filling it to the top every 75 miles, with
foam floating near the top. Five days ago tried using "BAR'S LEAKS Head Gasket Repair." Looked good! No steam or water exiting tailpipe, and level of water in coolant reservoir remained steady — BUT — was only able to get 4 quarts of fluid into radiator! Engine now overheats in 15 minutes. Removed thermostat — no change. Top radiator hose hot, bottom hose cold. My guess — I plugged radiator with all the gunk I poured in. Can I flush that crap out with some sort of commercial additive, or should I just get a new radiator?