I don't know if they are still available but they use to make a flush kit for cars and trucks which had a plastic tee fitting that went in outlet side of the heater hose and let you reverse flush the system back through the radiator. I have found when flushing the cooling system it is good to take the two heater hoses loose and with a small piece of pipe connect them togather to prevent pushing all the engine sludge back into the heater core. Tee connection allowed you connect a garden hose to the system to provide a constant flow of clean water. A replacement radiator may be cheaper than a re-core in most cases due to the labor involved. Good luck and let us know how it works out.
