I made these two tools from plumbing stuff available at Lowes. the longer one is the inlet, with a valve to control flow.
Get the car in the air and remove the underpanels. Disconnect the rubber coolant hoses on the driver side where they go into the center tunnel. You'll need another short rubber hose to connect to the metal pipe. Start by pushing water towards the radiators. Once the water runs clear, flip the hoses and push water towards the engine. You're going to run a lot of water, but water's cheap. Oil in the system will destroy the rubber hoses. Of course, if you don't get all the little pieces of plastic impeller out, they are sure to jam up in the heads and cause another hot spot.