Radiator is out, what can I do in the meantime?

Pull the drain plugs in the block and flush it out good, maybe pop a frezout plug that is easy to replace and get the crud out. Might be time to flush out the heater core and new hoses, looks kind of crusty. Do it now and save problems later. Just throwing this out, I used muriatic acid for a flush in my radiator, 1 cup into the system full of WATER! Watch it will burn you pretty good if it gets on you. A lot of crap came out, I ran it till it got hot and flushed it out a few times and added baking soda to neutralize it. Helped a lot with a cooling issue I was having.