"Charlie" has Overheating probs- Here are my Clues and please chime in with opinions!

i always wondered about using something like evaporust in a cooling system, then a guy on another site brought it up, he said flush the system till its pretty clean, drain it, put 2 gallons of evapo rust in, run it till it gets warm, let it sit a day or 2. drain the system collecting the evaporust, then pour it through a filert cloth to catch the particles and you can reuse the evaporust. im not sure if he actually did it, but it would probably bebest to do it with no thermostat and no cap. you can buy it by the gallons or 5 gallons under other names. similar product. non toxic and only attacks rust. doesnt harm paint, other metals or rubber and plastic. so they say.