i hate to say it at this point, but think about removing the thermostat when you pull the radiator, (you don't need to use a gasket for this), and flush as much crud out as you can before the new radiator goes in. you can also save the coolant you just put back in too. drain it into a new drain pan and when you pour it back in, strain it through cheese cloth or something. don't forget to put the thermostat back in
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