Take the radiator to a radistor shop and have it rodded out or replace it. but first pull the thermostat and check it in a double boiler and see if and when at what temp. it opens. If it is bad replace it but if you do, first be fore you install the new one test it. If the thermostat is ok then do the rad. there really isn't much you can do yourself other than removing the rad. and taking it to the shop. One thing to think of ,if the engine overheats and you warp the head you will be in for a much greater cost. Good luck ,Gary Portland Ore.