Hey, I bought a 96 bronco in august of 2009. The radiator was full of rust I flushed most of it out ,but ended up buying new radiator,water pump, new fail safe termostat and new fan clutch. And have flushed the coolent sytem many times using flush machines and in the back yard with the water hose. The other day i was helping a car that got stuck in sand and let my truck runing and the a/c on for mabey 15 minutes and it started to overheat (it was also about 97 degrees outside), the gauge got about 3/4 the way up and the truck started missing so i shut it off. The water was boiling and pouring out. I let it cool down and has ran great since, but i noticed the coolent was brown so i flushed it again. I must have rust in the block how do i get it out, i have flushed it again and again. An old man told me to put baking soda in the radiator cause it neurtrulizes acids and will break down rust so i am trying that any one got any ideas?