My son inlaw not being a car person, has a 2000 mustang, having never put antifreeze in it sense he bought it ( just water ) it had a huge amount of rust in it, he came to me when he deveploped a crack in the aluminum/plastic rad at the top, so I had him pick up a new one, we flushed out enough rust on the first flushing to build the titanic, just with it running and the garden hose hooked up, when the water ran clear, I had him fill the system with 2 gallon of white vinegar, we ran it every day and circulated the mix for four days, dropped another titanic on the lawn and ran the garden hose back thru it again while running til it ran clear, everything is brite and clean like it was just cast steel, changed out radiator and filled with antifreeze.....in case of those that live in Calif, can`t buy anything stronger than toothpaste here anymore to flush out your radiator..