VC9 is what you need to remove rust, sludge and other crap from your cooling system. Just a word of warning, if your 6.0 oil cooler is working properly and your deltas are within the acceptable range, do not use this product or Restore Plus. They *can* remove particles from the system that clog the thin channels in the oil cooler. If you choose VC9, flush the oil cooler in reverse order until oil flows freely through it. Backflushing the radiator is easy and saves you from nasties like boiling coolant and blown head gaskets. Just do it! You bought a men's truck that needs a little man's work.