So it's OK to do this cooling system overhaul without replacing the radiator, water pump, and fan clutch? Or should I really do these as preventative measures?
208k on the odometer and I don't know if this has ever been done. No overheating/cooling issues that are visible.
Well if you do it without replacing the radiator, water pump, or fan clutch, that's not really overhauling the cooing system. In fact, if you don't replace those parts, what are you even replacing at all?
With 208k and no history of ever having done the cooling system, I think you'd be pretty foolish not to at least have this on your radar (and that includes all of it).