Mate I think if you flush your motor regulary you will find the build up is not of salt, but a calcification of additives & minerals in our water supply, chlorine, fluride lime & so on. If you ever change your tap washers at home you will notice the same white substance, but soft. This is because the taps are turned on regulary, however this same water wil sit in your motor crystalizing until the next time you use it, continuing to build up more & more in time. There is a product call Macs Ultrafilm which has corrosion inhibitors, lubericants & filming agents, or even Salt Away is a similar product. I use Macs on my motor & have no problems, now that your cooling system is clean it certainly cant hurt to run this through & judge it for yourself.