Cummins / CAt both offer a ph test strip and additive to correct the coolant in long life coolant... we use it in our engines... we test the coolant for freezing point, use the test strip and add back the additive... usually 8-12 oz package and its good to go... .
We only use a non-silicate coolant and distilled water when and if we have to either add or change...
We just don't change the coolant... . we let it run... . and check it... . so far we haven't had coolant or water pump problems... the trucks I have sitting here now must have a combined mileage of over 1 M miles... .
i have toyed with the idea of putting a cat cooling system conditioner/filter set-up on my truck. Its just a spin on filter base with the conditioner impregnated onto the filter media. Bob is right, we don't have liners/sleeves in these blocks. But, the coolant conditioner/filter would extend the life of my cooling system. One day here soon, i'm gonna sit down and run all the specs. And make sure the conditioner/filter is compatiable with the hoat.