I do not change coolant regularly, it has not been changed in 19 years in my JD tractor (it is around 70 or 80% anitfreeze) and never been change in my 2000 or my wifes 2000 and all is bright and clear and overflow tanks are spotless too (they are bewtween 65 and 70% consentration) My burb has not been changed for 8 years and overflow is clean and pull cap it is clean too. I must be just making all of this up huh and all of the extra aluminum in engien assembly has not extra issues either huh.
Again you confirm your TOTAL lack of understanding of coolant mixture ratios and the reactivity of water in solution and how its consentration level relative to glycol and its additives in suspension. (water is consider one of the most power solvents out there in that given enough time it will dissolve just about anything) I remember when cars used to come with but about 40/60 (40% antifreeze to protect to about 18 to 20 below) and those babies rusted bad in but a few years. The only reason one would not use pure antifreeze is because in a solution with 30% water it has its lowest freezing point and freezes at about 9 degrees (slushes actually as it never freezes solid) in pure state. Yes water can absorb more heat than glycol per pound but in a closed loop cooling system it is not really a issue because you will still get the same BTU dump thru radiator because the coolant will cool a bit more with high glycol content before it leaves radiator and be able to absorb the same amount of total BTUs because a lower starting temp. Some have claimed that water system run a bit cooler but I have never had that problem or seen it but possibly in a very marginal system in "might help" a little.