Biggest issue is your running water only in radiator? The inside of your block radiator,and every part of your cooling system looks just like that pump.
I've been running a 50/50 mix since doing a Prestone flush, replacing the thermostat, and having the radiator re-cored. Just before I picked it up from my buddy last year, he replaced the heater core.
Edited to add: Still have a couple of original hoses in the system, but won't after this.
