Quick add, I pulled up the sales rep's sheet for Fleetguard coolants, red has anti corrosion inhibiters in it for liner pitting resistance, however didn't say anything about cross metals.
I did find this however for their blue coolant...
-Fully formulated extended life coolant (antifreeze) with dual
borate, phosphate buffer and low silicate formulation for use
in all heavy-duty diesel and gas engines.
-Life-of-the-Engine, 1,000,000-mile (20,000 hr) coolant.*
-Protects against liner pitting, and provides solid corrosion protection
for aluminum, cast iron, copper, brass and solder. Contains proprietary
scale inhibitors.
-Compatible with DCA4 liquid or DCA4 chemical filters.
-Available in both ethylene or propylene glycol base as either a
50/50, 60/40, premix or concentrate.
-Meets ASTM D3306, ASTM D6210, TMC RP 329.
Their pink (fleetcool EX) alos lists good for brass and other mixed metals...
Now obviously I'm not running coolant for a million miles... But might be a good alternative? I'm trying to decide what to put in my truck, as it has the same coolant I put in it back in 2012, but I've only put maybe 10k miles on it since then.