Coolant increases the boiling point but runs HOTTER than water..... yet am thinkin 4 ounces of coolant will help prevent rust. Dunno about water wetter but have heard its good stuff.

What nobody ever does is flush the system enough.... i like 6-8 hr valvoline radiator flush combined with an all day drive, say to remote fishing grounds. And yes, the prestone $3.99 garden hose flush kit is decent.... you can even hook it up on feed line to heater core then umplug the return line to cylinder head to power flush the heater core - then move it around to power flush the cylinder head routing water through the radiator too. Flushin the system is fun.

Btw, anybody ever run with NO thermostat at all in Summertime??

Coolant system efficiency is something thats easily measured and appreciated. I guess everybody has hit the heater levers in July to cool the engine by 10-15 degrees at one time or another.

And maintaining the cooling system is something the DIY owner can do a helluva lot better than any garage can.