Regarding coolants other than water, here is one viewpoint from Steward
Cooling about it.  Also a number of other tips about cooling that make for
interesting reading. Here is the URL

http://www.stewartcomponents.com/html/links/

Tech Tip #4 - Coolant, Fans, and Hoses

Coolant
UNEQUIVOCALLY WATER IS THE BEST COOLANT! We recommend using a corrosion
inhibitor comparable to Prestone Super Anti-Rust when using pure water. If
freezing is a concern, use the minimum amount of antifreeze required for
your climate. Stewart Components has extensively tested all of the popular
"magic" cooling system additives, and found that none work better than
water. In fact, some additives have been found to swell the water pumps
seals and contribute to pump failures.

In static cooling situations, such as quenching metal during heat treating,
softening agents (sometimes referred to as water wetting agents) will allow
the water to cool the quenched part more evenly and quickly. The part will
cool quicker, and the water will heat up faster. However, an automotive
cooling system is not static. In fact, the velocities inside a cooling
system are comparable to a fire hose forcing coolant against the walls of
the engine's water jackets. If the softening agents actually aided in
cooling the engine, the temperature of the coolant as it exited the engine
would have to be higher because it would have absorbed more heat.


Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com