Waterless coolant
 

"Your cooling fan doesn't need to start as often" -> draws less power from the battery -> lightens load on the alternator -> saves fuel ????

Waterless Coolant Improves Engine Life, Boosts MPG 10 Percent

Anyone thinks this really saves as much fuel as claimed?

I have an efficient engine. So efficient that it doesn't produce too much waste heat most of the time. My hypermiling techniques further increase the efficiency to the point that during the colder part of the year I need to fully block both of my grille openings and add thermal insulation, and the engine still barely gets up to temp.
Would this waterless coolant reduce my fan usage?

Even if I had a less efficient engine (like a gasser, maybe?) and didn't hypermile, I couldn't just pour the stuff in and be happy. I'd have to rewire/reprogram the fan and its electronics to turn on at a higher temperature. And maybe replace the thermostat, too. Then the engine would be kept at a higher temp, maybe increasing efficiency, but more likely increasing knocking. So the timing should be changed. Oh, and then the seals and other elements in the engine and cooling system may not have been made to withstand higher temperatures for longer durations, so they might fail sooner.
OK, I might be exaggerating, but those are some of the problems I can think of.

What I'm getting at is that just replacing your coolant with a waterless version most likely won't reduce your fuel consumption by 10% just like that. The changes need to be a little deeper.

Interesting, however, I'm pretty skeptical of the 10% claim. I could see where the coolant could enable a gain, but I don't see where it would benefit in and of itself. Your coolant temperature is determined by your thermostat, not by the coolant itself. And the amount of heat that leaves the cylinders and goes to the coolant is determined by the cylinder wall temperature which, again, is not affected by the cooling medium. Also, max temperature is determined by the design of the block, head(s) as well, so you can't just switch to a different coolant and run 300 deg F coolant temps. If the coolant had a high heat capacity I could see where one could get away with a smaller water pump and save a little fuel, but that would require putting in a new pump. Also, a high heat capacity would mean that the engine would take longer to warm up, this loosing efficiency. A less viscous coolant might also help because the coolant pump wouldn't have to work so hard, however, I don't see anything getting much less viscous than water/glycol.

So, I guess I see how one might redesign the engine to work with a different coolant and see a benefit, but I don't see a benefit from just putting a different coolant in.

The only direct benefit I see is with corrosion.

there is a thread on this......somewhere....i remember reading it,,,,

I have used the Evans Waterless in my truck for years.

It's something I can forget about. Change it every half-million miles. No corrosion or cavitation problems like with water/glycol. Lower pressure in hoses. My main problem now is dry rotting the hoses on the outside.

Sadly, I don't think it does much to improve MPG.

...the SAE paper projected a 2-4% FE increase with change from 190ºF to 215ºF thermostat, but didn't get it:

http://www.evanscooling.com/assets/p...vans-final.pdf

Interesting, I did notice in the first paragraph they locked the fan on, eliminating a source of possible gain.

Water is the most efficient coolant you're likely to come across. It has a low viscosity (easy to pump), a fair heat capacity, but more important, very high thermal conductivity. Most liquids you could use for coolant fail to beat water in 2 of 3 areas.

Antifreeze for instance raises viscosity and lowers conductivity, even if it raises heat capacity.

These days everything is aluminum, so there isn't even any corrosion benefit right? Antifreeze originally prevented corrosion in mixed metal loops.
I'm pretty sure antifreeze lowers heat capacity, the only purpose it serves is freezing point depression (and boiling point...elevation? is that what it's called?).
Ethylene Glycol Heat-Transfer Fluid