in your opninion?

which coolant is THE COOLEST available..such as engine ice?? water wetter? others? thanx-josh

Engine Ice I is propylene glycol, the same as Prestone LowTox, Sierra Antifreeze. The LowTox, and Sierra are a whole bunch cheaper than engine ice, and do the same thing. They are not blue though, just the same old green.


so its really no different than standard antifreeze?..i may already have basically the same thing as engine ice in my bike already?..i used some green antifreeze..proplyn glycol or how ever its spelled..thanx

THE COOLEST available is straight water (distilled is best) with surfactant. It has better heat transfer characteristics than PG or EG, but provides no corrosion resistance. Adding a bit of water wetter (surfactant) will protect against corrosion and actually increase the heat transferability of water. The only problem is that the boiling point will be determined solely by the pressure cap, but as long as you don't run over about 230 degrees, you should be OK.

I used this combo last year and only puked coolant on the slowest, most technical trails.

I will not dispute the many benefits of Evans NPG, although it and the required system flush are very expensive. Claims of increased efficiency are undoubtedly due to the reduction in nucleate boiling which can also be accomplished with water and a surfactant, however, I can find no claims that its' thermal conductivity is greater than, or even close to that of water. This means, all else equal, that your system will run hotter with NPG than with water. So, like I said, as long as you don't have a problem keeping fluid in the rads, you will run coolest with distilled water and a surfactant simply because the heat transfer characteristics of water can't be beat.

The benefits of a coolant such as Evans is that in a situation where high temperatures are inevitable, its very high boiling point and resistance to "spot boiling" are helpful. (Spot boiling is nucleate boiling. Occurs when the bulk of the coolant is below boiling, but the coolant adjacent to an extremely hot spot boils away from it)

Water does in fact have superior thermal conductivity, especially with a surfactant, compared to any coolant on the market, but it can't always reliably be kept in the system because of its relatively low boiling point.

The truth is, an engine would be more efficient without a cooling system. The idea of a gasoline engine in the first place is to extract energy from a liquid fuel in the form of heat, then convert that heat to mechanical power. Roughly 33% of the energy released from the fuel escapes through the exhaust system, and another 33% is wasted in heating up the cooling system. Being made of metal, there are practical limits to how hot the assembly can be allowed to get, so we're stuck with what we have.

Running the engine colder isn't necessarily better, and the fact that coolants allow an engine to run a little hotter while staying in control of its temperature is normally a good thing. The Japanese conglomerate, Kyocera, built an experimental all ceramic engine with no cooling system. It was noisey, very difficult to be anywhere close to, and had to be lubed with dry moly compounds. It also had to be a semi-diesel because the fuel would otherwise be ignited before it got to the combustion chamber. They didn't solve all the problems, but they proved the concept; it was very efficient.

Your bike is OK at any temperature that isn't so high that it interferes with lubrication, fuel control, or the integrity of the metal parts, and at which the cooling system can continue to operate correctly.

ok thanx everyone! very very helpful!

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