Evens waterless coolant

[Tranona]

I think he is referring to the Evans product in the original post which cannot be mixed with water and makes much more extravagant claims.

Still don't see it is necessary for use in small marine diesels.

 

[Marsupial]

If you care to look at the specific heat (SH) of liquids you will find that water is pretty near the top, which makes it a very good coolant. Furthermore a property of water is that its SH increases as the water gets hotter - therefore the hotter it gets the better it works as a coolant.

The problem with this is that pure water is very aggressive and corrosive, but mixing it with a corrosion inhibitor reduces its effectiveness as a coolant (SH reduces) and it looses some of its coolant ability.

Modern engines (automotive) take this into account and have larger radiators at higher pressures, but old ones didn't which is why on some cars you had to remove antifreeze in the summer - their cooling systems were "on the edge" most of the time so the 25 - 30% drop is Specific Heat was critical even in an English summer! They had thicker castings to compensate - strange but true.

At a first glance this water wetter stuff looks like snake oil, a couple of drops of soft soap will make water wetter - makes you think . . . .