On 31 October 2012, J P Birkbeck in Warwickshire, UK wrote:
"Driving a Y-type, Evans Waterless Coolant looks a very promising way of potentially overcoming the use of water in our cooling systems and avoids the use of anti-freeze, provides enhanced flow and can be reused. It's not cheap.... Experiences would be useful".

In couple of words, forget it. No go for a vintage car with marginal cooling capacity. For cooling it is similar to running 100% glycol and no water.

Specific heat of water = 1.00
Specific heat of 50/50 = 0.81
Specific heat of Evans = 0.68

Additionally, viscosity of Evans is about 4x that of 50/50 mix, and 10x that of plain water. This will reduce coolant flow rate about 20-25%, driving fluid temperature even higher.

To make this work without changing the coolant temperature you need 20% more fluid flow to make up for the reduction of specific heat number. You need an additional 25% increase in pumping capacity to make up the higher fluid viscosity. 1.20 x 1.25 = 1.50, meaning you need 50% increase in pumping capacity for the water pump, and the vintage car cooling system cannot do that. With boiling temperature of 369dF you don't need any pressure in the cooling system. Any claim of improved fuel economy comes only with higher operating temperature, and carburetors have a tough time with that, especially with modern fuel with 10% alcohol content.

Without increasing the pumping capacity you may expect 40dF increase in coolant temperature (or maybe more). Cylinder head temperature around the exhaust valve seats runs hundreds of degrees higher than the coolant temperature. Increasing the coolant temperature increases valve seat erosion. At the very minimum, the vintage engine would need hardened steel valve seats to resist erosion.

And the stuff will burn.
Flash point of Propylene Glycol is 130 C (266°F).
Flash point of Ethylene Glycol is 111°C (232°F)
At any temperature above the flash point it will produce a vapor than can explode (if ignited).

Autoignition temperature of Ethylene Glycol is 410°C (770°F).
Autoignition temperature of Propylene Glycol is 471°C (880°F).
If it is spilled on a hot exhaust manifold it will immediately vaporize. If the manifold temperature is above the autoignition temperature, it will immediately start a fire. If there is an engine fire with loss of coolant, the waterless coolant will provide LOTS of fuel for the fire.

It is also VERY slippery when spilled on tarmac. For these reasons many racing organizations prohibit the use of any glycol product in the cooling system.

Bottom line is, I say this stuff is a very bad idea for a vintage car.

On 29 September 2016, D M Tuffin, Warwickshire, UK wrote:
"I used Evans waterless coolant in a Subaru. .... I got a serious burn on my arm from one of the silicone pipes that I fitted, the temp of engine must of been in region of 150+. Engine had permanent rattle on startup afterwards too.
"I removed the waterless coolant, and did a little homemade experiment with the stuff, heated 2 bars of steel up and immersed one in water and one in Evans coolant, 10 secs later I removed the bars from each, the water bar was cold and the waterless coolant bar was still too hot to touch, the Evans coolant was also still warm a long time afterwards unlike the water.
"Water conducts heat away much faster, hence why it's been used since time began. I would never ever use waterless coolant again, a very expensive and painful mistake. I would also tell anyone thinking of using it because of overheating, Don't !! Just flush your system out well,and use good old water and antifreeze. Hot climates get a tropical core rad"