Can a surfactant* ( in water in radiator ) noticeably cool engine, if water temprtre is just 70°C ?

As long as it doesn't foam and is not corrosive, at least it shouldn't hurt anything.

The physics are as follows: For optimum cooling, the system should be in turbulent flow in the radiator, the radiator should not be internally or externally fouled with anything, and there should be ample water and air flow.

( We've been through that crap about water circulating too quickly through the radiator to be cooled. Was always crap, is crap now, and will always be doofus physics.)

The surfactant may be able to help cleaned fouled surfaces. It might even cause an change in the effective Reynolds number. Since it reduces surface tension, it might even allow water to pass a little faster through a radiator core.

And last of all, if it is of the correct type, it can actually give a little lubrication to the water pump. (Block polyols can do this if chosen carefully).

Try it and report back.

I run a waterless coolant in my bike. Stuff works great. We run a surfactant in our Fire trucks, both in the cooling system and in the tanks. Keeps the systems clean and seals last a LOT longer. We use Basic H in the tanks and Water Wetter in the radiators.

| it shouldn't hurt anything. Can hurt buyer's wallet ( Water Wetter is retailed here @M$48 = US $12.63 ) & waste his time in draining out radiator etc.

| Try it and report back. I can try a cheaper brand ( TopOne, Coopel ) if they have no antifreeze. Most brands ( e.g. Abro, Bardahl ) sold here have antifreeze ( useless here ).

If a * can work in water 40-90ºC, then buildings' central heating systems can use * too. Is any * used in US / Canada 's central heating ?

In the USA, our central heating systems are not usually hot water exchange systems. They are often either gas fired with heat exchangers or electrical heating. I have never seen an instance where such a product might work here.

Now, in cooling towers chemicals such as surfactants ARE used incorporating antifoulant properties, antifoam, etc but the application is not quite the same.

If you just remember that to have best heat exchange from a water (or liquid) to air, the liquid should be in turbulent flow inside the exchanger and the surfaces should be clean. If neither of those issues is a problem, you are probably wasting your time with chemicals.

Thanks for reply.

| > | Try it and report back. | you are probably wasting your time with chemicals. No waste ; I've found & put a cheap ( M$3.70 for ½ litre ) brand into my Mitsubishi 4G15P engine's NipponDenso radiator, result is fantastic : cylinder head is much cooler, even before water ( entering cylinder head ) reaches 60°C.