Y'know, our old mate Starfire - who ran that old 3/1 over on the West Coast of New Zealand as his sole generator for maybe seven or eight years - said leave some oil floating on top of the coolant water to radically reduce evaporative loss.
It wouldn't surprise me if it left an oily residue on the tank surface?
Makes sense that the layer of oil will achieve that, but I see two potential problems with that:
At work we have various fairly large lathes and turning centres with water coolant systems. Over time the mineral lubricating oil used on slideways and some leaks on the machines forms a oil layer on top of the water. The moment the surface is sealed off to "breathe", the water quickly goes bad. AND STINKS!!! There are nowadays anti-bacterial additives in the soluble oils to combat this, but the best fix is to skim the oil off every now and then with a vacuum cleaner.
It would probably not make a massive difference, but there will be loss of cooling capacity if the water cannot evaporate. I think I mentioned this earlier - my '42 Fairbanks-Morse 8Hp engine is hopper cooled, and it is required for the water to boil to achieve proper cooling. Something like ant-boil / anti-freeze in the water will thus cause the engine to overheat. A Lister can of course never get THAT hot!
Or you could do as I have done and use a copper hot water cylinder?
Oh yes! I love the look of the copper cylinders! But I can't find one to save my life... First prize for me would be a brass or copper radiator... But for now I'm making the best of the old grease drum
For many years I ran a mixture of engine oil and detergent in my Vehicles cooling system.
I was basically trying to make soluble oil and seemed to achieve that.
I worked. Never had any rust or corrosion in that cast iron engine. <<SNIP>>
Dissolved the oil with the detergent to make a white mix and put it in with a new radiator. Never had a cooling problem in the 3.5 years I had the car and never saw a speck of rust or scale. and I looked. Frequently.
Interesting idea... I'm busy exchanging e-mails with one of our local oil suppliers and it seems like they have something synthetic that will do the job BUT at a price. Pity communication is not too good so I can't tell you much more now - I'll probably have to go there when I get time.
From what I did see the oil seemed to permeate the scale that was left and neutralize it. Bit like fish oil. Had some rust in that car when I got it and I blew fish oil into it with an old spray gun turned way up so the oil was like a fog and that rust never moved. I pointed it out to the guy I sold the car to who was very pleased I had done it as he always did it to his cars too. <<SNIP>>
So I've never worked with fish oil before and inSTINCtively (excuse the pun) I'm thinking that your car now smells like dead fish??
Why fish oil? Does it go dry or sticky - unlike mineral oil?
How about using central heating inhibitor in a car cooling system? That's designed to prevent rust/scale, on dissimilar metals too (copper pipe/steel radiators/brass valves). I haven't looked at it myself, it rarely gets hot enough in the UK to bother a modern car's cooling system.
I'll never try out anything other than the OEM coolant additives in my car. It works well in our extremes of cold winters and hot summers, and the cost is not that high either. The coolant has a number of jobs to to, and if you miss one the repair bill could be ugly. (Anti-boil / anti-freeze / anti-corrosion + Water pump lube)
I recently changed the coolant on my 4.0 V6 Toyota. First coolant service was scheduled for 170,000 kms. The slow service frequency gives me one less thing to worry about. I like that
More time to tinker with my toys.