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MG Midget and Sprite Technical - Coolant question
midget Mk III
Working my through overhauling my car, I came across ( I think in practical classics) adverts for waterless coolants. When I replace my coolant ( its fine presently) I am considering it but have never used them before- so....good idea or pants idea?
any opinions gratefully received!
|I seem to recall their boiling point corresponds with that of propylene glycol. Because of its lower thermal capacity, an engine using this coolant will run a few degrees hotter.|
|I thought various things I had read about it said it runs cooler, has a higher boiling point than water/glycol mix, runs at lower pressure and doesn't cause corrosion. However its very expensive especially to use the first time as you have to buy the coolant and a flushing mixture to purge all the water out of the system. You also need enough spare to carry around if you get a leak as you cant mix water with it. |
|Standard cars are designed carefully to run at the optimum temperature; running too cool robs you of power and is inefficient. If your car is running hotter than it should, fix the cause not pay extra for a workaround. You can tell I'm not a fan of the idea (perhaps 'marketing concept' is a better description).|
|I have used evans coolant in my 1500 but not used it on road yet so cant tell you if it makes a difference yet.It was given to me by a friend who used it in his aircraft and had it left when he stopped flying don't think i would have bought it as rather expensive.|
|mark (1977 1500 Midget) Preston Lancs|
|I've run 4-LIFE in various classics and brand new cars for over twenty years, as I learnt on this BBS it's not for ropy engines and coolant systems|
if you want more details I can post them
|Waterless coolant is usually Propylene Glycol. |
Propylene Glycol has a lower specific heat capacity than water- for every joule of energy imparted, its temperature increases more than water.
The upshot is that if your old water-based coolant could absorb all your engine's waste heat and maintain a temperature of 88C, then an equal volume of Propylene Glycol doing the same job will run at a higher temperature (about 95C).
Your radiator will appear more efficient because of the higher temperature difference between the coolant and the surrounding air. To the radiator, raising coolant temperature by 7C is the same as dropping ambient air temperatures by 7C.
A hotter engine is theoretically more efficient. The hotter the block, the lower the temperature differential between the block and the combustion chamber, the less energy the block will absorb. I'm not sure it's a huge factor on our wheezy little engines.
The boiling point of water is 121C at the 15psi your average pressurised coolant system runs at (100C if the pressure cap lets go). An engine with an 88C thermostat is running 33C below its boiling point, or, if the system should become unpressurised, 12C below boiling point.
The boiling point of Proplylene Glycol is 188C unpressurised. Your glycol cooling system running at 95C is 93C below its boiling point, without any system pressure.
For my Mini, waterless coolant makes sense. A Mini's radiator is barely adequate and fitting a larger one is problematic, so the increased coolant temperature makes the old radiator work better. A hotter than specified engine isn't an issue when the entire engine is made of cast iron. Eliminating the need for a pressurised system extends the life of aged and fragile plastic reservoirs, rubber hoses, and generally shonky BL workmanship.
On a Spridget, however, it would be a harder decision. You've got a decent radiator, and access to hoses etc is much easier. The cost of converting a wet engine is also much higher than if you're starting with a brand new, never-used dry engine.
Just my 2c. Actually more like $280.25
|more important than what kind of coolant is used: what additives are included to protect against corrosion?|
Most modern coolants are designed for aluminum radiators and engines, so they don't have the stuff that is needed by cast iron engines and copper radiators. I stick with the old fashioned coolant to make sure to best protect the inside of the system.
|We have started supplying Water Wetter due to popular demand by our customers.|
A lot of the competition guys are using Water Wetter and water, no other additives at all and continue to do so with clean and efficient cooling systems.
|Peter what about as an antifreeze on a road car|
|Nigel, water wetter is not an antifreeze, so for a road use car you will also need to keep using anti freeze to protect against splitting the block or radiator below freezing.|
What Water Wetter does do is help struggling cooling systems to work better.
The 1275 cooling system is quite capable for all but the most hot (90F ~ 100F+) use, so a healthy one doesn't need it.
Race cars don't use antifreeze, and need as much cooling as they can get (and they'd like to run the smallest radiator they can get away with), so they love the stuff.
Also, minis have very small margin in their cooling system, so they also love it.
|cheers Norm - those were my points that Water Wetter isn't an antifreeze and that track and road use are different things|
I tried the Millers brand in one of my cars once rather than replace the fresh coolant/antifreeze
as Peter has just started to stock it due to popular demand by his customers so obviously didn't stock it before I don't think it'll hurt his sales if I put it's effect as regards the temperature appears, from what little I read previously about it, to be a matter, like many of these things are, more of belief bit like me using Slick-50
|Key parameter is thermal conductivity- of water is much higher than organics.|
This thread was discussed between 11/01/2013 and 17/01/2013
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