Waterless coolants

I had a vehicle with an inherent borderline cooling system & found this to be quite interesting:

"The specific heat capacity of ethylene glycol–based water solutions is less than that of pure water; in a 50 percent solution, ethylene glycol’s specific heat capacity compared with pure water is decreased at least 20 percent at 36 degrees and about 17 percent at 200 degrees. Propylene glycol, another common coolant, has an even lower specific heat. Assuming a 100-gpm (gallons/minute) coolant flow rate and an energy loss through the coolant system of 189.5 hp, the water temperature increase would be 10 degrees, the ethylene glycol water mix would gain 20 degrees, and propylene glycol would gain 33.3 degrees.

Compensating for the reduced heat capacity of coolant/water mixes would require circulating more fluid through the system. Assuming a fixed amount of circulating fluid and radiator capacity, running 100 percent water would be the most efficient coolant in terms of its ability to conduct heat with minimal temperature rise. In other words, of all common liquids, water requires the most heat energy to change its temperature.

However, there are also differences in the vapor point of the three different coolants. Ethylene glycol and propylene glycol have higher vapor points and therefore can absorb heat at higher temperatures without boiling. Yet even with its lower vapor point, water still carries more heat per unit.

Don’t forget that the coolant is just one part of the total cooling-system “team.” You can raise water’s effective vapor point by using a higher-pressure radiator cap. For every pound of increased system pressure, water’s boiling point goes up by 3 degrees. Higher boiling points also reduce evaporation losses, water-pump cavitation, and heat-soak–induced after-boil. You can get away with a higher system pressure by using a quality aluminum radiator that’s rated for higher pressure than is a brass/copper radiator. Aluminum radiators can take more pressure because their tensile strength is greater than brass—this lets an aluminum unit use tubes with larger cross sections an thinner walls. A larger tube also has more wall-surface area, resulting in improved heat transfer.

Bottom line: A large-tube aluminum radiator filled with pure water and using at least a 20-psi cap is by far the best heat-transfer setup, provided the vehicle is not subject to freezing conditions. Be sure to add a corrosion inhibitor when running pure water."

It remarks in those links that a lot of race tracks ban it because of its slipperyness if the coolant gets on the track.

As you are supposed to put it a dry engine and not add water what happens if you get a leak in the middle of nowhere and havent got any of it to top up with. Would be more trouble than its worth and as said in the tests the motor could actually run hotter when using it Must be other cheaper solutions

Such as Redline Water Wetter!

Another retired Mechanic's observation, if you are like the rest of us, you probably have restricted air flow from a bullbar, winch, spotties, fly mesh, a/c condenser full of bugs; and a temperature gauge that probably works. Our set up as describes, doesn't appear to increase temperature when pulling our 4 tonne over the mountains but I bet it does. A better quality gauge would let us know and as long as the coolant keeps below the pressurized boiling point, all would be well.

Athol, as an aside, it has been proven that some coolants will in fact increase a Stray Current situation.

ARE Stray Current Article

The practice of lifting the bonnet at the rear can work if there is some sort of restriction to the air flow OUT of the engine bay. I have seen some sump guards cause overheating of both the engine coolant and the engine oil, just because a sump guard interfered with the normal flow of air.
Always consider the exposed engine sump to be part of the cooling system.
I recall that there were a number of Ford Falcon's practiced at Bathurst back about 1970 with the rear edge of their bonnets lifted about 30mm, following their final practice session, at the drivers meeting, it was made very clear to them that any car that was still in this configuration for the race would be black flagged for a mechanical infringement. There were several cars that had overheating issues during the race that they could have sorted earlier had they done their homework better.

Lifting the front of the bonnet is not only illegal but dangerous, as you are then relying solely on the secondary catch, which is only designed as a back up for short term use in an emergency.
Regards
Athol

When I was travelling and it got pretty hot I removed the plastic inner guards and it allowed better air flow through under the bonnet.

I used to have same problem with year model 85 diesel cruiser ute due to sealing of bonnet to prevent engine noise [ earlier utes had a fluted bonnet ] and with the narrow bonnet/mudguard design air flow was compromised , I made up 3mm spacers and put them between bonnet and hinges , it was enough to allow improved air flow and the temperature dropped substantially , and if you are worried , they could be removed in the cooler weather , also this overheating caused batteries to cook as the battery was in top rear left of engine bay , later models had an air vent installed in top rear of left mudguard which helped the batteries a little , At the same I had an 86 turbo cruiser wagon which never looked like heating up due to different bonnet/ mudguard design which allowed better air flow
All the best
Mick

On the matter of flushing and replacement of coolant.

All the modern long life coolants will claim very long drain periods ..... but regardless it is wise to drain flush and refill every 2 years every 3 at the outside.

On the matter of flushing chemicals ........ unless you have a badly contaminated cooling system, these agressive chemicals are un-necessary avoid them like the plague.

A hose flush followed by a couple of system fills with with clean tap water followed by short drives is all that is required.

Remember ...... in most modern vehicles it is very hard .... almost impossible to completely drain a cooling system.

So you flushing methods must reflect this.

ALSO, when adding coolant concentrate after a clean water flush ...... add concentrate bassed on the published coolant capacity,....... then top up with demineralised water. ....... if you mix coolant before adding it to the cooling system, the remaining water will dilute it.

Being a little over concentrated is no problem.

Another thaught ....... if it is an older vehicle and it has not been drained and properly flushed it is very likely it has an older generation coolant or a mixture of coolants ...... which although compatable will not be as effective as a complete fill of modern coolant.

cheers