But too much can make it go the other way Molina and not work properly..
Extract from
http://www.gr8website2.com/calverst/CC114.htm
The coolant explained:
Water is the most common form of coolant used in car engines. It has excellent heat transfer properties in its liquid state and does an extremely good job when properly controlled. It does have one or two shortcomings though. The worst from a cooling point of view when not controlled is it?s very high surface tension - the thing that allows bugs to walk around on it without sinking.
This surface tension limits its ability to ?wet? the metal surfaces of the water jacket, forming a sort of barrier. Because of this, hot-spots can be caused - particularly around the combustion chambers where temperatures are highest. These hot-spots form vapour bubbles by boiling the water despite the fact that the bulk of the passing water is well below boiling point. The bubbles formed on the metal surfaces then act as an insulator around this area, greatly impeding heat transfer. This in turn reduces the cooling systems efficiency, thereby increasing the combustion chamber temperature.
The eventual result is component failure, the piston usually being the first to go, or maybe the spark plug, then the exhaust valve, inlet valve, and so on. The speed at which this can happen can be alarmingly quick, and is governed by the severity of the hot-spot and the dynamic loads on the engine (i.e. foot hard down = max. load = blisteringly quick melt down if there is a hot-spot present).
Anti-freeze is widely used as an additive to water in car cooling systems, and is indeed essential where freezing temperatures are to be experienced. It also raises the boiling point slightly, as well as providing some lubrication for the water pump seals and reduces the formation of rust on the iron surfaces. The reduction of corrosion helps prevent blockages in the radiator. It does not, however, increase the cooling capability of the system. Many people are under the false impression that adding more anti-freeze will solve over-heating problems - nothing could be further from the truth.
No more than is absolutely necessary to provide sufficient protection in the environment in which the car is used should be added. Follow the manufacturers instructions to the letter. Although as standard all road cars have a larger cooling capability than is required to allow for a fairly strong anti-freeze/water mix, bigger or more powerful (tuned) engines will soon render it inadequate.
Water, as previously mentioned, has amazing heat transfer properties, far better than almost any other liquid cooling medium within a vast majority of spheres. It is certainly superior to a mix of anti-freeze (usually glycol based) and water. In fact water has up to two and a half times greater thermal conductivity to, say, a glycol-type coolant given the same operating capacity. As the cooling system works by conductivity - from hot metal to a cooler liquid (as in the engine water jacket) then from hot liquid to cooler metal surfaces (as in the radiator), the coolants thermal conductivity is of ultra importance. Tests carried out by major motor manufacturers have concluded that the improvement of glycol?s thermal conductivity is practically directly proportional to the amount of water added to it. Just to illustrate this, a 50/50 water and glycol mix has about 70% of the thermal conductivity of water on it?s own.
To labour the point so that you are left in no doubt about this, other factors such as the viscosity of the coolant, and the convection coefficient of the coolant in a tube (a complex relationship between the thermal conductivity, viscosity, tube diameter - as in radiator core tube - and turbulent flow of the system) influence the effectiveness of the system. A 50/50 glycol/water mix has roughly four times the viscosity (thickness) of water alone and, as previously mentioned, about 70% of the thermal conductivity. A trial using these factors established that this mix had approximately 50% of the convection coefficient of water only.
Or to put it in English, water on it?s own as a coolant is capable of TWICE as much heat transfer as the 50/50 mix. Hopefully this has exploded the ?more anti-freeze will help? myth once and for all.
