The misunderstanding of the purpose of the liquid coolant is rooted in the fact that the industry monitors the coolant temperature alone and not in conjunction with the metal surface temperature of the combustion chamber in the cylinder head. The proper method to determine if the engine is in thermal distress is to compare the liquid temperature to the metal surface temperature of the cylinder head. Only then would the picture be clear. If the metal surface temperature is climbing and the liquid reading is not keeping up then the engine is on the verge of metal overheating though the coolant may be far from boiling.
As the liquid’s temperature increases its storage ability or in other words, its potential to absorb more heat is diminished. When this occurs, the liquid temperature as read on a coolant gauge may appear to be stable, albeit at an elevated temperature, but the metal surface temperature of the combustion chamber and around the exhaust valve skyrockets. This can lead to detonation (ping) and engine failure from a cracked cylinder head. Engines that employ an aluminium cylinder head are extremely sensitive to this since the steel valve seats are pressed into the head as an insert. Numerous or prolonged excursions to extreme metal temperatures along with thermal cycling can cause the seat to fall out. With rare exception this is met with total destruction of the engine as the piston collides with the valve and the steel seat. In almost every case the engine never overheated according to the liquid temperature but the metal surfaces did. Thus, the most effective liquid coolant is one that has the ability to absorb a high amount of heat before boiling which will result in the coolest metal temperatures in the cylinder head. When the liquid can abstain from boiling and continue to absorb heat there will be more thermal transfer from the cylinder head.
When discussing a cooling system it must be noted that though the coolant is also employed to remove heat from the engine block and cylinder walls, its most challenging assignment is to control the temperature of the combustion chamber and exhaust valve area.
Evans Waterless Engine Coolant does not boil until over 190 degrees C virtually eliminating any chance of overheating in the radiator. This high boiling point is responsible for a drastic drop in the metal surface temperature of the combustion chamber in the cylinder head over traditional coolant. This benefit is apparent not only when the engine is running but also during heat soak. This is defined as the period when a hot engine is shut off and since there is no liquid movement through the radiator the critical components rise in temperature. Due to the Evans product refraining from boiling more heat transfer occurs.
For more information visit www.evanscoolants.com.au