LIQUID ENGINEERING AT WORK

A brief look at extended life coolants and why they are an engine’s best friend

- Andy Miller

There is nothing sophisticated about coolant, just mix a bit of antifreeze with some water and it’s good to go, right? Well, the answer to that depends entirely on how long you expect your engine to last and how much you want to spend repairing it because coolant does a lot more than simply move heat from the engine to the radiator. To those who design cooling systems, the coolant they depend on is a product of liquid engineering and it’s anything but unsophisticated.

In addition to protecting an engine from heat and cold, a properly formulated coolant serves as a carrier for additives such as pH stabilisers, anti-foaming agents, and protection agents for rubber and plastic components. It also contains additives that inhibit corrosion within the heat transfer system that typically includes components made of copper, brass, steel, cast iron, aluminium and solder. Without that protection, corrosion can block the narrow spaces in a radiator, which can lead to overheating of the coolant causing damage to water pumps, oil coolers, cylinder heads and gaskets.

A less obvious feature of coolant is protection against cavitation and cylinder pitting, particularly in wet-cylinder diesel engines where the sleeve that contains the piston comes into direct contact with the coolant. While this design allows more efficient heat transfer, it also transfers a lot of vibration and, movement from the pistons to the cylinder sleeve, and through the sleeve to the coolant which can cause cavitation.