All engines require cooling. Most of the cooling in car engines is done by water, mixed with coolant, circulating around the engine until it is piped into the radiator. Inside the radiator the water is distributed over a very large surface area. This makes it possible for the water to be quickly cooled by the flow of air in front of the car.
A large surface area is critical for the rapid transfer of heat between two different materials. Imagine a cup of water outside in the sun. Even on an incredibly hot day there is very little evaporation from the cup, this is because the area the sun is trying to heat is very small, maybe only 7 or 8 centimetres across. But if one were to pour the contents of the cup onto concrete the surface area would be extremely large and the water would quickly be gone. The same principle applies inside the radiator, except the end result here is not the evaporation of heat but the cooling of the water by the removal of heat.
But this is not enough on its own. The engine needs something to get into its very core and remove heat from around the combustion chambers. This is where oil comes in to play. Even casual motorists know how important the oil pressure gauge is on their dashboard. It’s connected to the oil pressure sensor and is the first warning to the driver that there is a problem with the oil system. But few realise how the engine is also cooled by the oil system. When the oil is pumped around the engine it absorbs excess heat. Because it covers all the moving parts it has a very large surface area to work with. Then once the oil is pumped into the oil pan it is cooled by the air flow underneath the engine as the car motors forwards.
Both systems are vital to keep the car on the road and both should be checked and maintained ona regular basis.
