How Car Cooling Systems Work

In order to produce motion, car engines turn chemical energy into mechanical power. However, any mechanic will tell you that cars don’t do this all that efficiently. In fact, around 70 per cent of petrol is converted into heat instead of energy — certainly enough to cook your car parts if it wasn’t for the cooling system. It?s for this reason that the cooling system is so important. However, the cooling system isn’t just about dissipating heat — it also needs to ensure the engine remains at a consistent temperature (about 93 degrees Celsius) to optimise performance.

The basics of car cooling

At 93 degrees Celsius, the engine has the following benefits:

• The combustion chamber is hot enough to vaporise the fuel entirely, allowing for more efficient combustion and less emissions.
• The engine’s lubricating oil is thinner, so the engine parts are able to move more freely. This enables the engine to use less power.
• The metal parts will wear slower.

Most modern vehicles use liquid cooling systems, circulating fluid throughout the engine. The liquid absorbs the heat, cooling the engine, and then makes its way into the radiator.

Car cooling plumbing explained

Much of the plumbing in your car is there as part of the cooling system. It all starts at the pump, which delivers the fluid to the engine block before making its way around the cylinders through various engine passages. As the fluid leaves the engine, it passes by a thermostat which regulates the amount of water going into the radiator. If the fluid is cool enough, it makes its way straight back into the pump. If not, it is sent to the radiator where the heat is lost to the atmosphere and the cooled fluid is eventually sent back into the engine.

Using the right fluid

The fluid used to cool the engine needs to have a very low freezing point and a very high boiling point. Unfortunately, water freezes at too high a temperature to be effective for car engines. As a result, most cars use a mixture of water and ethylene glycol, more commonly referred to as ‘antifreeze’.

What causes overheating?

Overheating will occur when the cooling system’s capacity to absorb, transport and dissipate heat is compromised. As a result, many things need to be checked during your car service to ensure cooling is taking place correctly. Some of the reasons behind overheating could be:

• Low coolant level: If coolant levels are low, then there simply won’t be enough water running through the engine to cool it down. All service stations have watering cans on hand that allow you to add more water quickly and easily.
• Coolant leak: If the coolant is leaking, you’ll have another problem altogether. The coolant levels will start getting low and eventually run out completely; what’s more, you won’t be able to fix it simply by refilling. You’ll need to locate the source of the leak and have it fixed, and you may need to get a car service in order to achieve this.
• Poor heat conductivity inside the engine: This can occur due to an accumulation of deposits in the water jackets.
• A defective thermostat: If the thermostat is not working correctly, it won’t be able to properly regulate the flow of water through the radiator. This may result in overheated water being sent back into the pump.
• Poor airflow through the radiator: This will inhibit the radiator’s ability to release the heat from the coolant.
• Water Pump requires replacement as it is not circulating enough water volume.