Coolant is a liquid that lubricates your engine and protects it from corrosion. It is usually mixed 50/50 with water which is a better conductor of heat than coolant. The coolant raises the boiling point of water which allows the cooling system to be more pressurized and work more efficiently. Your engine is really a contained explosion device, that powers your car. The series of explosions heats up the engine and can eventually warp the metals inside if it gets too hot. The coolant therefore is very important to ensure your engine does not overheat or rust, and on top of that it also protects the engine from being damaged by the intense friction.
What Coolant Does
The coolant mixture is pumped around the engine by a water pump. The coolant passes through the engine, absorbing heat, and takes it to the radiator. From there, the fins of the radiator allow a lot of air to flow through the engine compartment which cools the coolant down. At lower speeds or idling, a radiator fan is usually active to assist the airflow into the engine compartment. The cooled solution is then sent circulating around the system again. A thermostat will regulate the flow of coolant to keep the engine at an optimum temperature (200℉, 95℃). When the car starts the thermostat will block the flow of coolant to allow the engine to heat up.
What Is A Cooling System Thermostat?
A thermostat regulates the amount of coolant flowing through an engine to maintain a certain temperature. The thermostat can usually be found, under the bonnet, between the engine and the radiator. When the car starts to run, the thermostat blocks all coolant, so the engine can quickly get up to an optimum temperature (200℉, 95℃). This temperature helps the car to run smoothly. If the engine temperature rose more gradually, the engine would wear out faster and there would be more toxic emissions.
As the engine gets hotter, a lot of the lubricating oil dries out. The heat will trigger mechanisms inside the thermostat, be they electrical or even wax-based. The thermostat opens the path for the coolant to run through the engine, cooling and lubricating it. The thermostat will then close again once the engine reaches its optimum temperature. If you’re interested in understanding better how the part works it’s worth buying one from a car parts store just to see it work as if by magic in a cup of boiling water.
Like all bits of a car, the thermostat can fail and unless you have an infrared heat gun lying around it can be hard to spot. The thermostat in extreme conditions can seize up. In hot conditions, this can mean the engine takes a long time to warm up so you release more pollutants. In cold conditions, it can cause your engine to overheat as it has no access to the coolant. In both cases, it is best to replace the thermostat as soon as possible to prevent damage to the engine.
Why coolant is important
The heat inside the engine is enough to warp the internal metals. Aside from being functional, the engine also needs to be efficient, which is why there is an optimum temperature. Water alone would boil quickly and evaporate to leave a cooling system full of hot moist air, something that would cause corrosion. The coolant mixture prevents this by having anti-corrosion properties and raising the boiling point of water. The pressure cap on the radiator also helps to maintain the water as a liquid by holding the system at a specific temperature. In cold weather, the coolant also prevents the water from freezing by lowering the melting point.
The coolant will need to be replaced eventually, as while the antifreeze doesn’t expire, the corrosion inhibitors do. Usually, this will be done during your scheduled services. The cooling system needs to be flushed and then the new coolant will be added. Multiple types of coolant may react badly together and clump together, clogging the system for an expensive repair.
A scheduled service can check the rest of the cooling system for any other issues. A lot of repairs for overheating can be solved by making sure your engine is working well. Ensuring your engine’s cooling system is working just before the summer heat can save you thousands in repair bills.