You don’t want your car to overheat, and the cooling system prevents that. There are several parts within the system that work together to keep your engine running at a safe temperature. Let’s take a look under the hood.
Coolant and the Coolant Reservoir
The first components on the list are your coolant reservoir and the coolant it holds.
The reservoir is essentially a plastic container that holds excess coolant so the system can “breathe” as the coolant expands and contracts with temperature.
Oftentimes there will be a high and low mark on the reservoir, signifying the minimum acceptable amount of coolant, and the maximum before it will overflow as it heats up.
Near the top of the tank, or sometimes through the cap of the reservoir, the system will bleed air or coolant (if it’s overfilled) as necessary.
DO NOT OPEN THE COOLANT SYSTEM WHEN HOT
The operating temperature is between 160-220 degrees Fahrenheit, it can and will spray out and burn you.
Coolant is the fluid filling your cooling system. There are many kinds of coolant, verify at the parts store that the type you are buying is correct for your vehicle.
Sometimes coolant is sold concentrated, in which case you will need to dilute it with water as instructed on the label according to your environment.
So from the coolant reservoir, the next stop is the radiator.
Radiator and Cooling Fans
The radiator sits at the front of the engine bay, often tucked between cooling fans and the AC condenser.
Some radiators have a cap where you can also fill or verify the level of coolant WHEN THE ENGINE ISN’T HOT.
The radiator is an often aluminum series of pipes that the coolant can run through, with fins and holes allowing air to cross the surfaces of the pipes and lower the temperature of the coolant.
Cooling fans aid in air flow across the radiator when necessary, to keep optimal temperatures.
After leaving the radiator the next stop is the water pump.
Water Pump
The water pump is actually what forces the flow of the coolant through the cooling system. It is a small pump, driven by a belt or chain connected to the crankshaft. So when your engine spins, so does the pump.
The pump essentially pulls the colder coolant from the radiator and forces it through the engine coolant passages to cool off the engine.
The water pump is a fairly simple, yet incredibly important part of the engine. Without it working properly your engine can overheat in minutes.
Thermostat
The next piece of the system we will discuss is the thermostat.
Thermostats use springs and a wax which melts at a specified temperature. Usually 160-180 degrees F. Once the coolant inside the engine block heats to this level, the thermostats wax melts, allowing a spring to open it and flow coolant into the radiator.
When closed, coolant continues to circulate within the engine block to more quickly warm the engine up to operating temperature.
A stuck open thermostat will lead to poorer engine performance as it takes longer to heat to operating temp.
A stuck closed thermostat will overheat the engine, as it doesn’t allow the lower temperature coolant from the radiator to flow into the engine.
Hoses and Pipes
The coolant travels between all these parts through various hoses and pipes. Any of the hoses can leak given age or excessive temperatures, due to a part failure elsewhere in the system.
Pipes can be made of metals or plastic. Metal pipes rarely break, but O-rings at the ends can fail.
Plastic pipes are a common failure point due to the constant heating and cooling stressing the material.
Heater Core
The final part of the system we will touch on is the heater core. The heater core resides in your dash next to the blower motor.
Hot coolant from the engine block passes through it, then the blower motor forces air across the core (which is basically a mini radiator. This produces the heat out of your vents.
Accordingly, a telltale sign you are low on coolant is your heat not working.
Now you know more about how your engine stays cool, which is pretty gnarly dude.
If you have any further questions be sure to comment below or find us on Twitter @BowTiedGreaseMonkey