The majority of cars on our roads today are water-cooled, save for a few old school jalopies which are air-cooled. Even electric vehicles use water-based coolants to prevent the battery pack from overheating. Water or water mixed with chemical coolant keeps the engine(ICE) at the desired temperature, commonly known as optimum temperature. This is usually indicated on the dashboard by the temperature gauge, which the driver should always keep eye on. However, just as any other system that is prone to failure, the cooling system which comprises different parts is no exception. Understanding the engine cooling system will help you make sober decisions that will keep your engine healthy and money in your wallet.
Since the engine operates at optimum temperature, a thermostat regulates that temperature, which is normally 80-90 degrees in most cars. Located at the junction of the coolant hose and engine, it operates by closing and opening, allowing coolant to flow through once the optimum temperature is achieved. It however remains closed before this, enabling the coolant to heat faster. A thermostat can fail in two ways, by either remaining open or closed. While both cases aren’t healthy for the engine, the worst case is remaining closed. This means that coolant does not circulate even after the engine has attained optimum temperature, resulting in overheating. In the case of the thermostat remaining open, the engine is cooling all the time even when it’s supposed to warm up and attain optimum operating temperature. This translates to inefficiency in terms of power delivery and higher fuel consumption as the engine tries to compensate for the unattained optimum temperature.
Carbon or soot build-up inside the engine is inevitable due to the mentioned inefficiencies. Always make sure your engine has a functional thermostat. Removing a thermostat completely after a car overheat isn’t a solution but a knee-jerk reaction. It will only give a false sense of hope that all is well while carbon builds up in the engine, as you cough out more at the pump. Another component that can ruin your engine is a faulty water pump. As the name suggests, this component pumps water(coolant) for efficient circulation around the engine. A failed water pump means that the hot coolant doesn’t circulate to the radiator, whose main purpose is cooling it before it recirculates. This leads to overheating, which if not addressed on time can cause irreversible damage.
Whereas some leaks are external and visible, others like a blown head gasket are not. Separating the oil and coolant passages, the head gasket gets old with time or due to overheating brought about by various factors. This creates an internal leak where coolant mixes with oil, affecting both lubrication and cooling massively. Warping of the cylinder head can be a result of a blown gasket and overheating. Always be on the lookout for the color changes in the oil and coolant reservoir.
External leaks include severed hoses, cracked blocks, leaking radiators, and faulty radiator caps. Since the cooling system is pressurized, a radiator cap plays a key role in regulating the amount of pressure in the system by releasing excess pressure. A faulty cap can leak, or fail to release the pressure accordingly. Either way, the engine is in danger of overheating due to inconsistency in pressure. Although not all modern cars have a radiator cap, pay close attention to it if your car has one. As engine block gets old, tear and wear due to heat and chemicals can cause cracks to form. The pressurized coolant will escape through these cracks gradually and can be difficult to detect as opposed to leaking hoses and radiators. Bottom line, with low coolant the engine will overheat. Always take note of leaking coolant on the ground at your usual parking spot.
— Johnson Škoda Guy🐦 (@TDIplug) September 2, 2022
In conclusion, whenever you detect abnormal temperature readings on the dashboard, make haste to diagnose the cause. Temperatures over 90 degrees Celsius would suggest overheating, while lower than 80 degrees Celsius(once the car has covered a substantial distance) means unattained optimum temperature. While overheating can also be caused by low or no coolant, a faulty coolant temperature sensor can also be the cause. There are different components that can fail including a blocked radiator, brought about by rust or additives. Always get a proper diagnosis before replacing parts haphazardly.