Skip to content
Home » What causes a car to overheat?

What causes a car to overheat?

    What causes a car to overheat

    While driving the car, you suddenly saw the fumes coming out of the hood or the engine temperature gauge rising to a ‘red’ sign. This is surely not a pleasant situation to be in. It is a sign that your engine has overheated. Another sign of engine overheating can be a smell coming from the engine area. But, what causes a car to overheat? 

    Overheating of the engine is majorly due to a failed cooling system. The cooling system pushes the heat out of the car, but with its failure, the engine gets overheated. However, other reasons can also result in overheating, which includes radiator issue, defective belts, low motor oil, failed water pump, thermostat stuck closed, etc. 

    Let’s get to know in detail the reasons that cause a car to overheat. 

    What are the signs of an overheating engine? 

    If you see any of the signs in your car, your engine is overheating, and you need to look for its cause and get it treated immediately. 

    • Under the hood of the car, there is steam coming out that can resemble smoke.
    • A temperature indicator on your dashboard that reaches “H” or the red zone. Consult your owner’s manual for specific engine temperature gauge symbols.
    • The engine area is emitting a peculiar odor.

    What causes a car to overheat?

    An engine has an optimal operating temperature for efficiency. The temperature range is between 195 and 220 degrees Fahrenheit, and surpassing that temperature might have disastrous effects. So, if you find your engine to be overheating, these can be possible causes:

    1) Low or Contaminated Coolant

    The liquid that travels throughout the cooling system is coolant or antifreeze. If it is low, a pocket of air known as an “airlock” can form at the engine’s highest point and prevent the coolant from circulating. When this occurs, the coolant temperature continues to rise, inevitably resulting in a cloud of steam emanating from the engine compartment.

    Additionally, if the coolant has pollutants, it will not function as well and may not absorb as much heat, which will result in the car overheating. 

    2) Damaged Radiator

    The coolant loses its temperature when it passes through the radiator. The coolant circulates via the radiator’s tubes. Attached to these tubes are fins that collect the heat from the liquid, while air passing over the radiator removes the heat. If the radiator has sustained physical damage in an accident, it may be unable to perform this function as efficiently.

    In addition, the radiator cap is meant to maintain pressure in the cooling system. If the cap is destroyed, the coolant may boil off and depart the system without being cooled adequately.

    3) Damage to Radiator Fan

    The fan in the radiator pulls air from outside the engine bay across the radiator to cool the hot fluid more quickly. Even while you’re stopped, if your radiator fan isn’t working, it might cause your car to overheat. It doesn’t matter if you have an electric fan or a mechanical fan with a clutch.

    4) Failure of Water Pump

    An important part of the cooling system is water pumping. The water pump moves the coolant from the radiator to the cooling system, where it absorbs heat from the engine. Coolant returns to the engine after the radiator removes the heat from the coolant, and the cycle begins again. As a result, a water pump failure, such as a leak, could result in an engine overheating.

    Other typical indications of a failed water pump are coolant leaks under the car’s front bumper and steam emanating from the radiator.

    5) Low Motor Oil

    By reducing friction, motor oil helps to regulate the temperature of your car’s engine. So, if your vehicle’s oil level is low, potentially due to an oil leak, the engine may overheat.

    Oil lubricates engine components and ensures their smooth movement. Lack of lubrication results in friction, which generates excessive heat and may result in engine failure.

    6) Faulty Hoses

    Belts and hoses are necessary for the engine’s cooling, air conditioning, and charging systems. Belts are used to transfer power from the engine’s front to accessories like the air conditioner, charging system, and fans. The Radiator and heater hoses transport coolant from the engine, radiator, and heater core to and from the radiator and heater core.

    If the hoses are damaged, fractured, loose, or clogged, the coolant may leak, or they may impede the flow of coolant.

    7) Malfunctioned Thermostat

    When it comes to car parts, the thermostat is no exception. A malfunctioning thermostat can have serious consequences for the engine, as it controls the flow of coolant and helps prevent overheating.

    In addition to overheating, a faulty thermostat may exhibit unpredictable temperature variations and/or coolant leaks beneath the car.

    8) Improper coolant concentration

    A typical coolant combination consists of 50% coolant and 50% distilled water. A higher ratio of water to coolant can help prevent freezing but can also be damaging because coolant isn’t very good at transmitting heat on its own. Overheating can occur if the coolant mixture is too concentrated.

    So your car can have any of these issues, which result in car overheating. So check with the mechanic as soon as possible and get it treated. 

    What causes a car to overheat while idling?

    A clogged radiator, a damaged radiator fan, low or no coolant, a weak water pump, or a defective thermostat are all possible causes of engine overheating while the vehicle is idling.

    What causes a car to overheat when the AC is on?

    If your car is overheating when the AC is on, then the causes can be many. A failed water pump, a bad coolant temperature sensor, a clogged radiator, clogged condenser fins, a faulty cooling fan motor, or a faulty ac compressor clutch are all possible causes of car overheating when the AC is on. 

    What to do if your vehicle begins overheating?

    If you experience a vehicle overheating while driving, then you should do the following things immediately: 

    • Turn off the AC to reduce engine stress. Turn up the heat. This can keep the engine from overheating until you can pull over safely.
    • Turn off the automobile. Wait 15 minutes before starting the engine. As the engine cools, the temperature gauge should normalize.
    • A fast coolant top-off can preserve your engine from overheating until you can fix it. If a coolant hose is clogged or a radiator fan or water pump is broken, this won’t help.
    • If your automobile isn’t being towed, restart it and drive to the shop. While driving, watch the temperature gauge. If it increases again, stops and cool the engine.

    How to prevent a car from overheating?

    The easiest approach to preventing your car’s engine from overheating is to have regular coolant flushes, and exchanges performed and to keep up with radiator maintenance as the vehicle manufacturer recommends.

    Routine checks can also aid in identifying and resolving any radiator or engine problems before they deteriorate.

    Bottom Line

    So these were all the main reasons what causes a car to overheat. It can be an issue in the thermostat, radiator, water pump, low coolant, low motor oil, and some other reasons. If you encounter overheating, try to cool off the car, get it to the mechanic as soon as possible, and get the issue treated. 

    We hope this article was helpful & informative. Please leave your valuable thoughts & suggestions in the comments below!

    Thank you for reading!

    More Amazing Articles for You

    Why Aren’t There Any Four-Door Convertibles Out There?

    Why Does the Brake Pedal Become Less Sensitive?