Overheating engine: Why it happens and what to do when it happens.

Overheating engine: Why it happens and what to do when it happens.

Overheating engines can and do happen, and the damage can be permanent if the right precautions and actions aren’t taken. Engines that run too hot can cause damage and ruin your journey.

Vag Spec Randburg is here to help you understand why engines overheat, plus, possible actions to take if your vehicle begins overheating while you’re driving.

What does the cooling system do?

The overall cooling system keeps a standard operating temperature for the engine by circulating coolant, or antifreeze, through the engine to the radiator, thus pulling heat away from the engine

What happens when the vehicle overheats?

Today’s engines are typically built to be durable, but when heat generated by a vehicle’s motor is well above the normal operating temperature, the devices made to cool this heat distribution may begin to fail, potentially causing permanent damage to not only the engine, but also the gaskets, hoses and seals that are designed to keep the engine running.

There are a variety of reasons that a vehicle can overheat, such as cooling system leaks, blocked hoses from corrosion and mineral deposits, radiator issues or broken water pumps. Regular inspections may help avoid overheating issues down the road.

What to do when your vehicle overheats?

If you’re on the road and the dashboard warning lights come on, you notice a strange smell coming from the engine, see smoke or feel your car isn’t driving as it should, follow these precautions for your vehicle.


  1. Pull over and assess the situation

As soon as you notice an issue with your vehicle, the next course of action is to pull off the road to a safe and clear area and turn off the vehicle. If the vehicle is overheating, continuing to drive with a potentially damaged engine may cause permanent damage.

  1. Keep moving only when necessary

If there is a situation where you are not able to come to a complete stop in a safe and clear area, keeping the vehicle slowly moving may still allow a constant airflow around the motor to help aid in natural cooling. Leaving your car at rest with the engine running may worsen the problem, which can quickly produce additional and unwanted heat.

  1. Turn on the heat

Yes, that’s right. When the vehicle is still in motion, turning off the air conditioning and increasing the heat to high may help to pull additional heat away from the engine.

  1. Open all windows

The goal is to release as much heat as possible. Rolling down and opening as many windows as possible is another way to allow heat to flow out of the vehicle.

  1. Call for assistance

The number-one option at this point is to call for service or roadside assistance


Do not try to open the hood of your car until the vehicle has cooled down.

Once the vehicle is at a complete stop and turned off, do not lift the hood. Depending on how long the vehicle has been running, the coolant in the vehicle could be increasing in temperature to an extremely hot level, and essentially pressurizing in the cooling system itself. Only once the vehicle has completely cooled down will it be suitable to attempt to open the hood. The vehicle should be allowed to cool down naturally before opening the hood.

To confirm that the vehicle has appropriately cooled down, monitor the temperature gauge in your vehicle as it moves from HOT to COOL, which may take upwards of 30 minutes. Depending upon the vehicle you drive, the temperature gauge may only be functional when the ignition is in the “accessory” or “on” position. During this step, it’s important to not start the engine, and in this situation, only activate the ignition to the “on” position to read the temperature gauge.

Common reasons for overheating engines.

There are a variety of reasons why a vehicle’s engine can overheat. Certain examples may be quicker fixes, such as refilling your antifreeze, but other issues may be more permanent if not properly taken care of by a professional.

Below are common factors that can cause a car to overheat:


1.To little or no coolant

Driving without proper levels of coolant/antifreeze may cause a coolant system failure. If coolant levels are lower than the manufacturer’s recommendation, refill or top off the levels with new coolant/antifreeze. When adding new coolant to an empty reservoir use only a 50/50 mix of antifreeze/coolant and water. If you are unsure where the coolant reservoir tank is located, or the proper method for refilling it, refer to your vehicle owner’s manual.

Coolant low warning

2. Cooling System Leaks

An empty coolant reservoir tank could be caused by a potential leak. Leaks in the coolant can often be identified by spots or puddles on the ground.

Be aware that coolant will have a sweet smell and may be green or pink in colour depending on the type of coolant being used.


3. A broken water pump

The water pump’s job is to circulate the coolant throughout the engine. If the coolant is dirty or has too much build-up, it can stop the coolant from moving through the pump, which can lead to an overheating situation.

4. Radiator Issue

Radiators and their fans help to reduce heat from the engine by decreasing coolant temperatures. Issues with the fans may reduce the capability of the radiator to remove heat, which will cause unnatural temperature increases.

 5. Oil to low

Outside of lubricating the engine’s parts, a vehicle’s motor oil helps control overall temperatures. Low oil levels may increase engine temperatures.

6. Thermostat failure

Like the thermostat in a home, the thermostat in a vehicle is needed to regulate engine temperatures. A thermostat failure may cause harm to the engine by not allowing the coolant to flow as intended by the vehicle manufacturer.

7. Issues with the belts and pipes

If coolant hoses are leaking, blocked or ruptured, or if the belts are worn out or frayed, their purpose of maintaining air and coolant flow to and from the engine and related systems will be limited and may lead to unexpected engine damage.

8. Heater core is plugged up

Coolant flow may be compromised if the engine’s heat exchanger unit is clogged or blocked, which can cause overheating in a vehicle’s engine.

Tips to prevent your car from overheating.

Remembering a few quick tips as you drive can help to alleviate permanent engine damage down the road.

  • Check your vehicle’s coolant levels on a consistent basis
  • Store an extra bottle of new antifreeze and a gallon of water in your trunk
  • Monitor your car’s thermostat as you’re driving
  • Do not overuse the car’s air conditioning on extremely hot days
  • Help cool the engine by running the heat at the first sign of overheating
  • Refer to the vehicle owner’s manual to stay up-to-date on coolant service flushes


An overheating engine is a sign of a serious issue. Regular maintenance checks will help identify problems early on, before causing permanent damage to your vehicle. If you have questions regarding your coolant and cooling systems, we’re available to help you here at Vag Spec Randburg.



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