Car Engine Overheating Causes and Actions

An overheating engine is a sign of a problem with your vehicle’s coolant system. If your car overheats quickly, you should see a mechanic. If your car is running hot but not overheating, it’s a warning sign that there’s a problem, and you should have it inspected.

Car Engine Overheating: No one likes an engine failure in the middle of a drive. Engine heating can be one of the reasons for such failures. Overheating can happen to any vehicle and cause permanent damages if you don’t fix it immediately.

So, you must know all the causes of engine overheating to prevent it from happening. Here we will guide you on the reasons why car engine heating happens and how you can avoid it.

Why does your car engine overheat?

A car’s engine comprises many components. Each component complements others to perform the required function. If any complication happens to one part, it impacts the whole system.

For example, your car’s engine contains a cooling system. The cooling system is supposed to manage excessive heat generation. But if it stops functioning properly, it can lead to engine overheating. Similarly, there may be other reasons why your vehicle’s engine overheats.

Engine overheating may result due to the following reasons

Below are the major reasons for engine overheating.

1. Lack of coolant

A coolant is an antifreeze called ethylene glycol diluted with water. This solution freezes at a lower temperature than water. Thus, it serves as a better coolant than water in cold weather conditions.

The role of a coolant is to maintain a suitable temperature in the engine and save it from overheating. If the coolant doesn’t reach the radiator due to pump malfunction, blockage or leak, it can cause engine heating.

2. Faulty thermostat 

The thermostat of a vehicle’s engine manages the flow of coolant. It only allows the coolant to flow when the engine heats. The main valve of a thermostat stays shut if the engine is cool or idling.

For some reason, if the thermostat can’t regulate the coolant flow, it can result in engine heating. This happens when the thermostat fails to open the valves, preventing the engine radiator from receiving the coolant.

3. Damaged radiator fan

The coolant flows through the radiator after absorbing heat from the engine. The radiator’s cooling fan brings down its temperature by allowing the coolant to transfer the heat to the atmosphere.

In case the cooling fan is not functioning at an optimum level, it reduces the cooling efficiency of the coolant. This problem may occur due to a mechanical failure in the electric motor that runs the radiator fan.

4. Low engine oil

Engine oil in your car provides lubrication and helps to reduce excess engine heat as well. If your car is running low on engine oil, it can also cause excessive engine heating.

5. Damaged expansion tank

Almost all vehicles contain a coolant expansion tank these days. It regulates the entire cooling system’s pressure. But if the expansion tank is unable to release the pressure from the radiator, it can cause overheating in the engine.

How to diagnose an overheating engine?

If you can diagnose the warning signs early on, it can save your car from serious damage. You already know what happens internally when a car overheats. Now, let’s talk about the signs you should notice from the outside to diagnose if a car’s engine is overheating.

Signs of car overheating

Here are some of the signs you can notice to fix the engine heating issue as soon as possible.

1. Hot bonnet

It is common for the bonnet of your car to feel warm. But, if the bonnet gets extremely hot, it means that your engine is emitting excessive heat.

2. Temperature indicator

Most cars come with an indicator that reflects the engine’s temperature. This indicator will help you realise whenever your car’s engine generates excessive heat.

However, such an indicator reads the coolant’s temperature. So, you can’t trust it if car overheating is occurring due to coolant leakage.

3. Strange noise

If you hear a ticking noise coming out of the engine, it means a lack of lubrication. This happens when the engine oil loses its ability to lubricate due to excessive heating.

4. Coolant leakage

If you find coolant leaking beneath your car, it may be causing your engine to overheat due to a lack of cooling liquid.

5. Burning smell

If the engine overheats, you might smell an odour of burning oil. The smell intensifies as the heat rises up to damage plastic valves, rubber seals, etc.

6. Steam coming out of the bonnet

If you are able to see steam coming out of the bonnet, it can be a sign of engine heating. This happens when the coolant starts turning into steam after reaching its boiling point.

7. Reduced performance

When overheated, your car’s engine won’t be able to deliver its regular performance. Combine this with other signs, and you will know when to fix the excessive heating issue in your engine.

Engine overheating troubleshooting

You should know what to do when a car overheats to avoid extreme damage. Here are the steps you can follow in case engine heating occurs.

Step 1: Switch off the air-conditioning of the car to decrease the engine pressure.

Step 2: Park your car in a safe location, shut it off and let the engine cool down for 15-20 minutes.

Step 3: Check the coolant level and add more if required.

Step 4: Restart the engine or get it towed if you’re not able to start it.

Step 5: Take the car to a professional to check for leakage, blockage or any other damage.

Ways to keep your car engine in good condition

Use the following habits to prevent engine overheating in your car.

1. Regularly check the coolant level

This is a useful habit to avoid excessive heating in the engine of your car. Checking the coolant level in the radiator will help you add fluid whenever required. It is the most basic approach to prevent engine overheating. But make sure that the engine is cool before opening the radiator to check the coolant level.

2. Manage the AC usage to reduce engine pressure

Whenever you drive your car on a long journey, manage the use of air-conditioner (AC). Turn off the AC from time to time to avoid extra load on the engine. Continuously running AC increases the chances of engine overheating on long journeys.

You can also turn on the heater after switching off the AC and open the windows. This approach will allow the heat from the engine to release into the atmosphere through the cabin. This process is definitely a bit uncomfortable in summers but allows you to keep on moving without facing the issue of an overheated engine.

3. Keep an eye on the temperature indicator

When you are enjoying a long road trip, don’t forget to check the engine’s health through the temperature indicator. It may be a gauge or light on your dashboard, depending on the car you drive.

By checking the engine temperature, you can manage the speed or stop from time to time to avoid overheating.

4. Maintain a cycle of radiator flushing

Keeping an optimum level of coolant in your vehicle isn’t enough; you must replace it periodically. This can be done via a process called radiator flushing, which involves draining the coolant out of the radiator.

You can ask a professional at your regular service centre to flush the radiator. Make sure the mechanic cleans the radiator lines properly before filling up the new coolant. Doing this periodically will ensure optimum performance from the engine’s coolant.

5. Get the thermostat checked regularly

Another component you should get checked regularly is the thermostat. This way, you can fix any minor problems with the thermostat early on to maintain a smooth flow of coolant.

6. Notice any damages on the radiator cap

The cap on the radiator also plays its part. A loosened or faulty cap causes a pressure difference, which impacts the circulation of liquid. This cap contains a spring that loses its strength over time. Thus, you need to get it replaced whenever required to avoid overheating due to pressure differences.

7. Replace an old car battery

An old car battery has to work harder to deliver the required power. Weak batteries need to consistently recharge to deliver energy, which leads to excessive engine heating. It can cause overheating inside the engine. You should get your car’s battery checked by a mechanic. He will tell you if it is the right time to replace the old battery with a new one.

Tips to prevent your car from overheating

An overheated cabin can also impact the efficiency of the engine as the AC inside the car puts more pressure to cool down the interior. Hence, you must try to maintain a normal temperature of the car at all times. Below are some tips to help you avoid car heating.

1. Park in the shade

If you leave your car parked out in the sun, it can increase the temperature not just in the cabin but also inside the bonnet. Moreover, a heated cabin requires more time to cool down after turning on the AC.

You should find a parking space with shade, especially if you want to park the vehicle for a long period. Alternatively, you can cover your car to reduce heat absorption.

2. Leave windows slightly open for natural ventilation

If you keep all car windows closed while parking, it traps the hot air inside. Leaving the windows slightly open allows the hot air to escape.

If you have a sunroof in your car, open it just a little bit while parking. This creates natural ventilation, keeping the cabin cool.

However, you must keep the weather conditions in mind while leaving the windows open. You wouldn’t want to come back to a soggy cabin after sudden summer rainfall.

3. Use the car’s AC smartly

You must use the air-conditioner in a way that it doesn’t put too much pressure on the engine. For instance, don’t start the AC in recirculation mode. Instead, leave it in the fresh air mode for the first 10 minutes.

The recirculation setting will just move the same hot air inside. Once the cabin air cools down, you can switch the AC to the recirculation mode.

Frequently asked question

Can I drive my car after it overheats?

You should not drive an overheated car for long. If you keep on driving, it can twist the cylinders causing the head gasket to blow. You will end up paying a lot of money to get your car fixed. Thus, it is better to stop driving and let the engine cool down.

Will the car overheat when the AC is on?

In certain conditions, your car will overheat when the AC is on. These situations may include an overloaded AC compressor, faulty cooling system, damaged cooling fan, radiator not functioning properly, etc.

Smoke coming from the engine but not overheating; what to do?

Some type of fluid may have come in contact with the engine, resulting in smoke. The fluids like coolant, fuel, motor oil, or transmission fluid can cause smoke if they burn off on the engine surface. You should take your car to the service centre to get the leakage fixed.

My car’s radiator is overheating; what to do next?

If your car’s radiator is overheating, you should switch off the AC first. Then, stop driving, shut down the engine and allow some time for the radiator to cool down. Make sure that there is enough coolant in the system and it isn’t leaking outside.

If the radiator cools down in some time, drive it to a service centre for a checkup. A professional can tell you if there are any persistent problems causing your car’s radiator to overheat.

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