Home Diagnosis and TroubleshootingDashboard Warning Lights Temperature Light Car: How Catastrophic Can It Get?

Temperature Light Car: How Catastrophic Can It Get?

by Jordan Harris
Temperature Light Car

Combustion engines run on a series of controlled explosions. They usually generate a large amount of heat because of these constant explosions. Hence the engine needs a cooling system to enable control of this high temperature and prevent the engine from overheating. Therefore, a coolant always circulates through the engine block to help maintain the ideal temperature. If there is any fault in this system, a coolant temperature light car is triggered if the engine overheats.

A car comprises a computer that will constantly monitor the temperature of the coolant. It will also check on the fluid levels too to ensure the recommended coolant level and temperature is maintained. A warning light: coolant temperature light car, displays on the dashboard if the coolant temperature is too hot or the fluid levels drop drastically.

A car has several lights found on the dashboard. They help in informing the driver of any malfunction or potential threat in the car. If you are new to driving, the warning light symbols may seem unfamiliar to you. Understanding them is very crucial. This can help you give your car the best care to enable it last longer. It can also help in saving you unwarranted repair costs and save your car from premature breakdown.

Having a coolant temperature light car illuminate is a clear sign the engine is getting excessively hot, and the driver needs to look into this immediately. When the coolant light illuminates, it shouldn’t be taken lightly. An overheating engine is very dangerous since it can even lead to a fire or explosion in your car in the worst-case scenarios.

In this article we discuss;

What Is Engine Coolant

An engine coolant is a compound of water and ethylene glycol (C2H6O2). It’s also referred to as an antifreeze. It helps in absorbing heat produced by the engine then disperses it to another location. The liquid is usually inserted into a circuit known as a cooler.

This cooler is an assembly of different components. One of the most essential components in this cooling system is the radiator. The radiator exploits the flow of cold air generated by the movement of the car to help cool the hot coolant.

The continuous flow of this fluid keeps the engine at a precise temperature and prevents the coolant temperature light car warning from coming on. If any component within this cooling system gets damaged, or in case there is a leak within this cooling circuit, the coolant levels will drop and this can cause the engine to overheat and even melt in severe cases.

To avoid such serious instances, all cars have a coolant level indicator, a warning light, and a temperature warning light to help alert the driver of any unusual conditions within this system such as possible overheating or low coolant levels. If the coolant level drops and the temperature rises, then are sure there is a possible leak within the system.

What It Means When Temperature Light Car Illuminates

When you start the engine, the temperature light car should illuminate for a few seconds then go off. But if you start the engine and the light stays on, then it means that the onboard computer has detected something wrong within the cooling system and a low coolant level probably causes this.

If you are driving along the road and the coolant temperature light car signal illuminates, then you need to get off the road immediately then shut off the engine to let it cool first. This will be a clear signal the engine is overheating and you shouldn’t risk further by keeping on driving on a heating engine.

Let the engine cool down for about 30 minutes before you can attempt to open the radiator cap. Ensure you use a thick rag when opening the cap. This will help protect your hand from burning. Never attempt to remove the radiator cap when the engine is still hot. The radiator cap helps to pressurize the cooling system so that the coolant does not boil easily.

If you try to remove the cap when the engine is still hot, the coolant will boil and the steam under high pressure will burn you. After the engine has cooled down, you can then check the coolant level. If you find out that the coolant levels are low, you can just add water as a temporary fix to enable you to drive safely to the nearby service bay to have your car inspected.

A Reminder

Always remember that a low coolant level is a sign of a leak that should be sealed immediately. Failure to attend to this as soon as possible, you risk your car running low on the coolant again. This may pose the danger of your engine heating again and again.

It can eventually lead to the engine blowing up or melting. Since your car’s computer will always save codes related to this problem, it’s always important to have an OBD 2 scan tool hooked up to help decipher the problem easily.

Types Of Temperature Light Car

Different manufacturers currently use just one indicator lamp that can illuminate either blue, yellow, or red signals depending on the condition of your cooling system. Each color and shape of the indicator light signals a distinct problem or warning. It’s important to know what these three colors mean so that you can find where to trace the root cause of the problem and have it fixed.

Blue Coolant Temperature Light Car

This does not show an emergency. It means that the engine is not at operating temperature. So don’t rev the car so high when you first hit the road. Doing so can lead to rough wear and tear on the engine.

Immediately once the vehicle is warmed up this light should go off. If the light continues illuminating even after driving for several miles then know that you are driving through the arctic or your car has a problem. You need to seek the services of a mechanic to see why your car isn’t reaching operating temperatures.

Yellow Coolant Temperature Light Car

The yellow coolant light also does not show an emergency. The likely culprit in this situation is the low coolant levels. Even if there is just a slight drop in the coolant levels, this can still trigger the sensor depending on your type of vehicle.

If you live in cold areas, it’s obvious the cooler may contract to lead to these lower levels. The right step to take is simply to top up the coolant. However, it can also be more likely that your car has a cooling system leak. You can check the coolant levels yourself if you have confidence in your ability.

You can just open the hood, allow the engine to cool for at least 30 minutes, and then check the levels. If the levels are low, then you have to find the leak. Sealed engine coolant will not just evaporate like that. No way! A low coolant means your car leaks.

If you aren’t a DIY person and probably you don’t have the time for the hassles, you can book an appointment with a professional service mechanic to get the sealing done for you.

Red Coolant Temperature Light Car

This shows a huge emergency. You just need to stop immediately for a reason. The red indicator means your car is overheating. It’s mostly witnessed during the warmer months but can also happen during winter. If you see this light come on, then it means that your car is in seriously big trouble and you don’t need to still keep it on the road.

You need to get off the road and shut the engine immediately. The quicker you respond immediately you see thin indicator light, the better chance you have of not creating permanent engine damage. It would be appropriate to have your vehicle towed to the nearest service bay for a check-up.

Temperature Light Car: What Is The Normal Coolant Temperature

Despite the temperature gauge being able to reach 130 degrees Celsius. The temperature of the coolant should always be kept way below this for it to be conducive to the normal operation of the engine.

The temperature of the coolant under normal driving conditions should be between 80 to 90 degrees Celsius. However, this can rise significantly if the engine has been running for a very long time. For the coolant recirculation system to run efficiently, the engine must be in full operation.

What Happens If Coolant Gets Too Hot

Some major problems can contribute to engine overheating. Some of the most usual factors that contribute to engine overheating include a blown radiator, a blown head gasket, cracked cylinder heads, and cracked blocks.

However, other major and costly issues can be a product of an overheating engine. Extreme heat can cause various internal engine components to expand leading to other problems like damaged valves and scuffed pistons. Very high engine operating temperatures can also contribute towards detonation which can damage internal components of the engine.

Common Causes Of Engine Heating

Different causes contribute to engine overheating. It if this causes that trigger the coolant temperature light car. It is important to know these causes so that when they happen you know how to deal with them before they become severe and help save your engine. Here are some of the common causes of engine overheating.

Leaks Leading To Low Coolant Levels

As stated earlier, your car comprises a cooling system that is responsible for ensuring that your engine is always cooled to the recommended temperature. This normally happens when the heating effect has exceeded the recommended threshold. The coolant is always kept circulating in the engine, therefore, ensuring the temperature is lowered accordingly.

Every car has a given level at which the coolant should always be. If there is any drop in the level of the cooling fluid, then the engine will not get the sufficient amount of cooling required. At this point, you will probably have to deal with engine heating problems if you don’t top up the coolant immediately.

Coolant levels can drop because of several issues. The most significant drops in fluid levels can be noticed when there is a leak within the cooling system. It is not easy to identify the exact point where the leak is. It can be in the hoses, around the transmission, or even around the engine.

This is why it would be important to have your car inspected by a professional mechanic as it won’t be difficult for them to identify the source of the leak.

Failed Thermostat

A thermostat forms part of the cooling system. Its sole responsibility is to control the flow of the coolant around the engine. Therefore, a thermostat will open whenever the temperature in the engine rises to a certain level.

Once the thermostat opens, the coolant will flow freely around the engine hence helping to lower the temperature. Alternatively, if the engine temperature fails to rise to a required threshold, then the thermostat stays closed to prevent the engine temperature from being lowered further by the coolant.

Due to wear and tear, over time, the thermostat may become faulty by either staying open all the time or stay closed all the time. A stuck open or stuck closed thermostat can be a big issue to your engine as it can lead to constant overheating.

Faulty Water Pump

The water pump is also another crucial component of the engine cooling system. It is the one responsible to ensure certain speeds and pressure to help the coolant circulate the engine effectively helping to bring the engine temperature down.

Since the water pump is a mechanical component of this system, it is therefore prone to damages especially at the blade impellers.

If the pump fails to pump the coolant sufficiently around the engine, it is advisable to take the necessary measures immediately to have it repaired or replaced. This will help avert severe consequences that may arise as a result of a failed pump.

Damaged Or Obstructed Radiator

It is important noting that once the temperature of the coolant has risen; it flows back into the radiator so that its temperature can be reduced in preparation for a repeat cycle. If the coolant gets very hot and the radiator is malfunctioning and is unable to cool down the coolant fluid, it will fail to lower the engine temperature.

This is the time the engine will keep overheating due to radiator issues. At this juncture, it would be important to replace the radiator immediately to protect your engine from stalling.

Troubles With Cooling Fans

The radiator relies heavily on the cooling fan to help provide airflow when the vehicle is idling or moving at a slower speed. If the fan malfunctions either due to internal failure or a circuit problem, the engine will keep overheating because the cooling fan is unable to provide airflow to help lower the temperature of the coolant fluid in the radiator.

Internal Engine Problems

Many internal engine problems can lead to engine overheating. Some of these issues include a blown head gasket, cracked cylinder heads, and cracked engine blocks. These can lead to internal coolant leaks resulting in overheating.

Depending on the location of the leak, the coolant may either enter the engine’s combustion chamber and get burned or it can get into the lubrication system and mix with engine oil. Either of the two scenarios can lead to low coolant levels and engine overheating.

It is important to note that a blown head gasket, cracked cylinder heads, and cracked engine blocks are often caused by an overheating engine. Having them faulty can further escalate the engine overheating.

How Safe Is It Driving An Overheated Car

While the car will still be able to move, it’s not safe driving on an overheating engine. There is the risk of completely damaging the engine plus other vehicle components if you let the engine run too hot.

That is why it is advisable that when the coolant temperature light car signal illuminates, you need to pull your car off the road as quickly as possible the turn off the engine to allow it to cool for around 30 minutes. Inspect for possible low fluid levels. If that is the case the simply add water as a temporary fix before you can arrange for a lasting solution.

Remember the light will still come on provided that the problem hasn’t been fixed. Even if it will involve having small breaks to allow the engine to cool. It is worth it than continuing to drive on an overheating engine and end up causing more severe damages.

What Are The Damages Of Overheating

You should not allow an overheating engine to cause more severe and costly damage to your engine. You should have the problem fixed immediately by a professional service mechanic. Otherwise, failure to do so early enough can end up stalling your engine and its components completely. You can just imagine the cost of replacing a new engine or rebuilding the already damaged engine. This can get into several of the thousands of dollars.

How Long Does It Take For The Car To Cool After Heating

If a car heats up and the coolant temperature light car illuminates, get the car off the road, switch off the engine, open the lid of the hood and wait for at least 30 minutes for the engine to cool down. To be on the safe side and avoid hot engine fluid-related burns, you can let the engine cool for one to two hours.

Cost Of Fixing A Coolant Temperature Light Car

The cost of fixing the problem causing the temperature light car signal to illuminate will greatly depend on the source of the underlying problem. If the source of the problem emanates from failed coolant temperature sensors, the repair cost would range between $134 and $155.

However, if the source of the problem is because of a blown head gasket which is one of the most expensive repairs you may deal with, then this would cost between $1600 and $2000. If the problem emanates from the thermostat, the repair cost may range between $197 and $227.

If the coolant temperature light car illuminates because of a coolant leak problem, it can be very difficult to determine the final cost of repair. This will depend on how severe the problem is. If the leak is small, you may end up spending $100. If the leak is more severe, you may end up paying $800 or even more to have the problem fixed.

Sadly, with issues that involve coolant leaks, you cannot fix them yourself at home. This means that you will have to pay for the huge repair cost that is involved. There is a very big difference between fixing a faulty thermostat and sealing a coolant leak.

How To Prevent The Engine From Heating

If you may be worried about your car overheating when you are on the road then you have to enroll for a breakdown cover just in case should the worst thing happen when you are on the road then your needs will be easily met.

However, there are also more precautionary measures that you can put in place to protect your vehicle from overheating. They include:

  1. During summer always keep your car cool by parking it in the shade. You can also keep the interior of your car cool by using sunscreens.
  2. Always ensure that you constantly check your temperature gauge and coolant levels. You can always add coolant whenever you feel it’s necessary. Ensure you also let your engine cool down when needed.
  3. Always have extra coolant in your car whenever you are on the road. This can help you make a top-up whenever it seems necessary.
  4. Always allow air to flow inside your car by opening windows regularly and the floor vents. This will allow warm air to escape from the cabin leaving your car’s interior at a cool temperature.
  5. Make it a routine to have your car inspected and if possible serviced by a professional mechanic. This should involve the cooling system is flushed out and cleaned. It is recommended to have this done every 40,000 miles.


A coolant temperature light car is a very important warning light. It helps to indicate that the temperature of the engine is rising beyond the ideal threshold. When this happens, your engine risks blowing off completely. It’s unimaginable the cost that comes to be able to replace a blown engine.

It ranges into thousands of dollars. It’s very important to always take the coolant temperature light car seriously. In the worst-case scenario, you just need to stop your car immediately, shut the engine, and tow the vehicle to the nearby service bay to get it fixed.

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