The engine temperature warning light, also known as the coolant temperature warning light, can appear on your gauge cluster for several reasons. To determine the cause, stop somewhere safe and turn off the engine as soon as possible. After everything has cooled down, you can begin diagnosing the problem.
Why is my Engine Temperature Warning Light On?
Whenever you start your vehicle, the engine temperature light will illuminate for a couple of seconds. This is only to verify that the bulb is working. If it remains on, it’s because the computer has detected a problem in the system.
In most cases, the issue is related to coolant temperature or fluid levels. However, the problem can extend to other components. For example, fluid levels might be low due to an opening in the container through which liquids are constantly leaking out. There can also be mechanical damage to one of the coolant system components.
What is the Engine Temperature Warning Light?
The engine temperature warning light or engine overheating light is typically represented by a thermometer submerged in two flowing waves. Depending on the make and model of your vehicle, there can also be a symbol written as “TEMP” or “ENGINE OVERHEATING.”
When there is an issue with your coolant, the warning light will illuminate red or sometimes yellow. The purpose of this is to indicate that there is either a coolant fault or the engine is too hot.
What Does it Mean if the Engine Temperature Warning Light is Flashing?
Your engine is kept cool by a mixture of water and ethylene glycol known as coolant or antifreeze. This liquid circulates throughout the engine system to maintain safe operating temperatures. Engine temperature warning light bulbs will start flashing red when the coolant is failing to move through the system and keep the engine running smoothly.
If you’re driving when the light turns on, aim to pull over as soon as you safely can. Then shut down the engine and let your vehicle cool down for 20 to 30 minutes before inspecting anything. Once the engine is cool enough, you can use a rag or glove to remove the radiator cap, which pressurises the system to prevent the liquids within from boiling.
It’s important to be careful when checking the coolant as the steam can burn you if it’s still too hot. If you find that the problem is low fluid levels, you can safely refill the container with water so that you can head to a service centre for a more thorough check-up.
How Does the Engine Temperature Warning Light Work?
The engine temperature light car warning is almost always located on either side of the temperature gauge in your instrument cluster. You can use the temperature gauge as a useful guide to determine whether the system is too hot. Under normal driving conditions, the temperature shouldn’t exceed 100 degrees Celsius. Keep in mind that this is separate from the oil temperature gauge.
Your engine contains a number of measurement tools designed to keep track of the functionality of key components. This includes a type of thermometer that measures temperatures, as well as a tool for measuring coolant levels. If any component detects a problem, a signal will be sent to the onboard computer.
Modern cars will also save a diagnostic file that contains information about the event. This can provide useful details for your mechanic to work with later on.
What are the Common Reasons for the Engine Temperature Warning Light Will Come On?
Most causes for the engine temperature light on the dashboard turning on pertain to an issue with the cooling system.
Prolonged Stalling
Without enough cool air entering the radiator, fluids overheat quicker, preventing them from doing their job. This is why keeping the engine running for extended periods without moving can activate the temperature light. The good news is that if this is the reason for the light turning on, it’s unlikely that there are any actual mechanical issues.
Excess Load
When putting your engine under pressure, such as by driving uphill with a heavy load, the radiator won’t receive enough air to regulate coolant temperatures. This is similar to the first cause and likely means that no mechanical problems or leakages are present.
Hot Weather
While we can turn the air conditioning on to cool ourselves while driving on a hot day, the engine can’t. Hot outdoor temperatures, especially when coupled with inner-city driving and constant braking in traffic, can lead to overheating of engine coolant. Therefore, consider your surroundings and conditions if the engine temperature light turns on.
Low Coolant Levels
If coolant levels fall below the threshold of safety, the engine temperature light will activate. This is to ensure that water levels are addressed before further damage is caused. With regular check-ups and maintenance, you can avoid this from being a cause of the light turning on.
Remember that you can use normal distilled water to top up the container as a temporary solution. However, this should only be done to get to a service centre or mechanic.
Mechanical Damage
In the worst cases, the engine temperature warning light has turned on due to damage in the system. Affected components can include the radiator, service belt, and water pump. If all of these parts are intact, then a dry or damaged gasket might be to blame. This is more often the case with cars that are several years old.
Is it Dangerous to Drive With the Engine Temperature Warning Light On?
While your car might still be drivable, continuing to run it with the engine temperature warning light on will only cause further damage and can lead to more costly repairs. At the very least, you should stop and let the engine cool down for around half an hour before driving further.
Will my Car Fail its MOT if the Engine Temperature Warning Light is On?
Given the problems an engine temperature warning light indicates, it makes sense that a car will not pass its MOT if the light is on. Therefore, you should have it fixed before going for the MOT, as it’s a recognised criterion for failure.
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