Coolant Light On But Not Overheating (What To Do? Explained)

If the coolant warning light illuminates the dashboard of your vehicle, then this can be a sign that your engine is overheating. So for your vehicle to work and operate, there are a series of explosions made in a combustion chamber. These explosions will move the piston up and down, and it will start to power your vehicle. 

With that, there will be heat. So to keep your engine from welding itself back together, the coolant will be pumped around the engine. If this process fails, the engine’s temperature will increase and then trigger the coolant warning light. Many drivers would panic at the sight of a coolant light on. 

This is because drivers know the function of a coolant. A coolant is there to keep your vehicle and engine from overheating. Overheating is a serious situation, and you do not want your engine to be overheated. 

So if your coolant light is on, you should immediately check for any overheating, and you have to refill your coolant immediately. However, there are moments when your coolant light will turn on, but your vehicle is not overheating. 

This puzzles a lot of drivers. This article is made to tackle coolant light, but there is no overheating. Let’s get started. 

Coolant Light On But Not Overheating

Why Is My Engine Coolant Light On And My Coolant Is Full?

The top common reason for engine coolant light is that the coolant level is low. A floating sensor in the coolant tank might trigger the warning light if the coolant ll drops. So you might need a coolant change for that. 

A low coolant level is caused by a leak, either in the reservoir or in the lines. These leaks are a serious problem, and they are not diagnosed easily. 

They are also not fixed quickly. And as the coolant will travel around the engine, there might be various places where it will leak, like a water pump, hoses, or a radiator. 

How Do I Know If My Coolant Level Sensor Is Bad?

A coolant level sensor is an electronic sensor that measures your coolant level in the engine. It’s usually installed in the coolant reservoir or the radiator, and it will measure the amount of coolant in the system to ensure that it is on the correct level. If the level drops below the safe level, the low coolant light will turn on and alert the driver that the coolant should be refilled. 

A low coolant is harmful, and it is dangerous to hate because the coolant is the one that keeps the engine from overheating during a regular operation. Therefore, it is necessary to have your coolant changed and the coolant level sensor if it is broken. So to know if your coolant level sensor is broken, here is a list of what happens.  

Your Coolant Light Will Stay On

One of the typical symptoms of a broken or faulty coolant level sensor is that the coolant level light will stay on. If the sensor is short, it will prompt the coolant level light to stay on. This is an issue because it will permanently illuminate the coolant light and not alert the driver if the coolant level drops appropriately. 

There Is A Low Coolant

One symptom of a problem with the coolant level sensor is low coolant. If the coolant level drops low and the light will not come on, the wiring or the sensor might have a problem. 

The sensor is made specially to defect a low coolant. Therefore, if the level in their reservoir will drop, and if the light will not come on, then it can mean that there is a problem with the sensor or the wiring. 

There Is An Overheating Engine

If the engine is overheating, it can also mean a problem with the sensor. Many issues cause an overheating engine, and some of them might not be related to any sensors. But if the overheating is related to the coolant level, this can mean that it indicates a problem with the sensor. 

If the coolant level drops low to cause overheating, and if the low coolant light is not illuminated, the sensor has a problem. If the coolant level is playing a massive role in the engine’s performance, it does have a particular purpose of protecting the engine from dropping low in the coolant.

Is It Safe To Drive With A Coolant Light On?

The coolant pressure warning light is essential because it tells you if your engine is overheating because of a low coolant. If the light is turned on and you wonder if you can continue to drive, then the answer is no. If there is an overheated engine, this can cause damage to your engine, and you will need to have it repaired soon. 

So you need to have it repaired. The damage to your engine might be because of overheating, and it can be a failed head gasket to damaged pistons and valve stems. There can also be cracks in your cylinder. It can cost a repair, and you must avoid it. 

If you see a warning light turn on, you should pull over and turn off your engine if you are driving. Next, you need to let your engine cool down and check your vehicle’s coolant level. If the coolant is low, you need to fill it with fifty percent antifreeze, and fifty percent distilled water. 

This is temporary, though. A coolant pressure warning light means that there is a low coolant, which can be because of a leak in the system. You need to fix the issue fast because a leaking coolant can damage your vehicle. 

How Do I Turn Off The Low Coolant Light?

The easy way to fix a low coolant light is to fill the coolant back into its sufficient level. Then, allow the coolant to soak back into the system. Opening your radiator cap, there will be indications like max or min, which will indicate the level of the coolant mixture in your tank. 

What To Do When You Have A Bad Coolant Level Sensor?

The coolant sensor can be found in the coolant reservoir bottle. You can replace the reservoir. But if the sensor is wrong, you can try unplugging the sensor in the coolant reservoir bottle. 

Unscrew the screws that are holding the reservoir bottle. If the bottle is loose, tilt the bottle slightly toward the tilt, there is a wire coming out of your reservoir bottle. Unplug the sensor plug and connect to the reservoir battle. 


In summary, there are moments where the coolant light will turn on and cause anxiety to car drivers. But then they notice that their vehicle is not overheating. 

This might be a cause of a back coolant level sensor. So you have to have it fixed to display a suitable warning.

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Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more