Combustion engines are driven by a series of controlled explosions. These constant explosions generate enormous amounts of heat. As a result, engines need a series of passageways and a pump to circulate coolant throughout the engine block and maintain the overall temperature.
The car’s computer constantly monitors the coolant temperature and overall fluid level to ensure that the proper temperature is maintained always. A warning light is displayed on the dashboard if the coolant temperature is too hot.
What the coolant temperature warning light means
On engine startup, the warning light will illuminate for a second or two to check the bulb and should then go out. If the warning light is illuminated even after startup, it indicates that the car’s computer has detected an issue within the system. The most common reasons for the warning light to displayed are the temperature or fluid level of the coolant.
If you are driving when this warning light goes on, pull over safely as soon as possible and shut off the engine to let everything cool down. Let the engine cool down for at least 30 minutes before attempting to remove the radiator cap and remember to use a thick rag to protect your hand when you do so. Never attempt to remove the radiator cap off of a hot engine. The radiator cap is designed to pressurize the system so that the water doesn’t boil as easily. Removing the cap from a hot engine will cause the coolant to start boiling and the steam will most likely burn you. Once the engine has cooled, check the overall fluid level of the coolant. If the level is low, you can add just water temporarily so that you can drive somewhere to get the car checked out.
Keep in mind that a low coolant level means a leak is present which needs to be remedied at the earliest. Otherwise, your car will eventually be low on coolant again and run the risk of the engine getting overheated. The car’s computer will typically save a code when faced with any issues so having a scan tool hooked up to the car can be of immense help in identifying the problem.
Is it safe to drive with the coolant temperature warning light on?
While the car is still driveable, you run the risk of causing significant damage to the engine by letting it run too hot. As mentioned earlier, if the light comes on, you should pull over as quickly and safely as possible. When the light has turned off, you can drive the car again, but keep an eye out for the light to come on as it most likely will until the problem has been fixed. Even if you have to pull over every couple of miles to let the engine cool down, it’s worth the hassle to help prevent the engine from overheating.
As always, our certified technicians are available to assist you in diagnosing any issues with your cooling system.
This article originally appeared on YourMechanic.com as What Does the Coolant Temperature Warning Light Mean? and was authored by Spencer Cates.