What Does It Mean When The Car Temperature Light Turns On?
The engine temperature light means your engine is overheating. Not every car uses this symbol. Some cars just have a text warning that says “TEMP” or a description of what is happening. This is a very serious warning and you should stop driving immediately. Driving with this warning light could destroy your engine.
This warning light is controlled by the engine coolant temperature sensor. Engine coolant is liquid that circulates around your engine. It removes heat from your engine and releases it through the radiator. The engine coolant temperature sensor measures the temperature of your engine coolant. When the sensor detects the coolant temperature is hotter than the normal engine temperature (190-220 degrees Fahrenheit) it can turn on.
Common Reasons For The Car Temperature Light To Come On
- Broken temperature sensor (false warning)
- Coolant fluid is low
- Failed coolant fan
- Coolant system leak
- Overworked engine (especially in hot climates)
- Low oil level
- A damaged or malfunctioning radiator
- Blown head gasket
Can I Drive With The Car Temperature Light On?
If the engine temperature light turns on, you need to stop driving immediately. Continued driving will damage and or destroy your engine. Engines can cost around $4500-$6000 so you want to be very careful.
When you see the engine temperature light follow these steps:
- Turn on the heat to vent hot air
- Find a safe place to pull over
- Turn off your engine
- Do not open the hood because you could get badly burned
- Call a tow truck to take your car to a repair shop
How Do I Fix The Car Temperature Light?
Before you fix this problem, you need to diagnose what is causing the problem. The warning light could have been triggered because of a faulty temperature sensor or a coolant leak. First find the cause of the problem and then fix it.
Before doing anything under the hood when you have an engine temperature warning light make sure the engine cools down for at least 20 minutes. If you don’t wait, you could get seriously injured.
| Problem Cause | How To Fix | Cost To Fix Yourself |
|---|---|---|
|
Broken Temperature Sensor |
Read the sensor with live data from an OBD2 scanner like FIXD (if you are getting no reading, the sensor is broken and needs to be replaced) Drain the coolant from your radiator Disconnect the sensor and install the new sensor Refill the coolant fluid |
New Temperature Sensor ~ $25 |
|
Coolant Fluid Is Low |
Check the level of the coolant (if it is low you need to add engine coolant) Never open the coolant reservoir when the engine is hot |
Replacement Coolant ~ $20 |
|
Coolant System Leak |
Check to see if there is a visible leak in the radiator (you may see a hole or puddles of green/orange coolant under your car) Check to see if the radiator cap is leaking (if the seal is worn the fluid may be leaking out of the cap) If there is a leak in the radiator use a stop leak If the cap is worn or leaking, buy a replacement |
Stop Leak ~ $10 Replacement Cap ~ $10 |
|
Blown Head Gasket |
If there are no signs of a radiator leak, there is white smoke coming from exhaust, and milky coloration in the oil you may have a blown head gasket You should take your car to a mechanic if you think you have a blown head gasket |
Replace Blown Head Gasket ~ $1500 - $2500* *You might need a new engine |
Is Your Car Overheating?
If you notice the following symptoms, your car may be overheating:
- There is steam leaking from the hood of the car
- The temperature gauge is in the red
- There is a smell coming from the engine
If you notice the temperature gauge starting to climb or the engine temperature warning light has turned on roll down the windows and turn off your A/C. A/C puts a lot of stress on your engine and you want to reduce the engine load. If that isn’t helping, turn on the heat. This might sound counterintuitive, but turning on the heat cools the engine. This is because the hot engine heats up the air that gets vented into the cabin, so this will cool the engine.
Try not to brake more than you have to. Braking means you will have to accelerate to get back up to speed. Acceleration puts a lot of stress on the engine. If possible, try to idle when you’re stuck in standstill traffic.
At FIXD, our mission is to make car ownership as simple, easy, and affordable as possible. Our research team utilizes the latest automotive data and insights to create tools and resources that help drivers get peace of mind and save money over the life of their car.
