What is the thermometer icon on my car dashboard?
The thermometer icon on a car dashboard is most often the engine’s coolant temperature warning, signaling the engine is overheating or there is a cooling-system issue. In some vehicles, the same symbol may indicate the outside ambient temperature. The exact meaning depends on your make and model, so consulting the owner’s manual or a dealer can clarify your specific icon.
Common meanings of the thermometer icon
To guide drivers, here are the two most frequent interpretations you might encounter. Note that color, location, and accompanying lights vary by vehicle.
- Engine coolant temperature warning: the engine is overheating or the cooling system has a fault. This is usually shown in amber or red and is a signal to stop driving and check the cooling system.
- Outside temperature indicator: in some cars, the thermometer symbol accompanies the current outside air temperature reading in the instrument cluster or on the infotainment display.
- Engine cold-start indicator (less common): in certain models, a blue-ish thermometer can indicate the engine is still cold and warming up; this typically clears once the engine reaches normal operating temperature.
In short, the icon is most often a coolant-temperature alert, but some vehicles use a thermometer to display ambient temperature. Always consider color, whether other warning lights are on, and your current driving situation.
What to do if the icon signals engine overheating
If the thermometer icon appears in amber or red while driving, treat it as a possible emergency for the engine cooling system. Here’s how to proceed.
- Safely pull over as soon as you can and turn off the engine to prevent damage.
- Wait for the engine to cool before opening the radiator cap or checking coolant level. Opening a hot cooling system can cause burns and injuries.
- Check for obvious issues such as low coolant level, leaks, or a blocked/loose radiator hose. If you notice coolant on the ground or a sweet smell, avoid driving further and call for assistance.
- Once cooled, you can check coolant levels with the engine cold and refill if you have the correct coolant and follow the manufacturer’s guidelines. If you’re unsure, call for roadside assistance or visit a shop.
- After addressing the coolant, start the engine and monitor the gauge. If the warning reappears or the engine overheats again, stop driving and seek professional service.
Overheating can damage critical engine components, so a cautious, timely response is essential rather than continuing to drive.
What to do if the icon is an outside temperature indicator
If the thermometer is simply showing outside ambient temperature, it’s informational rather than an immediate safety issue. Use the reading to plan for weather conditions and fuel economy considerations.
- Check the display context: confirm whether the icon is paired with a numeric temperature value (e.g., 72°F / 22°C) on the dash or infotainment screen.
- If the ambient reading seems obviously off (for example, in a very cold climate when you know it’s warm outside), reset the sensor by cycling the ignition or by restarting the car. Some vehicles require a service to recalibrate or replace a faulty ambient-temperature sensor.
- In most cases, ambient readings are not a safety concern. If you rely on the reading for weather planning, you can cross-check with a trusted weather source until you verify the sensor’s accuracy.
When it’s an ambient temperature display, there’s no risk to the engine from the icon itself; however, a faulty sensor can mislead you about weather conditions and should be checked if readings are inconsistent.
Model-specific notes about thermometer icons
Dashboard symbols can vary by manufacturer. Some brands use a blue thermometer to indicate the engine is cold, while others use a yellow or red version for overheating. A few models also place the ambient-temperature symbol in a separate part of the display. Always refer to your owner’s manual for the exact meaning on your vehicle.
Blue thermometer icon
A blue thermometer often indicates the engine is cold and warming up. This is typically benign and should disappear as the engine reaches normal operating temperature.
Red or blinking thermometer icon
A red or blinking thermometer is usually a more urgent warning about overheating or a cooling-system fault. Do not ignore it; pull over safely and investigate or contact roadside assistance if you cannot diagnose the issue on the spot.
Summary
In most cars, the thermometer icon is the coolant-temperature warning, signaling overheating or cooling-system trouble. In some models, it denotes outside ambient temperature. If you see a warm amber or red icon, prioritize engine cooling checks and safety. If you see a blue icon, it typically indicates the engine is cold and warming up. Always consult your owner’s manual for your vehicle’s specific iconography and seek service if the warning persists.
