What it means
A blue coolant temperature light usually indicates that the engine is still cold after starting. Blue commonly signals information rather than a fault, but colour and exact behaviour vary by manufacturer; check the owner's manual.
What the symbol looks like: A thermometer above wavy lines representing coolant, sometimes shown in blue.
Why it comes on
- The engine has just been started
- Cold ambient weather
- The vehicle is designed to show a cold-engine indicator
- A temperature sensor or thermostat fault if the light behaves abnormally
What to do
- Check the owner's manual to confirm the light's meaning for your vehicle.
- Start driving gently when safe rather than leaving the engine idling to warm up.
- Avoid high engine speed, hard acceleration, and heavy loads while the engine is cold.
- If the light stays on unusually long or other warnings appear, arrange a check.
Can I keep driving?
You can usually drive while this indicator is on, but drive gently until the engine warms. Avoid hard acceleration and heavy loads; stop if a high-temperature warning appears.
Symbols and colours differ between makes and models. Your owner’s manual shows the exact lights of your car.