Low Coolant Temperature Indicator
What it means
Shown as a blue thermometer, sometimes dipped in wavy lines, this light means the engine is still cold and has not reached operating temperature. It is an information light, not a warning, and normally goes out after a few minutes of driving. If it stays on for a long time in normal driving, the thermostat may be stuck open or the temperature sensor may be faulty.
Symptoms4
- Blue indicator on after start-up, going out after a few minutes of driving.
- Indicator stays on for a long time or comes back while cruising on the highway.
- Weak cabin heater in cold weather.
- Higher fuel consumption.
Possible causes5
- Engine cold after start-up, which is normal.
- Cold weather or very short trips that do not warm the engine.
- Thermostat stuck open, so the engine never reaches operating temperature.
- Faulty coolant temperature sensor or wiring.
- Low coolant around the sensor (less common).
How to diagnose4
- Drive gently for a few minutes and see whether the indicator goes out.
- If it stays on, check the coolant level with the engine cold.
- Check whether the cabin heater works normally after driving.
- At the workshop: compare the actual engine temperature with the sensor reading on a scan tool, and read codes such as thermostat codes.
How to fix5
- Drive gently, without hard acceleration or high engine speed, until the indicator goes out.
- Top up coolant if low and fix the leak.
- Replace the thermostat if it is confirmed stuck open.
- Replace the coolant temperature sensor or repair its wiring if confirmed faulty.
- After the repair, confirm the indicator goes out within a normal warm-up time.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
Usually there is no cost because the light shows a cold engine; the cost starts with a temperature sensor and reaches the upper end for a thermostat replacement.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026
Frequently asked questions
Should I wait for it to go out before driving?
No need to idle for long. Drive off gently and avoid hard acceleration and high revs until it goes out; this warms the engine faster than idling.
The light stays on the whole trip. Is that dangerous?
Not immediately, but it usually means a thermostat stuck open or a faulty sensor, which raises fuel use and wear, so have it checked soon.
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What was wrong? (optional)
This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.
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