Mazda CX-3 Forums

My usually blue coolant light turned red yesterday . In checking the handbook I was directed to check the coolant reservoir in the engine . No overheating or jeans were found but the coolant level was below full but above empty. I added more . On starting the engine after this the red coolant light was visible but turned blue within a second . I took the car for a short drive thinking that the sensor would recognise the added new coolant and the red light would not show again . Not so , after starting the engine several times the red, then the blue lights in quick succession still appear . I’ve had this car over a year and the light has always been blue . Is there something I need to do to erase the red light from the memory or is there something else I’m missing ??

Do you get a message in the infotainment system when the redlight is on?

The blue thermometer light will change to flashing red when the coolant is too hot. It then changes to being on continuously red if the coolant temperature is extremely hot, at which point engine damage is possible if the vehicle is driven.

Did you check the coolant level in the radiator (when the engine is cold) as well as the expansion bottle?

As your light is changing from red to blue very quickly on startup, and assuming the coolant level is correct, I think you may have a faulty temperature sensor, or a coolant flow issue. My advice would be to raise the issue with your authorised Mazda garage.