Why does my radiator fan come on

[Ismaeel]

I have a 2006 Yaris 1.3 vvti and basically when on idle the radiator fan will come on roughly every 10 minutes is this normal or is it a sign the car is over heating ?

[APS]

If the car is left idling and up at normal working temperature then yes the fan will come on at regular intervals. Completely normal.

How come you ask - has the behaviour changed do you think? Or have you just not noticed this before?

How often it comes on depends on the ambient temperature of course. In winter it will take longer for the fan to come on compared to summer.

[anchorman]

Just now, APS said:

If the car is left idling and up at normal working temperature then yes the fan will come on at regular intervals. Completely normal.

How come you ask - has the behaviour changed do you think? Or have you just not noticed this before?

How often it comes on depends on the ambient temperature of course. In winter it will take longer for the fan to come on compared to summer.

….and whether the a/c is on.

[APS]

Just now, anchorman said:

….and whether the a/c is on.

Good point. If the car has A/C and it is switched it on, the fan will come on more frequently, in fact, it only stops running briefly and comes back on again.

[Rhymes with Paris]

If the dash lights,ie no temp gauge,are the same as the earlier Yaris it's just a blue thermometer symbol for when cold, and a red one if too hot.

No light on if normal operating temperature.

[Stevie J]

It's completely normal for the radiator fan to cycle on and off when idling - there is a sensor that reads the temperature of the coolant at all times and if the coolant gets hotter than a set level the car switches the fan on until the temperature of the coolant goes below the threshold, after which the fan is turned off. There is no need for the fan to run at all times unless it is specifically needed, such as when crawling in traffic on a hot day, but on an open road at usual driving speeds the airflow through the grille at the front of the car is enough to keep the coolant cool enough and the fan is not used.

As others have said, if the car is fitted with Aircon and this is switched on (provided the a/c still actually works that is) the radiator fan will run most of the time, regardless of the temperature of the engine coolant. This is because on models with a/c there are two radiators, one behind the other at the front of the car, the coolant radiator which is the larger one closer to the engine, and the a/c condenser radiator located in front of the coolant radiator, towards the grille side of the car. The a/c must have the condenser being cooled at all times when it is running, so the cooling fan runs all the time, until the a/c is turned off again (provided the a/c is still functional)