Engine fan on when standing still and low mpg 2002 yaris

[andqe]

So, I bought a pretty old 2002 yaris with 60k miles. I checked out everthing, the drive oils etc.

But I have since found out that the engine cooling fan comes on while sitting still in just 68d outside, in comparison my friends clio fan has only comes on rarely when it is very hot.

The fan rarely runs when the car is driving but surely such a small car shouldnt require cooling when standing still in these fairly low temperatures.

Mpg seems to hang around 30 which seems low even around the city, so this makes me wonder whether these two things are related and are there any checks to diagnose any problem?

Thanks.

[willygoodness]

air-con fan?

[andqe]

Nope, only ever used the aircon when I tested it before buying it.
I am more of a windows down person, myself.

[CTScott]

It is possible that the coolant temperature sensor (mounted to the bottom of the radiator) is bad. The other thing to check is to follow the wiring to the radiator fan to make sure that the prior owner didn't hard wire it to always be on.

[andqe]

Thanks for the reply Scott.
The engine fan isn't always on it turns on periodically. I don't think the sensor is bad as it turns on when the engine is hot and the engine seems to be (the front right headlight has faded from clear to almost yellow on the top part of it.). Unfortunately the yaris doesn't have an engine temp light. Does coolant always have to be flowing around the engine, how would I check this is ok? The fill level is slap bam in the middle and there is no leakage.

[CTScott]

Thanks for the reply Scott.
The engine fan isn't always on it turns on periodically. I don't think the sensor is bad as it turns on when the engine is hot and the engine seems to be (the front right headlight has faded from clear to almost yellow on the top part of it.). Unfortunately the yaris doesn't have an engine temp light. Does coolant always have to be flowing around the engine, how would I check this is ok? The fill level is slap bam in the middle and there is no leakage.

The water pump runs constantly to move water, by the thermostat regulates flow through the radiator.

Typically with the engine running, once it is warmed up, the fan will come on more when stationary than while moving, as the moving air has the same effect as the fan.