I'm looking into the same issue - frequent running of the fan on my 2005 4/4 (blacktop zetec) when fully warm. I'm not convinced the temp is high enough to require such a lot of "fanning" - gauge reading 105-110 max. Some other posts have suggested this is a "characteristic" of the black top zetec engined 4/4. If so, its a b. nuisance. The ECU, which controls the fan, apparently gets its signal from one of two sensors, one is in the thermostat housing and one in the block, but in the rats nest of cables everywhere, I can't really make these out. I guess its possible a malfunctioning sensor could fool the ecu into running the fan more than needed.
But - I have had a S/S manifold fitted, which gets quite hot, and eliminates the heat shield between exhaust and water rail/tubing. This may well be increasing the temperature of the circulating water. I have no leaks, all hoses are good, and I plan to carry out a full flush just in case.
A Mulfab rad would apparently make the car run cooler, but that is a high cost item and job, so I'm reluctant to even consider that until this issue is sorted out. Another option is zircotec coating of the manifold. But first I need the sensor/ECU issue checking out, which I now think is beyond my limited skills.
Any suggestions, or solutions, would be very welcome! The sensors are not expensive apparently, but it would be helpful to be able to identify them first - anyone with photos?
Nigel
