Car revs high and fan running when not over heating
SKODA SUPERB Estate (3T5)

Hi, I have a problem with my car where the revs are staying a little bit high but the fan runs even when the engine is cold. The only way of clearing this problem is by going onto the motorway to give it a run, this will clear the problem then it the problem might return a couple of days, a week or even a month later, it is never the same. Does  anyone have any idea what could be causing this?

Thanks