I first posted this problem in September in the Citroen Xsara Picasso forum as I have been a member there for a few years and couldn't seem to be able to post here. Unfortunately I have had no commenta at all, possibly due to it being in the wrong forum. Anyhow, I've registered for the C3 forum as well now so here goes. I have, from new, a C3 Desire 07 plate, 1.4 petrol, 60000 mls and regularly serviced by main dealer. My radiator fan very rarely comes on except occasionally when I'm in traffic congestion on a hot day. However, for the last few weeks it has been coming on quite often but more when I am moving rather than when stationary in a jam. Some times, for instance, I can hear it when approaching a traffic island but it turns off as I slow down. This is also an intermittent thing as some days it doesn't come on at all. My journeys are often no more than 20 miles and I get no warning of any kind that the engine may be overheating. There is no temperature gauge on the dash on this model. Coolant level in expansion tank is ok but I do sometimes have to top it up from min to max every 2 or 3 months (have been doing this for a few years now). I'm wondering if it could be a fault with the temperature sensor and/or thermostat and if so how easy is it to change them and any guidance as to where they are under the bonnet would help. Any advice would be welcome. Thanks Drakes