Thanks to all for the replies. I will pull the radiator out to give it a good flushing. Which way does it normally flow on a 4x4. I also have a bottle of "Radiator flush and clean" which you are supposed to put in the system and run for 20mins to an hour then flush out again. Meant to remove sludge and scale but was a little worried that it might loosen up something and then circulate it to a more critical place and get stuck i.e, the pump. May also have to look at a new pump from the U.K. any more sugggestions of the best place for purchase. Bit scared to run it for too long as it sounds like runnning dry. Thanks again David.