agree with outback1,
this sounds like a viscous fan bearing on its way out. remove fan belt and check if there is any side movement (wobble) in the fan itself. if there is, replacement of the bearing is fairly straight forward. a replacement bearing is not that costly if you get an equivalent to the LR part (make sure its a japanese, german, etc... not chinese part) ...should be around $50 mark.
a good guide can be found at www.discovery2.co.uk

