discovery td5 problem

been to look at a 2000 x reg gs today,looks tidy for its age few jobs to do,its had its ace blanked of,one prob with coolent side when its started the coolen in the header tank diapears,truck on gauge is at norm 1/2 why up,took it for a run for few miles got back went back under bonnet,and coolent eventuly started to fill tank back up,top hose red hot and hard,bottom hose cold,any advise,many thanks

Top hose will always be hotter than the bottom but should not be rock hard. This normally points at a leaking head gasket pressurising the cooling system. If you get chance run the engine until normal warm with the radiator cap off. If there is evidence of bubbles in the coolant tank its defo a head gasket problem.

whilst running at norm temp all the water in header tank had gone,it was when you switch it of water starts to come back,into tank,the chap had had it running before i got their,lifted bonnet and header tank was empty,he started to undo cap and then it all started hissing and the water coming back into tank,somthing not right and he wants 3500 for it