how can i fix my tempture guage needle and water warning light?

my 1.2 1998 renault clios tempreture guage needle keeps going into the red but is not overheating also the water warning light comes on after about 10 mins driving it the head gasket isnt gone the thermostat has been replaced and also there is no airlock in the water system and finaly it is not losing water can anybody please tell me whats wrong ?