Loose plug probably. 
Mine comes on every few days.... I think its because the header tank level is only 'just' enough to stop the sensor (put too much more coolant in and it blows it out anyway) so sharply pulling away or parking on hills seems to make the light come on.
And I hope the cambelt isn't slipping, as thats what drives the waterpump lol.
Mine comes on every few days.... I think its because the header tank level is only 'just' enough to stop the sensor (put too much more coolant in and it blows it out anyway) so sharply pulling away or parking on hills seems to make the light come on.And I hope the cambelt isn't slipping, as thats what drives the waterpump lol.