yah with a radiator working properly, the proper coolant mixture and ur cooling system working correctly and not leaking fluid somewhere u shouldnt be experiencing that problem, do u ever have to add fluid to it? or does the needle just like to move around? id say replace ur thermostat do half and half coolant and water and check all ur hoses and radiator for leaks, also check the old coolant for large amounts of oil to see if u have a leak somewhere in ur engine, if ur not losing coolant newhere and arent putting in more water then just replace the coolant and the thermostat and leave it alone see if it fixes ur problem