Last night on the way home running a steady 65 mph on a cool night my temperature gauge started acting funny going from cold to hot and back down repeatedly. When I arrived at home and turned the key off the temperature gauge pegged itself on the hot side although the engine didn't seem to be that hot.. The next day I drove it a few miles it did the same thing. But this time when I got back I could hear coolant gurgling in the radiator . Drove it again a few days later and everything seemed to work as it should... And now a week later it's doing it again???