if the fan makes noise then it needs replaced. it is an tsb also. i can;t rememnber the number. i replace my hydraulic pump actuator and mine over heats at 3/4 hot and then rapid cools to 1/2 mark everytime i start it and then doesn't over heat after that. i think my fan needs replaced. i think it is around $400 for just the fan.
If you hear the fan running then it's OK. If you are loosing coolant mine was doing the same thing. After replacing the thermostat I found out that the coolant tanks on the LS are prone to hairline cracking. The system is pressurized and that's what it turned out to be.