Horrible thermostat to change. If it is staying at half gauge even when car is first started, then you probably have a wiring or thermistor problem. Not reading right temp. Could be an air pocket in the cooling system, very difficult system to bleed. I use a vacuum tool to place the system in negative pressure and then fill. DO a resistance check on the coolant temp sensor and see if it is within range for the temp.
The sound is probably a wheel bearing. THe loading and unloading as you turn suggest as much. Possibly could be a seperated tread but leaning towards the wheel bearing.