1998 ls 400 temp gauge go to hot after running 10 minutes . not losing cabin heat no smell of coolant . replaced thermostat did not help .

 

from your other post here, you are already looking at the cluster sensor which is the right path.

but are you sure you do not have any air in the coolant? has there been any recent coolant related work done to the car?

 

i believe i found my issue took belt weight of water pump belt and found movement in the pump