Countermeasure

The consultation with SUBARU Customer Center about the function of the thermo-unit on the place #4 cylinder proved the sensor does not play a part of electric cooling fan control. It is used only for the mater control but any other functions.
Though thermo-unit is ordered already, it's function has nothing to do with the strange phenomena experienced yesterday, continuously lasted electric fan function?

First of all, I must try to remove bubbles from cooling liquid circuitry with desperate efforts. I cannot deny the possibility of past bubble remained for long time of period since LLC replacement last year and the remained bubble between engine block and heater core had moved to inconvenient portion of the cylinder water gallery and only the coolant temperature around the sensor comes up?
Anyway this persistent foam straying to the circuitry must be thoroughly removed by hook or crook.

Thermo-unit for heat gauge operation only. 21203 AA030
Coolant sensor for EGI fuel mixture control including electric cooling fan control. 22630 AA041