Thermostat

Water cooled motor has thermostat for the convenience in warming up scenery to stop cold cooling liquid circulation in the motor water gallery. The cooling liquid in the motor is warmed gradually until around 80 Celsius degree, water thermostat opens to let the outside liquid into the motor and the normal liquid circulation including the radiator starts.
On the other hand how about air-cooled motor like ancient VW Beetle?
Deeper investigations revealed that even air-cooled one has thermostat also that looks having nothing to do with over-cooling!
At the very beginning stage thermostat in air-cooled motor shuts the intake door to invite cooling air from the fan to prevent the over cooling in the first idle stage. After that the heat on the #1 & #4 cylinder expands the bi-metal thermostat, then the doors are opened mechanically.
So the malfunctions on this important device cause over cooling in the first idling when it left opened and over heating when left closed. The thermostat plays a greatest part of motor operations, unmovable truth to be payed attentions more on.
The thermostat in air-cooled motor may be an indispensable and a surprising loophole equipment on earth.