In a rotary engine, the rotors are cooled by oil from the lubricating system. Each housing, however, is water-cooled, and there are additives in the coolant to protect the housing alloys from corrosion.
The water pump takes coolant from a bottom radiator tank and pushes it through waterjackets in the housings, towards the rear of the engine.
The chamber is surrounded by coolant passages.
Inside the housing is hollow, and it forms a water-jacket.
A pulley on the end of the eccentric shaft drives the water pump and fan.
In the rear housing, the coolant reverses direction and returns to the front of the engine.
It passes a thermostat. As in a piston engine, it is closed when the engine is cold but opens as it warms up.
The rotary engine has an overflow system much like that of a piston engine. As pressure builds up, coolant expands into an overflow tank. As it cools, pressure drops and it returns to the radiator.
A viscous hub links fan speed with engine temperature.
