Fan Clutch Spanner Wrench

spanner wrench
One of the most useful tools for engine repair. Not currently manufactured.

fan clutch
A viscous-fluid clutch that controls how fast an engine fan rotates to help cool an engine.
A fan clutch is a thermostatic device that exists as an integral component of certain automotive cooling systems.
A Viscous (fluid) drive coupling device connected to the center of the fan to permit variable engine fan speeds in relation to engine speeds. The Clutch engages and disengages the fan according to the engine temperature through a thermostat