Bimetal coil assembly for fan drive

A viscous fan clutch comprising:

• a housing having a plurality of first concentric ribs;
• a rotor rotatably disposed in the housing, the rotor having a plurality of second concentric ribs that are juxtaposed with the first concentric ribs, the rotor and the housing cooperating to form a working chamber;
• a fluid reservoir that is coupled in fluid communication with a radially inner side of the working chamber;
• a valve coupled to the housing, the valve including a valve element that is rotatably disposed in the housing and movable between a first valve element position, which inhibits fluid communication from the fluid reservoir into the working chamber, and a second valve element position that permits fluid communication from the fluid reservoir to the working chamber;
• a bimetal coil having a first end, which is rotatably coupled to the valve element, and a second end that is radially outward of the first end;
• an adjustable retainer member that is movable about a rotational axis of the rotor relative to the housing through a predetermined angle, the adjustable retainer member defining a first slotted mounting aperture and a channel into which the second end of the bimetal coil is received;
• and
• a first threaded fastener received through the first slotted mounting aperture and threadably coupled to the housing.