Abstract: An electromagnetically controlled clutch is used to engage and disengage the cooling fan of a water cooled motor vehicle engine. The clutch and fan assembly in the form of an adapter kit may be attached to the existing fan mountings normally located on the water pump pulley assembly. The adapter kit includes an extender cylinder which bolts to the existing fan mountings. Bearings are provided inside this cylinder for rotationally free mounting a fan mounting hub supported on a shaft, which is free to rotate within the extender hub. An annular armature is spaced from the pulley assembly and supported around the hub by leaf springs, attached at one end to the hub and at the other end through rigid extender arms to the armature.