Astro 78200 Fan Clutch Service Set for Mercedes-Benz and BMW Removal of lock nuts on thermo Viscous fans found on Mercedes-Benz, BMW, Ford and many other vehicles Allows the technician to hold the water pump pulley in place while loosening the radiator fan for removal of the visco-coupling on the cooling fan Special open-ended spanner to allow removal and replacement of the radiator fan hub  The three-in-one design allows servicing of three separate areas of repair (which all require a specialty tool due to their confined locations) Blow molded case for easy storage and transport