A circular disk covered in rubber or plastic with a hole in the center where the edge is sometimes tensioned by a spring that prevents fluid from leaking at the Windshield Washer Fluid Pump. Headlight Washer Pump Grommet. Seals the Headlamp Washer Pump to the reservoir. Washer Fluid Reservoir Mounting Grommet. Washer Fluid Reservoir Seal. Windshield Washer Pump Grommet. Fluid Reservoir Mounting. o - ring. AUXILIARY. Filler neck. Headlight. Plug. Windshield.