420MM Fan Blade. This fan blade is driven by the serpentine belt, engaged by the fan clutch. If you have bad motor mounts (engine mounts), it is fairly common for the blades on the fan to make contact with the radiator or radiator shroud, which makes it extremely noisy and essentially the fan will break into many pieces. Be sure to get a new fan clutch, while you are replacing this as well as check your engine motor mounts for any damage or need of replacement!