1966 GMC PB25 Series Engine: 4.1L L6; Standard Rotation|Optional Non-Thermal Fan Clutch;. Engine Cooling Fan Clutch. Standard or Reverse Rotation Non-Thermal Fan Clutch. Fan Clutch /Non-Thermal. IMPORTANT: To confirm that this part fits your vehicle, enter your vehicles Year, Make, Model, Trim and Engine in the Compatibility Table.
