Left.NORTH AMERICA BUILT. Right.NORTH AMERICA BUILT. Side support nut. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Engine Coolant Expansion Tank. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Radiator Support Side Panel. Nut that secures the Radiator Shutter Assembly. Radiator Mount Nut. Flange. grommet. Tank. Engine Coolant. Mount bracket. Radiator Support Side Panel. Shutter Assembly.