#2. Mount bracket bolt. PartQualifier: #2. A threaded rod with a drive head (such as hex, 12 point, torx, etc) on one end used to secure the Engine Coolant Outlet Housing or related components. Alternator Bracket Bolt. Engine Coolant Pipe Bolt. Flange. Air inlet case. Alternator Bracket. Connector. Engine Coolant Outlet Housing. Timing cover mount. Water Outlet retainer.