Air mass sensor bolt. A Bolt used to mount the engine cooling fan shroud. A threaded rod with a drive head (such as hex, 12 point, torx, etc.) on one end used to secure the HVAC Case to its mounting surface. HVAC Blower Motor Bolt. Mass Air Flow Sensor Bolt. inlet. /SCREW - Service PART Only. Engine Cooling Fan Shroud. HVAC Blower Motor. HVAC Unit Case. Mass Flow Sensor. Included with: Air inlet.