1000. front. Lower case gasket. PartQualifier: front. A circular disk covered in rubber or plastic with a hole in the center where the edge is sometimes tensioned by a spring that prevents fluid from leaking at the Evaporator Case. HVAC Case Seal. Part included in Evaporator assembly. Air Conditioning (A/C) Evaporator Core. Gasket. HVAC. Packing, Cooler, NO. Included with: Evaporator assembly.