This specification establishes the minimum requirements for the coaxial tube of an internal heat exchanger (IHX) assembly to be used in R134a, GMW5038 and R1234yf Air Conditioning (A/C) systems.

Supplier qualification must be demonstrated for the tube design of each unique IHX profile before the supplier may bid on IHX business. To obtain qualification, the supplier's IHX tube design must meet all requirements of this specification and must be approved by the General Motors Bill of Material (BOM) Family Owner (BFO).

This specification does not include the IHX validation requirements for: brazed/welded fittings, access ports, etc., (covered in GMW15787), Air Conditioning Refrigerant System Connections (covered in GMW15787), or seal washers (covered in GMW15779). In addition, this specification does not include the validation requirements for larger assemblies containing an IHX: IHX production assembly parts shall be in accordance with metallic refrigerant lines GMW15773, and lines containing elastomeric hose, or coupled hose assemblies GMW14319.

Mission/Theme. The intent of this specification is to define the thermodynamic performance requirements for coaxial tube internal heat exchangers for use with R134a and R1234yf refrigerant.

Classification. Not applicable.