S 500 Coupe (140.070) V8-5.0L (119.980) (1997)
Expansion Block/Orifice Tube: Description and Operation
Refrigerant Injection Valve (107) [arrow indicates direction of flow]
Instead of the familiar expansion valve, the refrigerant injection valve sprays refrigerant into the pressure line to the rear air conditioning evaporator. The
pressure line is insulated to reduce refrigeration losses.