Fixed Orifice Tube
WARNING: This page is about a different car, the 1996 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
Fixed orifice tube is located in the liquid line, between the condenser and the evaporator. The tube creates a restriction in the high side pressure line, metering liquid refrigerant into the evaporator core. A filter screen at each end of the tube prevents the tube's orifice from clogging. "O" rings prevent liquid refrigerant from by-passing the tube.