GM Astro/Safari 1985-1996 Repair Guide

Orifice (Expansion) Tube

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See Figures 1 and 2



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Fig. Fig. 1: Orifice tube assembly



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Fig. Fig. 2: Air conditioning system component schematic

The orifice tube is a plastic assembly containing a fixed diameter tube with a mesh filter screen at either end. The tube is located between the condenser outlet and the evaporator inlet tube. The tube acts as a restriction to the high pressure liquid refrigerant in the liquid line, metering the flow of refrigerant to the evaporator.

REMOVAL & INSTALLATION



  1. Discharge the air conditioning system as outlined in General Information & Maintenance . The system should be discharged by a qualified technician with proper recovery equipment. It is illegal to discharge refrigerant into the atmosphere and you may need a permit to purchase new refrigerant. If you do not possess the proper equipment, training and permits to perform refrigerant recovery, allow a repair shop to do that step for you.
  2.  
  3. Disconnect the liquid line at the evaporator inlet and remove the orifice tube from the inlet pipe.
  4.  

If the tube will not dislodge from the inlet pipe, heat the pipe with a hair dryer to loosen the orifice tube. Use an orifice tube removing tool or a needle nose pliers if one is not available. Be careful not to break off the tube inside the inlet pipe.

  1. Flush the entire system to remove any dirt or foreign materials.
  2.  
  3. Remove and replace the accumulator if the orifice tube is clogged with any foreign material.
  4.  

The new tube will clog up if the system is not flushed and an accumulator is not replaced.

To install:
  1. Install the orifice tube into the evaporator inlet pipe with the shorter screen end inserted first.
  2.  
  3. Reconnect the liquid line to the inlet pipe.
  4.  
  5. Evacuate and recharge the air conditioning system as outlined in General Information & Maintenance .
  6.  

 
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