GM 19332847
Expansion Valve

The first step when replacing the A/C Expansion Valve of the second design is to check for leaks using the Halogen Leak Detector (J 39400-A). Refrigerant recovery must be performed first followed by the removal of evaporator outlet hose and liquid line retainer plate nut from A/C Expansion Valve. The work area should remain clean while only using new tools to prevent contamination of O-ring sealing surfaces. Take out the evaporator outlet hose and liquid line from the A/C Expansion Valve before disposing the sealing washers. Protective caps should be installed on both the evaporator outlet hose and liquid line to stop contamination during the process. Remove the A/C Expansion Valve bolts from the backing plate before extracting the A/C Expansion Valve as well as backing plate from the vehicle while discarding the O-rings from the evaporator pipes and applying protective caps for contamination prevention. The installation process demands clean and dry and free of lint junctions on the evaporator pipes before installing new O-rings. Place the A/C Expansion Valve into position and its matching backing plate onto the evaporator pipes before screwing A/C Expansion Valve bolts until they reach 8 N.m torques (71 lb in). The next step requires removal of protective caps from the liquid line and evaporator outlet hose before adding new seal washers to prepare for attachment of these parts to the A/C Expansion Valve while securing them with a retainer plate nut at 20 N.m (15 lb ft). The A/C system needs evacuation before charging while the affected A/C joints need testing for leaks through use of the Halogen Leak Detector (J 39400-A).

The process for A/C Expansion Valve (TXV) replacement in the first design begins with leak testing through the use of the Halogen Leak Detector (J 39400-A). The first step involves refrigerant recovery then evaporator outlet hose nut detachment from the A/C Expansion Valve to prevent dirt from affecting the O-ring sealing areas. The work area and tools need complete cleaning with non-petroleum based solvents while using lint-free cloths. Place a protective cap on the A/C Expansion Valve to stop contamination before breaking the evaporator outlet hose free from the A/C Expansion Valve. Drop the liquid line nut from the A/C Expansion Valve and disconnect the liquid line before capping both components to stop contamination. Disconnect the refrigerant low temperature sensor from the engine harness before taking out the backing plate and A/C Expansion Valve by removing its bolts. The old O-rings from evaporator pipes should be discarded while protective caps keep the pipes clean. Before installing new O-rings on evaporator pipes always check that the seam areas are free of moisture and debris. Fit the A/C Expansion Valve between its backing plate while also attaching these components to the evaporator pipes and torque the A/C Expansion Valve bolts to 80 lb in (9 N.m). Use a new seal washer then screw the liquid line to the A/C Expansion Valve before tightening the nut to 16 N.m (12 lb ft). The installer should complete this step on the evaporator outlet hose by using a new seal washer before securing the nut to 16 N.m (12 lb ft). The last procedure involves connecting the refrigerant low temperature sensor back to the engine harness then evacuating and charging the A/C system before using the Halogen Leak Detector (J 39400-A) to check for leaks in the affected A/C joints.