Expansion Valve: Service and Repair

THERMAL EXPANSION VALVE (TXV)

REMOVAL

IMPORTANT: Verifying the purity of the refrigerant with a purity identifier before recovery is recommended.

1. Recover refrigerant using an approved refrigerant recovery system. Measure the amount of oil lost during recovery and record.

CAUTION: DO NOT REMOVE HOSES OR LINES BEFORE SYSTEM IS FULLY DISCHARGED.

NOTE: When removing the TXV, keep dirt and foreign material from getting on or into the O-ring sealing surfaces. Clean tools and a clean work area are important for proper service. The TXV seal area should be cleaned before any repairs are performed. The parts must be kept clean at all times and any parts to be assembled should be cleaned with a non-petroleum based solvent and dried with air. Use only lint free cloths to wipe parts. Do not allow solvent to enter evaporator or hoses.




2. Remove suction hose to TXV nut and remove suction hose.
3. Install shipping cap to end of suction hose to prevent contamination to system.




4. Remove liquid line to TXV nut and liquid line.
5. Install shipping cap to end of liquid line to prevent contamination to system




6. Disconnect TXV thermistor from engine harness.




7. Remove TXV to backing plate attachment bolts and remove TXV and backing plate.
8. Remove O-ring from evaporator pipes and cap pipes to prevent system contamination.

INSTALLATION

NOTE: Use only lint free cloths to wipe parts. Do not allow solvent to enter evaporator or hoses.

1. Remove evaporator pipe caps and insure seal areas are clean, dry and lint free.

NOTE: Use only R-12 refrigerant oil (mineral) to lubricate O-rings. Use of R-134a PAG oil will cause premature corrosion of fitting joints.

2. Install new O-rings to evaporator lubricating with mineral oil.
3. Remove shipping caps and install TXV to evaporator pipes with backing plate and bolts.

Torque:
TXV Backing Plate Bolts: 9 N.m (80 in. lbs.)




4. Remove protective cap from liquid line, install new seal washer and install liquid line to TXV with nut.

Torque:
Seal Washer Liquid Line to TXV: 16 N.m (12 ft. lbs.)




5. Remove protective cap from suction line, install new seal washer and install suction line to TXV with nut.

Torque:
Seal Washer Suction Line to TXV: 16 N.m (12 ft. lbs.)




6. Connect TXV thermistor to engine harness.
7. Evacuate, charge, and leak check the A/C system.