AC Expansion Valve (TXV)

Remove and replace the AC expansion valve (TXV) in the HVAC system, including recovering and recharging the refrigerant system.

Warnings

Tools required

Parts

• AC Expansion Valve (TXV) × 1 — Use OEM specification
• AC Line O-rings × 4 — Use OEM specification
• R-1234yf Refrigerant × 1 — Use OEM specification
• PAG Oil (for AC system) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and apply parking brake
2. Disconnect 12V battery negative terminal and wait 2 minutes
3. Verify AC system refrigerant type using refrigerant identifier (must be R-1234yf)
4. Run AC recovery machine to fully recover all refrigerant from the system and record amount recovered
5. Remove passenger side lower dashboard trim panels for HVAC access
6. Remove glove box assembly by releasing retaining clips and disconnecting any electrical connectors
7. Disconnect HVAC electrical connectors and label for reassembly

Procedure

1. 1

   Access HVAC module
   Remove mounting screws securing the HVAC module cover on the passenger side. Carefully pull the cover away to expose the evaporator core and expansion valve assembly. The expansion valve is located at the inlet of the evaporator core.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
2. 2

   Disconnect refrigerant lines from expansion valve
   Using a line wrench, carefully disconnect the liquid line and suction line fittings from the expansion valve. Cap or plug the open lines immediately to prevent moisture and debris entry. Inspect the fittings for damage or corrosion.
   ⚠Even after recovery, residual refrigerant may be present. Work in a well-ventilated area and wear safety glasses.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
3. 3

   Remove expansion valve mounting
   Locate the expansion valve mounting bolts securing it to the evaporator inlet. Remove these bolts and carefully extract the expansion valve from its mounting position. Note the orientation and position of any insulation or thermal sensing bulb.
   Torque spec

   Expansion Valve10 Nm (7 lb-ft)
4. 4

   Remove old O-rings and inspect sealing surfaces
   Remove and discard all O-rings from the expansion valve ports and line connections. Inspect the sealing surfaces on the evaporator and refrigerant lines for damage, corrosion, or debris. Clean surfaces with a lint-free cloth if necessary.
   ℹ️Do not use petroleum-based cleaners on AC system components. Use only approved AC system cleaners or isopropyl alcohol.
5. 5

   Prepare new expansion valve
   Remove the new expansion valve from packaging. Install new O-rings on all connection points, lightly coating each O-ring with PAG oil compatible with R-1234yf refrigerant. Ensure O-rings are seated properly in their grooves.
   ℹ️Use only the correct PAG oil viscosity specified for the Bolt EUV AC system. Incorrect oil can cause compressor damage.
6. 6

   Install new expansion valve
   Position the new expansion valve in the correct orientation at the evaporator inlet. If equipped with a thermal sensing bulb, ensure it is positioned exactly as the original. Install and hand-tighten the mounting bolts, then torque to specification.
   Torque spec

   Expansion Valve10 Nm (7 lb-ft)
7. 7

   Reconnect refrigerant lines
   Install new O-rings on the refrigerant line fittings, coating with PAG oil. Connect the liquid line and suction line to the expansion valve. Hand-tighten fittings first, then use a line wrench to torque to specification. Do not overtighten as this can damage the O-rings.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
8. 8

   Reinstall HVAC module cover
   Position the HVAC module cover back into place, ensuring no wires or components are pinched. Install and torque the cover screws to specification. Reconnect all HVAC electrical connectors using your labels.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
9. 9

   Evacuate AC system
   Connect the AC machine to the service ports. Evacuate the system to a deep vacuum (minimum 500 microns) for at least 30 minutes. Monitor for vacuum decay to verify there are no leaks. System should hold vacuum for 10 minutes without significant pressure rise.
   ⚠If system will not hold vacuum, locate and repair leak before proceeding with recharge.
10. 10

    Recharge AC system
    Recharge the system with R-1234yf refrigerant to the amount recorded during recovery (or factory specification if significantly different). Add any additional PAG oil as needed to compensate for oil lost during component removal. Close service valves when complete.
    ℹ️Factory refrigerant capacity is approximately 650-750 grams. Verify exact specification on vehicle underhood label.

Reassembly

1. Reinstall glove box assembly and ensure all clips are fully engaged
2. Reinstall passenger side lower dashboard trim panels
3. Reconnect 12V battery negative terminal
4. Start vehicle and allow HVAC system to initialize

Verification

• Turn on AC system to maximum cooling and high fan speed
• Verify compressor engages and runs smoothly without unusual noise
• Check center vent temperature reaches 40-45°F within 5 minutes at ambient temperature of 75-80°F
• Inspect all refrigerant line connections for signs of oil leakage indicating refrigerant loss
• Verify even cooling across all vents and proper airflow distribution
• Use electronic leak detector to verify no refrigerant leaks at expansion valve or line connections
• Test HVAC controls for proper operation in all modes (heat, cool, defrost)

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