AC Expansion Valve (TXV)

Replace the AC expansion valve (TXV) on a 2017 Maserati Levante 3.0L V6 Twin Turbo, requiring refrigerant recovery, valve replacement, and system recharge.

Warnings

Tools required

Parts

• AC Expansion Valve (TXV) × 1 — Use OEM specification
• AC line O-rings (assorted sizes) × 1 — Use OEM specification
• PAG 46 compressor oil × 1 — 60-90ml for line replacement
• R-134a refrigerant × 1 — Approximately 850g total system capacity
• UV dye (if not pre-charged) × 1 — Optional for leak detection

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine and AC system to cool completely (minimum 2 hours)
3. Disconnect negative battery terminal and wait 5 minutes for system discharge
4. Verify AC system has not been recently opened to atmosphere (check for service history)
5. Position AC recovery machine and connect manifold gauges to service ports
6. Record static system pressure before recovery for diagnostic reference

Procedure

1. 1

   Recover refrigerant from AC system
   Connect recovery machine to both high and low side service ports. Follow machine instructions to completely recover all refrigerant from the system. Record the amount recovered for comparison to specification (approximately 850g total). Allow system to stabilize at vacuum to verify complete recovery. Print recovery receipt if machine is equipped for documentation.
2. 2

   Access evaporator housing
   Remove lower glove box assembly by pressing side tabs inward and lowering completely. Remove right side lower dash panel using trim tools to release clips. Disconnect any electrical connectors for courtesy lights or sensors. This provides access to the evaporator housing on the passenger side firewall area.
3. 3

   Remove blower motor assembly
   Disconnect blower motor electrical connector. Remove the three mounting screws securing the blower motor to the evaporator housing. Carefully pull blower motor assembly outward to clear housing. Set aside in clean area.
   Torque spec

   Blower Motor Screws7 Nm (5 lb-ft)
4. 4

   Remove evaporator housing cover
   Locate and remove all cover screws securing the evaporator housing access cover (typically 4-6 screws). Carefully separate the cover from the housing, noting the position of any sealing foam or gaskets. The expansion valve will now be visible attached to the evaporator inlet.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
5. 5

   Disconnect refrigerant lines from expansion valve
   Using appropriate wrenches, disconnect the liquid line (smaller diameter) and suction line from the expansion valve body. Immediately cap all open ports with plugs or clean tape to prevent moisture and debris entry. Inspect old O-rings for damage and discard. Note orientation of thermal sensing bulb if attached.
   ⚠Residual refrigerant may still be present in lines. Work in well-ventilated area.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
6. 6

   Remove old expansion valve
   Remove the mounting bolts or clips securing the expansion valve to the evaporator inlet tube (typically 2 bolts). If equipped with a thermal sensing bulb, carefully detach it from the evaporator outlet tube, noting exact placement position. Remove the old expansion valve and inspect the evaporator inlet for debris or damage.
   Torque spec

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

   Install new expansion valve
   Verify the new expansion valve matches the original configuration. Lubricate new O-rings with fresh PAG 46 oil and install on expansion valve body. Position the new valve onto the evaporator inlet, ensuring proper orientation of inlet/outlet ports. Install mounting hardware and torque to specification. If equipped, attach thermal sensing bulb to evaporator outlet in exact original position (typically 6 o'clock orientation).
   Torque spec

   Expansion Valve10 Nm (7 lb-ft)
8. 8

   Reconnect refrigerant lines
   Install new PAG oil-lubricated O-rings on both refrigerant line fittings. Add 30ml of PAG 46 oil to the liquid line connection to replace oil lost during service. Connect both lines to the new expansion valve hand-tight first, then torque to specification using backup wrench on valve body to prevent rotation.
   ℹ️Cross-threading aluminum AC fittings is common. Thread carefully by hand first to ensure proper engagement.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
9. 9

   Reinstall evaporator housing cover
   Clean mating surfaces of housing and cover. Replace any damaged sealing foam. Position cover onto housing and install all screws. Torque screws in a cross-pattern to ensure even sealing.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
10. 10

    Reinstall blower motor
    Position blower motor assembly into housing opening, ensuring fan clears housing interior. Install mounting screws and torque to specification. Reconnect electrical connector and verify connector lock engages.
    Torque spec

    Blower Motor Screws7 Nm (5 lb-ft)
11. 11

    Evacuate AC system
    Connect vacuum pump to AC system via manifold gauges. Evacuate system to 500 microns or lower for minimum 45 minutes. Isolate system and observe vacuum hold for 15 minutes - vacuum should not rise more than 100 microns indicating no leaks. If vacuum does not hold, locate and repair leak before proceeding.
    ⚠Inadequate evacuation will leave moisture in system causing compressor failure and poor performance.
12. 12

    Recharge AC system
    Using recovery/recharge machine or graduated charging cylinder, add refrigerant to system. Total system capacity is approximately 850g (verify on underhood label). Charge liquid side with engine off until 80% full, then start engine with AC on MAX and complete charge through low side. Monitor pressures throughout charging process.
13. 13

    Reinstall interior panels
    Reconnect all electrical connectors for lights and sensors. Install right side lower dash panel ensuring all clips engage properly. Reinstall glove box assembly by aligning mounting tabs and pressing upward until locked. Reconnect negative battery terminal.

Reassembly

1. Verify all interior panels are properly secured with no rattles
2. Ensure all refrigerant line connections are tight and properly torqued
3. Confirm blower motor operates at all speed settings before closing panels

Verification

• Start engine and set AC to MAX cold with fan on high
• Allow system to run for 10 minutes and verify center vent temperature reaches 38-45°F (3-7°C)
• Check low side pressure: should be 25-35 PSI at idle with 75-85°F ambient
• Check high side pressure: should be 180-250 PSI at idle with 75-85°F ambient
• Inspect all connections with UV light or electronic leak detector for leaks
• Verify evaporator outlet line (larger line) shows condensation indicating proper valve operation
• Test AC operation through full temperature range and all fan speeds
• Monitor system for 24 hours and recheck pressures to ensure no refrigerant loss

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