AC Evaporator

This procedure involves removing the dashboard and HVAC housing to replace the AC evaporator core in the 2023 Chevrolet Bolt EUV electric vehicle.

Warnings

Tools required

Parts

• AC Evaporator Core × 1 — Use OEM specification
• Evaporator O-ring Kit × 1 — Use OEM specification
• Expansion Valve O-rings × 1 — Use OEM specification
• AC Line O-rings × 4 — Use OEM specification
• Cabin Air Filter × 1 — Use OEM specification
• PAG Oil (for AC system) × 1 — GM Part No. 88862806 or equivalent
• Dashboard fastener assortment × 1 — Replacement clips as needed

Fluids

• R-1234yf Refrigerant (as specified by AC capacity label)

Preparation

1. Park vehicle on level surface and apply parking brake
2. Ensure high-voltage system is disabled per manufacturer shutdown procedure
3. Disconnect 12V battery negative terminal and wait minimum 2 minutes
4. Recover all AC refrigerant using certified recovery equipment and record quantity removed
5. Remove front seats to provide working space (4 bolts per seat)
6. Disconnect seat electrical connectors and label them
7. Remove center console completely
8. Remove all lower dashboard trim panels on both driver and passenger sides
9. Disconnect and remove steering column (mark position for reassembly)
10. Disconnect all dashboard electrical connectors and label each one
11. Take photographs of routing for all wiring harnesses and vacuum lines

Procedure

1. 1

   Disconnect AC Lines from Evaporator
   Working in the engine compartment, locate the AC line connections at the firewall where they connect to the evaporator. Using a flare nut wrench, carefully disconnect the liquid and suction lines. Immediately cap all open fittings to prevent moisture and debris entry. Inspect the O-rings and discard them.
2. 2

   Remove Instrument Panel
   Remove the instrument panel mounting bolts located at both ends, center support, and upper locations (typically 8-12 bolts total). With an assistant or using dashboard support stands, carefully pull the entire dashboard assembly back and lift it away from the vehicle. Ensure all electrical connectors, HVAC controls, and antenna connections are disconnected before fully removing.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
3. 3

   Remove Cross-Car Beam
   Remove the cross-car support beam mounting bolts that run behind the dashboard. This structural beam must be removed to access the HVAC housing. Note the exact position and orientation of the beam for reinstallation. Keep all fasteners organized.
   Torque spec

   Mounting Bracket Bolts24 Nm (18 lb-ft)
4. 4

   Disconnect Blower Motor
   Disconnect the blower motor electrical connector. Remove the blower motor mounting screws and carefully extract the blower motor assembly from the HVAC housing. Set aside in a clean area.
   Torque spec

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

   Remove HVAC Housing Upper Cover
   Locate and remove all cover screws securing the upper portion of the HVAC housing. Carefully lift the upper cover away, noting any duct connections or clips that must be released. Pay attention to the position of any foam seals or insulation.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
6. 6

   Disconnect Expansion Valve
   Locate the thermal expansion valve (TXV) attached to the evaporator inlet. Remove the expansion valve mounting fasteners and carefully disconnect it from the evaporator. Inspect the TXV for debris or damage. Discard old O-rings and cap all openings immediately.
   ⚠The expansion valve contains small passages that are easily contaminated. Work in a clean environment and cap all openings immediately.
   Torque spec

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

   Remove Evaporator Case
   Remove all evaporator case screws securing the evaporator housing halves together. Carefully separate the case halves, taking note of any duct clips or foam seals. Remove any remaining brackets or clips holding the evaporator core in place.
   Torque spec

   Evaporator Case Screws5 Nm (4 lb-ft)

   Duct Clips3 Nm (2 lb-ft)
8. 8

   Extract Old Evaporator Core
   Carefully lift the old evaporator core out of the housing. Inspect the housing for any debris, leaves, or moisture buildup. Clean the housing thoroughly with a lint-free cloth. Check for any signs of water leaks or mold. Measure and record the amount of PAG oil that drained from the old evaporator.
9. 9

   Install New Evaporator Core
   Add the appropriate amount of fresh PAG oil to the new evaporator core (typically the same amount removed, plus 2-3 oz for system losses). Carefully position the new evaporator core into the housing, ensuring it seats properly in all mounting locations and that the inlet/outlet ports are correctly oriented toward the firewall openings.
   ℹ️Use only the correct PAG oil viscosity specified for R-1234yf systems (typically PAG 46).
10. 10

    Reassemble Evaporator Case
    Install new foam seals if provided with the evaporator kit. Carefully join the evaporator case halves together, ensuring proper alignment. Install and torque all evaporator case screws evenly in a cross-pattern to prevent warping. Reinstall duct clips.
    Torque spec

    Evaporator Case Screws5 Nm (4 lb-ft)

    Duct Clips3 Nm (2 lb-ft)
11. 11

    Install Expansion Valve
    Install new O-rings on the expansion valve, lubricating them lightly with PAG oil. Position the expansion valve on the evaporator inlet and torque the fasteners to specification. Ensure the valve is oriented correctly and the sensing bulb (if external) is properly positioned.
    Torque spec

    Expansion Valve10 Nm (7 lb-ft)
12. 12

    Reinstall HVAC Components
    Reinstall the HVAC housing upper cover with all cover screws torqued to specification. Reinstall the blower motor assembly and torque mounting screws. Reconnect the blower motor electrical connector. Verify all internal HVAC components are secure.
    Torque spec

    Cover Screws11 Nm (8 lb-ft)

    Blower Motor Screws7 Nm (5 lb-ft)
13. 13

    Reinstall Cross-Car Beam and Dashboard
    With an assistant, position and install the cross-car support beam, torquing all mounting bracket bolts to specification. Carefully position the instrument panel back into place, reconnecting all electrical connectors, HVAC controls, and other connections as labeled during disassembly. Install and torque all dashboard mounting bolts.
    Torque spec

    Mounting Bracket Bolts24 Nm (18 lb-ft)

    Mounting Bolts27 Nm (20 lb-ft)
14. 14

    Connect AC Lines
    Install new O-rings on all AC line fittings, lubricating with PAG oil. Connect the liquid and suction lines to the evaporator ports at the firewall. Torque the AC line fittings to specification using a flare nut wrench or crowfoot adapter on a torque wrench.
    ⚠Do not reuse old O-rings. New O-rings must be lubricated with PAG oil before installation to ensure proper seal.
    Torque spec

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

    Vacuum and Recharge AC System
    Reconnect 12V battery. Using certified AC service equipment, evacuate the AC system for minimum 30 minutes to remove all moisture. Perform a vacuum hold test for 15 minutes to verify no leaks exist. If vacuum holds, recharge the system with the correct amount of R-1234yf refrigerant as specified on the underhood label. Add UV dye if desired for future leak detection.
    ⚠System must hold vacuum for at least 15 minutes before charging. Any vacuum loss indicates a leak that must be repaired before adding refrigerant.

Reassembly

1. Reinstall steering column to marked position and torque all fasteners
2. Reinstall all lower dashboard trim panels and ensure all clips are fully seated
3. Reinstall center console with all mounting fasteners
4. Reconnect and reinstall front seats, torquing seat bolts to specification (typically 45 Nm)
5. Reconnect all seat electrical connectors
6. Install new cabin air filter before testing system
7. Verify all dashboard functions, gauges, and warning lights operate correctly

Verification

• Start vehicle and verify no warning lights related to airbags or electrical systems are present
• Turn AC system to maximum cold and highest fan speed
• Verify cold air is produced at all vents within 2-3 minutes of operation
• Check for proper airflow distribution in all modes (floor, panel, defrost, mixed)
• Use refrigerant leak detector to check all AC line connections for leaks
• Verify evaporator drain tube is draining condensate properly after 10 minutes of operation
• Check that AC compressor cycles on and off normally
• Measure vent temperature (should be 38-45°F in recirculation mode at 75°F ambient)
• Verify no unusual odors from vents indicating refrigerant or PAG oil leaks
• Test all dashboard controls, switches, and displays for proper operation
• Perform a final walk-around to ensure all trim panels and components are secure

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