AC Orifice Tube

This procedure covers the replacement of the AC orifice tube on a 2024 Rivian EDV 500, including refrigerant recovery, component removal, and system recharge.

Warnings

Tools required

Parts

• AC orifice tube × 1 — Use OEM specification
• O-ring kit for AC lines × 1 — Use OEM specification
• PAG oil (compatible with R-1234yf) × 1 — Use OEM specification
• UV dye (if not pre-charged in system) × 1 — Use OEM specification

Fluids

• R-1234yf refrigerant

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn off vehicle and remove key fob from cabin area
3. Allow AC system to stabilize to ambient temperature (minimum 30 minutes after last operation)
4. Verify you have EPA 609-certified technician certification for refrigerant handling
5. Connect R-1234yf recovery machine and verify machine is functioning properly
6. Document pre-service refrigerant charge amount for proper refill
7. Take photos of AC line routing and connections for reference during reassembly
8. Prepare clean workspace with lint-free cloths for handling AC components

Procedure

1. 1

   Recover refrigerant from AC system
   Connect recovery machine to high and low side service ports located in the front motor bay area. Follow recovery machine instructions to completely evacuate all R-1234yf refrigerant from the system. Record the amount recovered for comparison to system capacity. Wait for system pressure to equalize to atmospheric pressure before proceeding.
2. 2

   Access front motor bay AC components
   Open the front trunk (frunk) and remove the access panel covering the AC lines and thermal management components. Remove plastic fasteners and any trim panels necessary to access the liquid line between the condenser and evaporator. The orifice tube is typically located in the liquid line near the firewall or at the evaporator inlet.
3. 3

   Locate the orifice tube position
   Identify the liquid line connection where the orifice tube is installed. On the EDV 500, this is typically at the evaporator inlet where the liquid line enters the HVAC module. Look for a larger diameter section or specific fitting that houses the orifice tube. The tube will be upstream of the evaporator and downstream of the condenser.
4. 4

   Disconnect liquid line at orifice tube location
   Using a flare nut wrench to prevent line damage, carefully loosen and disconnect the AC line fitting at the orifice tube location. Have shop towels ready to capture any residual refrigerant oil. Cap the open condenser-side line immediately to prevent moisture and contamination entry. Inspect the connection threads for damage.
5. 5

   Remove the orifice tube
   Using an orifice tube removal tool or pick set, carefully extract the orifice tube from the line or evaporator inlet. The tube may be tight due to O-ring sealing. Do not use excessive force that could damage the tube housing bore. If the tube breaks during removal, use a specialized extraction tool to remove all fragments. Inspect the removed tube for metal debris or blockage which indicates compressor failure.
6. 6

   Inspect system for contamination
   Examine the removed orifice tube screen for metal particles, debris, or sludge. Check the color and condition of refrigerant oil residue. Dark oil or metallic particles indicate compressor damage requiring additional service. If contamination is present, the AC system must be flushed and the compressor inspected or replaced before proceeding.
7. 7

   Prepare new orifice tube
   Remove the new orifice tube from packaging. Verify it matches the OEM specification for screen color and size designation. Lightly coat the O-rings with fresh PAG oil compatible with R-1234yf refrigerant. Do not use petroleum-based lubricants. Ensure the tube is clean and free from any manufacturing debris.
8. 8

   Install new orifice tube
   Insert the new orifice tube into the liquid line or evaporator inlet, ensuring proper orientation with the shorter end toward the evaporator. Push firmly until the tube is fully seated against the internal stop. The tube should sit flush with minimal resistance. Verify O-rings are not pinched or damaged during installation.
9. 9

   Replace O-rings and reconnect AC line
   Install new O-rings on the AC line fitting, lubricating with PAG oil. Remove the cap from the condenser line and immediately reconnect the fitting to the evaporator inlet housing. Hand-tighten first to ensure proper thread engagement, then use a torque wrench and flare nut wrench to tighten to specification. Since no torque values are provided in database, tighten to manufacturer specification found in service manual.
10. 10

    Add refrigerant oil
    Add the appropriate amount of PAG oil to the AC system to replace oil lost during refrigerant recovery and component service. Typically 1-2 ounces of oil should be added when replacing the orifice tube. Consult the service manual for exact oil capacity. Add oil through the low-side service port or compressor fill port as specified.
11. 11

    Evacuate AC system
    Connect vacuum pump to the AC system service ports. Evacuate the system to at least 29 inches of mercury vacuum for a minimum of 45 minutes. This removes all air and moisture from the system. Monitor the vacuum gauge after pump shutoff - vacuum should hold steady for 10 minutes, confirming no leaks are present.
12. 12

    Recharge AC system with R-1234yf
    Using the recovery/recharge machine, charge the system with the exact amount of R-1234yf refrigerant specified on the vehicle underhood label or service manual (typically based on the amount recovered plus any loss). Charge through the low-side service port with the system off, then start the vehicle and HVAC system to complete charging. Monitor pressures during charging process.
13. 13

    Perform leak test
    With the system fully charged, use a R-1234yf electronic leak detector to check all connections, particularly the orifice tube installation point. If UV dye was added, use UV light to inspect for leaks. Check both high and low side pressures with manifold gauges to confirm proper system operation and no pressure loss.
14. 14

    Verify AC system operation
    Start the vehicle and set HVAC controls to maximum cooling with recirculation mode on. Allow system to run for 10 minutes. Monitor discharge air temperature at center vents - should reach 38-45°F depending on ambient conditions. Verify compressor clutch engagement if equipped with variable displacement compressor, or verify smooth operation of electric compressor. Check for abnormal noises or vibrations.

Reassembly

1. Reinstall all trim panels and access covers removed from front motor bay
2. Verify all fasteners are properly secured and no tools or parts are left in motor bay
3. Close and secure the front trunk (frunk)
4. Clean any refrigerant oil residue from exterior surfaces

Verification

• Confirm AC discharge temperature is within specification (38-45°F at center vents)
• Verify no refrigerant leaks detected at orifice tube location or any service points
• Check that system high and low side pressures are within normal operating range
• Listen for proper compressor operation with no unusual noises
• Verify airflow is strong and consistent from all vents
• Confirm no warning lights or AC-related fault codes in vehicle system
• Test AC operation in all blower speeds and temperature settings
• Document refrigerant charge amount matches system specification

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