AC Orifice Tube

This procedure covers the replacement of the AC orifice tube in a 2023 Rivian EDV 500, requiring recovery and recharge of the AC refrigerant system.

Warnings

Tools required

Parts

• AC orifice tube with screens × 1 — Use OEM Rivian specification
• AC line O-rings × 4 — Use OEM specification
• R-1234yf refrigerant × 1 — Approximately 2.5 lbs
• PAG oil for R-1234yf systems × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect 12V battery negative terminal and wait 2 minutes for system capacitors to discharge
3. Verify AC system has not been recently operated (allow 30 minutes cool-down if necessary)
4. Locate the orifice tube housing in the liquid line near the firewall on passenger side
5. Remove any necessary underbody panels or splash shields for access to AC lines
6. Clean the area around AC line connections to prevent contamination

Procedure

1. 1

   Recover AC refrigerant
   Connect the R-1234yf recovery machine to the AC service ports. Follow machine manufacturer procedures to completely recover all refrigerant from the system. Record the amount of refrigerant and oil recovered for proper recharging. Verify system pressure reads 0 PSI on manifold gauges before proceeding.
2. 2

   Locate orifice tube assembly
   Identify the liquid line running from the condenser to the evaporator. The orifice tube is typically installed in a housing along this line, identifiable by a larger diameter section or inlet/outlet fittings. On the EDV 500, this is typically located near the passenger side firewall area. Verify correct location before disconnection.
3. 3

   Disconnect liquid line at orifice tube housing
   Using appropriate line wrenches, carefully disconnect the AC line fittings at both sides of the orifice tube housing. Support the lines to prevent stress on connections. Cap or plug the open lines immediately to prevent moisture and contaminant entry. Remove and discard the old O-rings from the fittings.
4. 4

   Remove orifice tube housing
   Remove any mounting brackets or clips securing the orifice tube housing to the vehicle. Carefully extract the housing from the line. Note the orientation and positioning for reinstallation. Inspect the housing for debris or damage.
5. 5

   Extract old orifice tube
   Remove the old orifice tube from the housing. The tube may be retained by tabs or pressure fit. Carefully extract it using appropriate tools, avoiding damage to the housing bore. Inspect the old tube screens for debris or metal particles which may indicate compressor failure. If excessive contamination is present, inspect compressor and consider system flush.
6. 6

   Clean housing and inspect system
   Thoroughly clean the orifice tube housing bore using lint-free shop towels. Inspect for scratches, corrosion, or damage. Check the recovered oil for metal particles or contamination. If contamination is severe, the AC system may require additional service including compressor inspection or replacement.
7. 7

   Install new orifice tube
   Install the new orifice tube into the housing, ensuring correct orientation. The inlet side (with larger screen) must face toward the condenser. The tube should seat fully with screen mesh visible on both ends. Verify the tube is securely retained in the housing.
8. 8

   Install new O-rings
   Lubricate new O-rings with appropriate PAG oil for R-1234yf systems. Install new O-rings on both sides of the AC line fittings. Ensure O-rings are properly seated in their grooves without twisting or damage.
9. 9

   Reinstall orifice tube housing
   Position the orifice tube housing back into the AC line with correct orientation (inlet toward condenser). Secure any mounting brackets or clips. Ensure the housing is properly supported and aligned before connecting lines.
10. 10

    Reconnect AC lines
    Remove caps from AC lines and reconnect fittings to both sides of the orifice tube housing. Hand-tighten fittings first to ensure proper thread engagement. Tighten fittings to manufacturer specification using line wrenches. Since specific torque values are not provided in the database, tighten to snug plus 1/6 turn (approximately 60 degrees) past hand-tight, typical for AC line fittings.
11. 11

    Vacuum system
    Connect vacuum pump to AC service ports and evacuate the system for minimum 45 minutes to remove all air and moisture. Monitor vacuum gauge for proper vacuum level (29+ inches Hg). After evacuation, close valves and monitor for 10 minutes to verify system holds vacuum, indicating no leaks.
12. 12

    Charge AC system
    Using the refrigerant recovery/charging machine and digital scale, charge the system with the amount of R-1234yf refrigerant recovered (or manufacturer specification if significantly different). Add appropriate amount of PAG oil to compensate for oil lost in removed components (typically 1-2 oz). Follow machine procedures for accurate charging.
13. 13

    Leak test system
    With system charged, use electronic leak detector or UV dye method to check all connections for leaks, paying special attention to the orifice tube housing connections. Verify no refrigerant leaks are detected. If leaks are found, recover refrigerant, repair, and repeat evacuation and charging procedures.
14. 14

    Reinstall underbody panels
    Reinstall any underbody panels, splash shields, or trim components that were removed for access. Ensure all fasteners are properly secured.
15. 15

    Reconnect battery and test system
    Reconnect the 12V battery negative terminal. Start the vehicle and activate the AC system. Allow system to run for 10 minutes and verify proper cooling performance. Check that compressor engages, blower operates at all speeds, and vent temperature reaches appropriate levels (typically 38-42°F at center vents on maximum cooling).

Reassembly

1. Ensure all AC line connections are properly tightened and show no signs of refrigerant leaks
2. Verify all underbody panels and shields are reinstalled with proper fasteners
3. Confirm 12V battery is securely reconnected with clean, tight connections
4. Document the amount of refrigerant and oil added to the system for future service reference

Verification

• Run AC system for 15 minutes and verify consistent cold air output from all vents
• Check center vent temperature with thermometer (should be 38-42°F at maximum cooling)
• Verify AC compressor cycles properly and no unusual noises are present
• Confirm no refrigerant odor or visible oil leaks around orifice tube housing connections
• Use leak detector to perform final check of all serviced connections
• Verify AC system performance matches pre-service operation or better
• Test AC operation in various modes (defrost, floor, vent) to ensure proper function

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