AC Orifice Tube

This procedure covers the replacement of the AC orifice tube in a 2025 Rivian EDV 500 electric delivery van, requiring refrigerant recovery, partial AC system disassembly, and system recharge.

Warnings

Tools required

Parts

• AC orifice tube assembly × 1 — Use OEM Rivian specification
• AC line O-ring kit × 1 — Use OEM specification for R-1234yf
• R-1234yf refrigerant × 1 — Per system capacity specification
• PAG oil for R-1234yf systems × 1 — Use OEM specification
• AC system seal conditioner × 1 — R-1234yf compatible

Preparation

1. Park vehicle on level surface and engage parking brake
2. Verify battery state of charge is above 20% to maintain vehicle systems during service
3. Place vehicle in service mode per manufacturer diagnostic tool (disables HVAC auto-start)
4. Raise vehicle on lift or securely support on jack stands to access underbody AC lines
5. Remove front passenger side underbody panel fasteners to access AC line routing
6. Connect refrigerant identifier to service port and verify system contains only R-1234yf
7. Document pre-service AC system pressures with manifold gauges
8. Connect AC recovery machine to high and low side service ports

Procedure

1. 1

   Recover refrigerant from AC system
   Start the recovery machine and evacuate all refrigerant from the system according to machine instructions. Monitor recovery tank weight to document amount removed. Continue recovery until system pressure reaches zero and stabilizes for at least 5 minutes. Record the amount of refrigerant and oil recovered for proper recharge quantities. System capacity is approximately 1.5-2.0 lbs of R-1234yf.
2. 2

   Locate and access orifice tube
   Identify the liquid line connection point near the evaporator inlet, located on the front passenger side of the vehicle behind the underbody panel. The orifice tube is inside the liquid line inlet at the evaporator or in an inline housing. Trace the line from the condenser outlet to locate the orifice tube housing, which may have a slight bulge or visible crimp indicating tube location. Clean the connection area thoroughly to prevent contamination.
3. 3

   Disconnect liquid line at orifice tube location
   Using appropriate flare nut wrench or AC line disconnect tool, carefully disconnect the liquid line at the fitting nearest the orifice tube. Support both sides of the connection to prevent line damage. Be prepared for residual refrigerant or oil to drain - have shop towels ready. Cap open connections immediately to prevent moisture and contamination entry. If using spring-lock couplings, ensure disconnect tool fully releases the internal garter spring before separating.
4. 4

   Remove old orifice tube
   Inspect the line inlet for the orifice tube - it should be visible just inside the female fitting. Use orifice tube removal tool or needle-nose pliers to carefully grasp the tube and extract it. If tube is stuck, use a pick tool to gently work around the edges. Be very careful not to damage the aluminum line seat. Inspect removed tube for debris, metal particles, or discoloration indicating compressor failure or contamination. If significant debris is present, inspect and possibly flush entire system.
5. 5

   Inspect AC system condition
   Examine the removed orifice tube screen for metal particles, black residue, or excessive debris. Check recovered oil color - it should be clear to light yellow. Dark or metallic oil indicates compressor wear. Inspect line fittings and O-ring sealing surfaces for damage, corrosion, or scoring. If contamination is found, system flushing and additional component inspection may be required before proceeding.
6. 6

   Prepare new orifice tube for installation
   Remove new orifice tube from packaging and verify correct part number for EDV 500 application. Check that inlet and outlet screens are intact and properly positioned. Lightly lubricate the O-rings on the orifice tube body with fresh PAG oil compatible with R-1234yf systems. Do not use petroleum-based lubricants. Ensure the tube orientation is correct - arrow or marking on tube body should point in direction of refrigerant flow (toward evaporator).
7. 7

   Install new orifice tube
   Carefully insert the new orifice tube into the liquid line inlet, ensuring proper orientation with flow direction arrow pointing toward evaporator. Push tube fully into the line until it seats against the internal stop - you should feel positive engagement. The tube should sit approximately 1/4 to 1/2 inch inside the line. Verify tube is fully seated and cannot be easily pulled out. Do not force or drive the tube beyond its natural seating point.
8. 8

   Replace O-rings and reconnect lines
   Remove old O-rings from line fittings and discard. Install new O-rings from kit, ensuring correct size for each connection. Lubricate new O-rings with PAG oil. Carefully align and reconnect the liquid line fittings, ensuring threads engage properly without cross-threading. Hand-tighten connections first, then use flare nut wrench to tighten. For spring-lock couplings, push together until you hear/feel the garter spring click into place, then verify connection by pulling on both sides.
9. 9

   Add replacement refrigerant oil
   Calculate oil replacement amount based on recovered quantity (typically 1-2 oz for orifice tube replacement). Using refrigerant oil injector, add the appropriate amount of new PAG oil approved for R-1234yf systems through the low-side service port. Use only oil specified by Rivian for electric drive unit compatibility. Do not overfill as this reduces AC efficiency and can damage compressor.
10. 10

    Evacuate AC system
    Connect vacuum pump to both service ports through manifold gauge set. Start vacuum pump and evacuate system to below 500 microns. Continue evacuation for minimum 30-45 minutes. Close manifold valves and stop pump. Monitor vacuum gauge - system should hold vacuum with no more than 100 micron rise over 10 minutes. If vacuum does not hold, there is a leak that must be located and repaired before charging. Acceptable vacuum hold indicates system is sealed and moisture-free.
11. 11

    Recharge AC system with R-1234yf
    With system under vacuum, connect R-1234yf refrigerant supply to manifold gauge set. Open low-side valve and allow system to draw in refrigerant. Charge system to the weight specified on the underhood label (typically 1.5-2.0 lbs total). Use charging scale to monitor exact weight. For faster charging, vehicle can be in service mode with AC requested on, but never exceed 40 psi on low side during charging. Add refrigerant through low side only. Top off on high side only if vehicle is off.
12. 12

    Add UV dye if specified
    If UV leak detection dye is not already in system, inject manufacturer-specified amount (typically 0.25-1.0 oz) through low-side service port using dye injector. Ensure dye is compatible with R-1234yf and PAG oil. This aids in future leak detection. Record dye addition on service documentation.
13. 13

    Verify system operation and pressures
    Exit service mode and start vehicle AC system at maximum cooling with recirculation on. Allow system to run for 5-10 minutes. Monitor manifold gauges: low side should stabilize at 25-45 psi, high side at 180-250 psi (varies with ambient temperature). Check evaporator outlet temperature at center vent - should achieve 40-50°F with 75-85°F ambient. Listen for unusual compressor noises. Verify cooling fan operation when pressures rise.
14. 14

    Perform leak check
    Using electronic leak detector approved for R-1234yf, carefully check all disturbed connections, focusing on orifice tube location and line fittings. Check service port caps and valve cores. If UV dye was added, use UV light and glasses to inspect for fluorescent traces. Pay special attention to areas that were disconnected. Any leaks must be repaired and system re-evacuated and recharged.
15. 15

    Reinstall underbody panels and finalize
    Clean any spilled refrigerant oil from components and underbody. Reinstall front passenger underbody access panel and secure all fasteners. Lower vehicle from lift. Test AC system operation at various temperature settings and fan speeds. Document final system pressures, refrigerant amount added, oil added, and any observations on repair order. Verify no warning lights or HVAC fault codes in vehicle system.

Reassembly

1. Ensure all AC line connections are properly torqued and secured with no visible gaps
2. Verify underbody panels are reinstalled with all fasteners in place
3. Confirm service mode is exited and vehicle systems return to normal operation
4. Document total refrigerant and oil quantities added for future service reference

Verification

• AC system maintains proper operating pressures: 25-45 psi low side, 180-250 psi high side at idle with AC on max
• Center dash vent temperature reaches 40-50°F within 5 minutes of operation at 75-85°F ambient
• No refrigerant leaks detected at orifice tube location or any disturbed connections
• No unusual noises from AC compressor or system operation
• AC compressor cycles normally without short cycling or continuous operation
• No HVAC system fault codes stored in vehicle diagnostics
• System pressures remain stable during extended operation with no loss of cooling performance

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