Replace the AC orifice tube in the evaporator inlet line to restore proper refrigerant flow and AC system performance.

Warnings

Tools required

Parts

• AC orifice tube × 1 — Use OEM specification
• AC line O-rings × 4 — Use OEM specification
• R-134a refrigerant × 1 — Typically 2.25-2.5 lbs for system
• PAG 46 refrigerant oil × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure engine is cool to the touch before beginning work
3. Verify AC system has been properly diagnosed and orifice tube replacement is confirmed as necessary
4. Connect AC recovery machine and fully recover all refrigerant from the system following EPA guidelines
5. Document recovered refrigerant quantity for refill reference
6. Allow 10-15 minutes after recovery for system pressure to stabilize at atmospheric pressure

Procedure

1. 1

   Access the evaporator inlet line
   Locate the evaporator inlet line on the passenger side of the firewall. This is the line running from the condenser to the evaporator, typically the smaller diameter liquid line. Remove any engine covers or components obstructing access to the line connection near the firewall.
2. 2

   Disconnect the evaporator inlet line
   Using appropriate line wrenches, carefully loosen and disconnect the evaporator inlet line at the coupling near the firewall where the orifice tube is located. The orifice tube is typically positioned in the inlet line just before it enters the evaporator. Cap open lines immediately to prevent moisture ingress.
   ⚠Even after recovery, residual refrigerant may remain. Wear protective equipment and work in a well-ventilated area.
3. 3

   Remove the old orifice tube
   Insert the orifice tube remover tool into the evaporator inlet line opening. The orifice tube is a fixed restriction device with a mesh screen. Carefully thread the remover tool onto or around the orifice tube, then pull straight out. If the tube is stuck or corroded, gently rotate while pulling. Inspect the removed tube for debris, metal particles, or damage to the screen.
   ⚠Do not force the removal tool. Excessive force can push the orifice tube deeper into the line or damage the tube itself, requiring line replacement.
4. 4

   Inspect and clean the line
   Examine the interior of the evaporator inlet line for debris, metal shavings, or contaminants. If metal particles are present, this indicates compressor failure and the entire system must be flushed before proceeding. Clean the line connection surfaces and o-ring sealing areas thoroughly with a lint-free cloth. Inspect the line for cracks or damage.
5. 5

   Install the new orifice tube
   Verify the new orifice tube matches the original part number and has the correct color code for your system. Lightly coat the new orifice tube O-rings with fresh PAG 46 oil. Insert the new orifice tube into the evaporator inlet line with the correct orientation (mesh screen should face toward the condenser/liquid line). Push firmly until the tube seats completely and is flush with the line opening.
   ℹ️Orifice tubes are directional. Arrow on tube body must point in direction of refrigerant flow (toward evaporator).
6. 6

   Replace O-rings and reconnect line
   Remove old O-rings from both sides of the line connection and discard. Install new O-rings of correct size, coating them with fresh PAG 46 oil. Reconnect the evaporator inlet line to the coupling, ensuring proper alignment. Hand-tighten first, then use line wrenches to torque to specification.
   ⚠Never reuse old O-rings. Always use new O-rings specifically designed for AC systems to prevent leaks.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
7. 7

   Add refrigerant oil
   Add the appropriate amount of PAG 46 refrigerant oil to compensate for oil lost during recovery and trapped in the old orifice tube. Typically add 1-2 ounces through the compressor service port or as specified by service information based on total oil capacity and amount recovered.
8. 8

   Evacuate the AC system
   Connect the vacuum pump to the AC service ports using the manifold gauge set. Evacuate the system to at least 29 inches of mercury (Hg) vacuum. Maintain vacuum for minimum 30-45 minutes to remove all air and moisture. Monitor vacuum gauge for any rise in pressure which would indicate a leak.
   ⚠Inadequate vacuum time will leave moisture in the system, potentially causing compressor damage and reduced cooling performance.
9. 9

   Perform leak test
   After evacuation, close manifold valves and shut off vacuum pump. Monitor system vacuum for 10 minutes. Vacuum should hold steady with no pressure rise. If vacuum drops, there is a leak that must be repaired before charging the system.
10. 10

    Recharge the AC system
    Using the refrigerant scale and following proper charging procedures, recharge the system with the correct amount of R-134a refrigerant (typically 2.25-2.5 lbs total for this system, verify on underhood label). Charge through the low-side service port with engine running and AC on maximum cold. Monitor pressures on manifold gauges throughout charging process.
    ⚠Do not overcharge the system. Overcharging can cause high system pressures, reduced cooling, and compressor damage.

Reassembly

1. Reinstall any engine covers or components removed for access
2. Double-check all AC line connections are properly torqued and secure
3. Verify no tools or parts are left in engine compartment

Verification

• Start engine and turn AC to maximum cold with blower on high
• Verify compressor engages and cycles normally
• Check manifold gauge pressures: low side should be 25-45 PSI, high side should be 200-300 PSI at ambient temperature (values vary with temperature)
• Verify cold air is blowing from vents with vent temperature 35-45°F below ambient
• Inspect all AC line connections for leaks using UV dye detection or electronic leak detector
• Allow system to run for 10-15 minutes and recheck pressures for stability
• Test AC performance under various engine speeds and confirm proper cooling

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