This procedure covers the removal and replacement of the low-side AC hose on a 2016-2024 Hyundai Tucson with the 2.5L I4 engine, including refrigerant recovery, hose replacement, and system recharge.

Warnings

Tools required

Parts

• Low-side AC hose assembly × 1 — Use OEM specification
• AC line O-rings × 4 — Use OEM specification
• R-134a refrigerant × 1 — Check AC label under hood for capacity
• PAG 46 compressor oil × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure engine and AC system have been off for at least 10 minutes
3. Raise vehicle on lift or securely support on jack stands at manufacturer lift points
4. Remove front belly pan or underbody shield (10mm fasteners) to access AC lines from below
5. Locate the low-side AC hose running from the accumulator/drier to the compressor
6. Connect AC recovery machine to high and low side service ports

Procedure

1. 1

   Recover refrigerant from AC system
   Connect the AC recovery machine to both service ports. Follow the recovery machine manufacturer's instructions to completely evacuate all refrigerant from the system. Record the amount of refrigerant and oil recovered for proper refilling. Wait until recovery machine indicates system is at vacuum and no refrigerant remains.
2. 2

   Disconnect battery negative terminal
   Disconnect the negative battery cable using a 10mm socket and secure it away from the terminal. Wait 3 minutes for airbag system to discharge before proceeding.
3. 3

   Remove engine cover
   Remove the plastic engine cover by pulling upward on the front edge to release the clips, then lift away from the engine bay. This provides better access to the upper AC line connections.
4. 4

   Disconnect low-side hose at accumulator/drier
   Working from the engine bay, locate the connection point where the low-side hose connects to the accumulator/drier near the firewall passenger side. Use a 17mm flare nut wrench to carefully loosen the fitting. Support the line to prevent twisting the accumulator. Once loose, separate the connection and immediately cap both openings to prevent contamination. Remove and discard the old O-rings from the fitting.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
5. 5

   Disconnect low-side hose at compressor
   From underneath the vehicle, locate where the low-side hose connects to the compressor on the passenger side of the engine. Use a 17mm flare nut wrench to loosen the fitting at the compressor. Support the hose and compressor line to prevent damage. Separate the connection and cap the compressor port immediately. Remove and discard old O-rings.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
6. 6

   Remove hose mounting brackets
   Locate the AC hose mounting bracket(s) along the hose routing path. Remove the mounting bolts using a 10mm or 12mm socket as applicable. Note the routing path and any clips securing the hose for reinstallation reference. Take a photo if needed.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
7. 7

   Remove old low-side AC hose
   Carefully maneuver the old low-side hose assembly out of the engine bay, working it past other components. Pay attention to the routing path through any brackets or clips. Inspect the removed hose for signs of damage, leaks, or contamination to identify the failure cause.
8. 8

   Prepare new AC hose and fittings
   Unpack the new low-side AC hose assembly. Install new O-rings on all four connection points (two on each end of the hose). Lightly coat each new O-ring with fresh PAG 46 compressor oil to ensure proper sealing and prevent damage during installation. Do not reuse old O-rings.
9. 9

   Install new low-side hose
   Route the new AC hose assembly through the engine bay following the same path as the original. Ensure the hose does not contact sharp edges, hot exhaust components, or moving parts. Position the hose so both end fittings align with their respective connection points without stress or excessive bending.
10. 10

    Connect hose to compressor
    From underneath the vehicle, align the hose fitting with the compressor port. Remove the protective cap and hand-thread the fitting to ensure proper alignment. Once hand-tight, use a 17mm flare nut wrench and torque wrench to tighten to specification. Hold the compressor port steady with a backup wrench if needed to prevent component damage.
    Torque spec

    AC Line Fittings20 Nm (15 lb-ft)
11. 11

    Connect hose to accumulator/drier
    From the engine bay, align the hose fitting with the accumulator/drier port. Remove the protective cap and hand-thread the fitting carefully. Once hand-tight, use a 17mm flare nut wrench and torque wrench to tighten to specification. Support the accumulator to prevent stress on mounting points.
    Torque spec

    AC Line Fittings20 Nm (15 lb-ft)
12. 12

    Reinstall hose mounting brackets
    Secure the AC hose to all mounting brackets along its routing path. Install and torque the mounting bolts to specification. Ensure the hose is properly positioned in all clips and has adequate clearance from moving or hot components.
    Torque spec

    Mounting Bolts27 Nm (20 lb-ft)
13. 13

    Vacuum test AC system
    Connect the vacuum pump to the AC system service ports. Evacuate the system to at least 29 inches of mercury (98 kPa) vacuum. Hold vacuum for a minimum of 30 minutes. Monitor the gauge - if vacuum holds steady, the system has no leaks. If vacuum drops, locate and repair the leak before proceeding.
14. 14

    Recharge AC system
    Using the AC recovery/recharge machine, add the correct amount of R-134a refrigerant as specified on the underhood AC label (typically 450-550 grams for this model). Add PAG 46 oil equal to the amount removed during recovery plus 20ml to account for hose replacement. Follow the recharge machine instructions for proper refrigerant and oil addition.
15. 15

    Reinstall components and reconnect battery
    Reinstall the front underbody shield/belly pan with 10mm fasteners. Reinstall the engine cover by aligning clips and pressing down firmly. Reconnect the negative battery cable and torque to 10 Nm (7 lb-ft).

Reassembly

1. Ensure all AC line fittings are torqued to specification and O-rings are properly lubricated
2. Verify AC hose routing has adequate clearance from hot and moving components
3. Confirm all mounting brackets are secured and hose is properly supported
4. Double-check that vacuum test was successful before recharging system

Verification

• Start the engine and turn AC to maximum cooling with fan on high
• Allow system to run for 5 minutes and verify cold air output from vents
• Check that compressor clutch engages and cycles normally
• Inspect all AC line connections for signs of oil residue or refrigerant leaks
• Use AC leak detector or soap solution on all fittings to verify no leaks present
• Verify AC system pressures are within specification using manifold gauges (low side 25-35 PSI at idle, high side 200-250 PSI)
• Check for unusual noises from compressor or hissing sounds indicating leaks
• Verify vent temperature is 40-50°F (4-10°C) colder than ambient temperature

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