AC Hose Assembly

Replace the AC hose assembly on a 2016-2021 Honda Civic 1.5L Turbo, including recovery and recharge of refrigerant, removal of damaged hoses, and installation of new hoses with proper sealing.

Warnings

Tools required

Parts

• AC hose assembly (specific to location being replaced) × 1 — Use OEM specification
• AC line O-rings × 4 — Use OEM specification
• PAG oil for AC system × 1 — ND-11 or equivalent

Fluids

• R-1234yf refrigerant

Preparation

1. Verify which AC hose assembly needs replacement (suction line, liquid line, or discharge line)
2. Ensure AC recovery machine is certified for R-1234yf refrigerant
3. Park vehicle on level ground and engage parking brake
4. Allow engine to cool completely (minimum 2 hours after operation)
5. Disconnect negative battery terminal and wait 3 minutes for airbag system discharge
6. Place fender covers to protect paint during work
7. Document AC system pressure and refrigerant amount before recovery for proper recharge

Procedure

1. 1

   Recover AC Refrigerant
   Connect AC recovery machine to service ports (low-side and high-side). Verify refrigerant type with identifier. Run recovery cycle until system pressure reaches vacuum (below 0 PSI). Recovery must be performed by EPA Section 609 certified technician. Allow machine to recover for minimum 30 minutes or until complete.
2. 2

   Remove Engine Cover and Access Components
   Remove plastic engine cover by pulling upward on four grommet points. Set aside. For better access to AC lines, remove air intake duct by loosening clamp at throttle body and releasing clips at air box. This provides clear access to compressor and hose routing.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
3. 3

   Locate and Identify AC Hose to Replace
   Identify the specific hose assembly requiring replacement. Suction line (large diameter, low-side) runs from evaporator to compressor. Discharge line (high-side) runs from compressor to condenser. Liquid line runs from condenser to expansion valve. Note routing path and any clips or brackets before removal.
4. 4

   Remove AC Line Mounting Hardware
   Remove any mounting brackets or clips securing the AC hose assembly to chassis or engine. Typically uses 10mm bolts at mounting points. Note exact location and orientation of brackets for reinstallation. Some lines have rubber isolator mounts to reduce vibration.
   Torque spec

   Mounting Bolts26 Nm (19 lb-ft)
5. 5

   Disconnect AC Line at Compressor or First Junction
   Using flare nut wrench or appropriate socket, loosen AC line fitting at compressor or first connection point. For spring-lock couplings, use disconnect tool. Once fitting is loose, carefully remove line. Cap or plug open ports immediately to prevent moisture and debris entry. Remove and discard old O-rings.
6. 6

   Disconnect AC Line at Second Connection Point
   Trace hose to second connection point (evaporator, condenser, or expansion valve depending on which line). Remove fitting using same technique. If accessing firewall connections, may need to remove plastic cowl covers under hood near windshield. Cap all open ports immediately.
7. 7

   Remove Old AC Hose Assembly
   Carefully extract old AC hose assembly following its routing path. Note any grommets through firewall or mounting points. Check removed hose for signs of damage: abrasion, cracks, oil residue, or punctures to identify failure cause. If hose shows signs of debris, AC system may require flushing.
8. 8

   Prepare New AC Hose Assembly
   Remove new AC hose from sealed packaging just before installation. Inspect new O-rings (should be green for R-1234yf systems). Lightly coat new O-rings with fresh PAG oil (ND-11). Apply thin film of PAG oil to tube ends. Add specified amount of PAG oil into open hose end to replace oil lost with old hose (typically 20-30ml depending on hose).
9. 9

   Route and Install New AC Hose
   Route new AC hose assembly following exact path of original. Ensure hose does not contact any sharp edges, exhaust components, or moving parts. Check that hose has adequate clearance from engine mounts during full suspension travel. Install any firewall grommets ensuring proper seal.
10. 10

    Connect AC Line Fittings
    Install new O-rings into fittings if not pre-installed. Connect AC line to both connection points, ensuring proper alignment. Thread fittings by hand first to prevent cross-threading. Once hand-tight, use torque wrench to tighten AC line fittings to specification. Do not over-tighten as this can damage O-rings or fittings.
    Torque spec

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

    Reinstall Mounting Brackets
    Install all mounting brackets and clips in original positions. Torque mounting bolts to specification. Ensure hose is properly supported and secured but not over-compressed by brackets. Hose should have slight flexibility but not excessive movement.
    Torque spec

    Mounting Bolts26 Nm (19 lb-ft)
12. 12

    Evacuate AC System
    Connect AC recovery/recharge machine vacuum pump to service ports. Run vacuum pump for minimum 45 minutes to remove all air and moisture from system. System should hold vacuum at 29.9 inHg or deeper. If vacuum drops more than 1 inHg in 10 minutes after pump shutdown, there is a leak - recheck all connections.
13. 13

    Recharge AC System
    With system under vacuum, begin refrigerant charge with R-1234yf only. Charge system to factory specification (typically 400-450 grams for 1.5T engine, verify on underhood label). Add UV dye if desired for future leak detection. Monitor low and high side pressures during charging. Do not overcharge system.
14. 14

    Reinstall Remaining Components
    Reinstall air intake duct and secure with clamp at throttle body. Reconnect any clips at air box. Install engine cover by pressing firmly onto four grommet mounts. Reconnect negative battery terminal. Clear any DTCs related to battery disconnect using scan tool if necessary.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)

Reassembly

1. Ensure all AC line fittings are torqued to specification and not leaking
2. Verify all mounting brackets are reinstalled and properly supporting hoses
3. Confirm AC hoses have proper clearance from exhaust and moving components
4. Double-check that R-1234yf refrigerant was used, not R-134a

Verification

• Start engine and turn AC to maximum cold, high fan speed
• Allow AC to run for 5 minutes, verify cold air from vents (38-42°F at center vent)
• Check low-side pressure: should be 25-35 PSI at idle with ambient temp 75-85°F
• Check high-side pressure: should be 150-250 PSI depending on ambient temperature
• Inspect all AC line connections with leak detector or soap solution - no bubbles should appear
• Use UV light to check for leaks if UV dye was added to system
• Listen for unusual noises from compressor during operation
• Verify AC compressor clutch engages and disengages properly
• Test AC performance during test drive under various load conditions
• Recheck all connection points after 24-48 hours of operation for any delayed leaks

More procedures for this vehicle