Complete removal and replacement of the AC compressor on a 2016-2021 Honda Civic 1.5L Turbo, including refrigerant recovery, component installation, and system recharge.

Warnings

Tools required

Parts

• AC Compressor assembly × 1 — Use OEM specification
• AC line O-rings (high and low side) × 1 — Use OEM specification
• Serpentine belt × 1 — Replace if worn or contaminated
• PAG 46 compressor oil × 1 — Use OEM specification
• R-134a refrigerant × 1 — Approximately 16-18 oz total system capacity

Fluids

• PAG 46 compressor oil — 0.25 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow engine to cool completely (minimum 2 hours)
3. Disconnect negative battery terminal and wait 3 minutes for airbag system discharge
4. Raise front of vehicle and support on jack stands at manufacturer jacking points
5. Remove passenger-side front wheel for improved access
6. Remove plastic engine splash shield and wheel well liner sections for compressor access
7. Connect AC recovery machine and fully recover refrigerant from system per EPA regulations
8. Measure and record amount of oil recovered for replacement calculation

Procedure

1. 1

   Remove serpentine belt
   Locate the belt tensioner on the right side of the engine. Using a 14mm socket, rotate the tensioner clockwise to release tension. Slide the serpentine belt off the pulleys, noting the routing path. Allow tensioner to return slowly. Remove belt from engine bay. Inspect belt for oil contamination from failed compressor seal; replace if contaminated.
2. 2

   Disconnect compressor electrical connector
   Locate the compressor clutch electrical connector on the front of the compressor. Press the locking tab and pull the connector straight off. If equipped with a connector bolt, remove using 10mm socket.
   Torque spec

   Clutch Connector Bolt8 Nm (6 lb-ft)
3. 3

   Disconnect AC refrigerant lines
   Locate the high-side and low-side AC lines at the rear of the compressor. Using appropriate line wrenches (typically 12mm and 14mm), loosen and remove both line fittings. Immediately cap all open fittings with plastic caps to prevent moisture ingress and contamination. Remove and discard old O-rings from the lines.
   ⚠If any refrigerant sprays out during disconnection, STOP immediately and verify system was fully recovered. Do not proceed until pressure is zero.
4. 4

   Remove compressor mounting bolts
   The compressor is secured by three mounting bolts accessible from below and from the wheel well. Remove the upper mounting bolt (12mm), then the two lower mounting bolts (12mm). Support the compressor weight while removing the final bolt to prevent it from falling.
   ⚠Compressor weighs approximately 15 lbs. Support it during removal to prevent damage to surrounding components.
5. 5

   Remove AC compressor from vehicle
   Carefully maneuver the compressor out through the wheel well opening, tilting as needed to clear the frame rail and subframe. Keep the compressor upright to prevent oil from draining into the clutch assembly. Drain any remaining oil from the old compressor into a graduated container and measure.
6. 6

   Prepare new compressor
   Remove shipping caps from new compressor. Drain the shipping oil from the new compressor and measure. Calculate the required oil charge: add the amount of oil recovered from the system to the amount drained from the old compressor, then subtract the shipping oil from the new compressor. Add the calculated amount of fresh PAG 46 oil to the new compressor through the suction port. Rotate the compressor clutch hub by hand 10 times to distribute oil internally.
   ℹ️Typical oil charge is 80-120ml total. If more than 30ml was recovered from the system, inspect for oil circulation issues.
7. 7

   Install new compressor
   Maneuver the new compressor into position through the wheel well opening. Align the mounting holes with the bracket. Hand-thread all three mounting bolts before tightening any. Tighten the compressor mounting bolts to specification in a crossing pattern.
8. 8

   Install new O-rings and connect AC lines
   Lubricate new O-rings lightly with PAG oil and install on both AC line fittings. Ensure O-rings are seated properly in the grooves without twisting. Remove caps from compressor ports. Connect both the high-side and low-side AC lines to the compressor, hand-tightening first. Using line wrenches, tighten the AC line fittings to specification.
   ⚠Do not over-tighten refrigerant line fittings. Excessive torque can damage the O-ring seal or crack aluminum fittings.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
9. 9

   Reconnect electrical connector
   Connect the compressor clutch electrical connector until it clicks into place. If equipped with a connector bolt, install and tighten to specification.
   Torque spec

   Clutch Connector Bolt8 Nm (6 lb-ft)
10. 10

    Install serpentine belt
    Route the serpentine belt around all pulleys except the tensioner pulley, following the original routing pattern (check under-hood decal if needed). Rotate the tensioner clockwise with a 14mm socket to create slack. Slide the belt onto the tensioner pulley and slowly release the tensioner. Verify the belt is properly seated in all pulley grooves.
11. 11

    Reinstall underbody components
    Reinstall the wheel well liner sections and engine splash shield. Reinstall the passenger-side front wheel and torque lug nuts to specification (108 Nm / 80 lb-ft). Lower the vehicle to the ground.
12. 12

    Evacuate and recharge AC system
    Connect AC service machine to high and low side service ports. Perform a vacuum test by pulling the system down to 29 inches of mercury for a minimum of 30 minutes. Monitor for vacuum decay; system should hold vacuum indicating no leaks. After successful vacuum test, recharge the system with the specified amount of R-134a refrigerant (approximately 16-18 oz, verify on under-hood label). Add UV dye if desired for future leak detection.
    ⚠If vacuum decays more than 2 inches in 30 minutes, there is a leak. Do not recharge until leak is found and repaired.

Reassembly

1. Reconnect negative battery terminal
2. Double-check all electrical connections and AC line fittings for security
3. Verify serpentine belt is properly routed and seated on all pulleys

Verification

• Start the engine and allow to reach operating temperature
• Turn AC to maximum cold with blower on high
• Verify compressor clutch engages (clicking sound and clutch hub rotation visible)
• Check for cold air from vents within 2-3 minutes; center vent temperature should reach 40-50°F
• Inspect all AC line connections for signs of refrigerant leaks (oil residue or frost)
• Use UV dye light to check for leaks if dye was added
• Verify high-side pressure reads 200-250 PSI and low-side reads 25-35 PSI at idle with AC on (ambient temperature 75-85°F)
• Listen for unusual noises from compressor during operation
• Test AC performance during a road test to ensure proper cooling under load

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