AC Compressor Oil Add

This procedure covers adding PAG oil to the AC system of a 2016-2021 Honda Civic 1.5L Turbo to maintain proper compressor lubrication after component replacement or refrigerant loss.

Warnings

Tools required

Parts

• AC O-ring kit × 1 — Use OEM Honda AC O-ring kit
• R-1234yf refrigerant × 1 — As needed for recharge

Fluids

• Honda ND-11 PAG Oil (or equivalent compatible with R-1234yf) — 0.125 qt

Preparation

1. Verify the engine is cold before beginning work
2. Park vehicle on level surface and engage parking brake
3. Ensure AC recovery equipment is certified for R-1234yf refrigerant
4. Confirm the correct PAG oil type (Honda ND-11 or compatible ND-11 for R-1234yf systems)
5. Determine oil quantity needed: 2 oz if compressor replaced, 1 oz if condenser replaced, 0.5 oz if evaporator replaced, or measured amount if recovered during service
6. Connect AC recovery machine and recover all refrigerant from the system per EPA regulations

Procedure

1. 1

   Access the AC service ports
   Locate the low-side service port on the suction line near the firewall and high-side port on the discharge line near the compressor. Remove dust caps from both ports. Clean the area around the ports with a clean shop towel.
2. 2

   Verify system is fully evacuated
   Confirm the AC recovery machine shows zero pressure in the system. If any pressure remains, complete the recovery process before proceeding. System must be completely empty before opening any fittings.
3. 3

   Remove the low-side AC line fitting
   Using appropriate wrenches, slowly loosen the AC line fitting at the low-side service port or at the compressor suction port (choose the most accessible location). Allow any residual pressure to bleed off. Once pressure is released, fully remove the fitting and immediately cap the open line to prevent moisture entry.
   ⚠Even after recovery, small amounts of refrigerant may remain. Loosen fittings slowly and allow pressure to equalize before full removal.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
4. 4

   Inspect and replace O-rings
   Remove the old O-rings from the AC line fitting. Inspect the fitting surfaces for damage, corrosion, or debris. Clean with a lint-free cloth. Install new O-rings from the kit, ensuring they are properly seated in the groove.
5. 5

   Add PAG oil to the system
   Using the PAG oil injector tool, measure the required amount of ND-11 PAG oil. Connect the injector to the open AC line or port. Slowly inject the measured oil quantity into the system. For compressor replacement, distribute oil by rotating the compressor clutch hub 10 revolutions by hand before installation.
   ⚠Do not overfill. Excess oil will reduce cooling efficiency and can damage the compressor.
6. 6

   Apply PAG oil to new O-rings
   Apply a thin coating of fresh ND-11 PAG oil to the new O-rings on both the male and female sides of the AC line fitting. This ensures proper sealing and prevents O-ring damage during installation.
7. 7

   Reconnect the AC line fitting
   Hand-thread the AC line fitting back into place, ensuring proper alignment to avoid cross-threading. Once hand-tight, use a torque wrench to tighten the fitting to specification. Do not over-torque as this can damage the O-ring seal.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
8. 8

   Evacuate the AC system
   Connect the AC vacuum pump to the service ports using the manifold gauge set. Evacuate the system for a minimum of 45 minutes to remove all air and moisture. Monitor the vacuum gauge to ensure it reaches and holds at least 29 inches of mercury (98 kPa).
   ℹ️Proper evacuation is critical. Moisture in the system will cause acid formation and compressor failure.
9. 9

   Perform vacuum hold test
   Close the manifold valves and turn off the vacuum pump. Observe the vacuum gauge for 15 minutes. The vacuum should hold steady. If vacuum drops, there is a leak that must be found and repaired before recharging.
10. 10

    Recharge the AC system
    Using the AC service machine or manifold gauges, recharge the system with R-1234yf refrigerant to the specified capacity (approximately 14.1 oz total). Add refrigerant through the low-side port only with the engine running at 1500 RPM and AC on MAX cool. Monitor pressures during the process.
    ⚠Never exceed the specified refrigerant capacity. Overcharging can cause high pressures and compressor damage.

Reassembly

1. Verify all AC line fittings are torqued to specification and have no visible leaks
2. Reinstall dust caps on service ports
3. Ensure no tools or shop towels are left in the engine compartment

Verification

• Start the engine and turn AC to MAX cool with blower on high
• Allow system to run for 5 minutes and verify cold air output from vents (should reach 38-45°F at vents)
• Check AC compressor engages and disengages normally with AC button
• Monitor gauge pressures: Low side should be 25-35 PSI, high side 200-250 PSI at idle with 80°F ambient temperature
• Inspect all AC line fittings for signs of refrigerant oil leakage (indicates seal failure)
• Use electronic leak detector around all disturbed fittings to verify no refrigerant leaks
• Verify AC compressor operates quietly without unusual noises or vibration

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