Auxiliary belt replacement: Detaching air conditioner compressor from holder/attaching - vehicles with 8-cyl. TDI engine — AUDI

🧭 Before you start

Fits: Audi A8 D4 (4H, 2010–2017)

• Also covered elsewhere: Electronic parts catalogue

Don't miss

• If electrical connectors to N280 and, for example, electric engine mounting are interchanged, no entry is made in event memory, but evaporator could ice up as air conditioner compressor is constantly activated.
• The bolts (arrows) have different lengths (the rear bolt may be longer). For this reason, mark the bolts when removing them to prevent interchange.
• Fit a washer (B) on each of the bolts (A) (different types of bolts; this illustration shows a hexagon bolt).
• If aluminium bolts have been used to secure the air conditioner compressor, (different versions Electronic parts catalogue), renew the aluminium bolts (do not re-use). Tightening torque for aluminium bolts 8 Nm +180°.

🔩 Torque settings

Values can differ between engine variants — check the code stamped on your block.

ℹ️ Always cross-check the exact figure against your vehicle's factory manual before final tightening — a wrong torque can damage the engine. These values are extracted from workshop data and may not cover every variant or revision.

📋 Procedure

1. ⚠ Different refrigerant and refrigerant oil capacity for vehicles with an 8-cyl. TDI engineOn account of the installation position of the air conditioner compressor (at the top of the engine), the quantity of refrigerant oil differs on vehicles with an 8-cyl. TDI engine from the quantity indicated on the rating plate of the air conditioner compressor Air conditioner with refrigerant R134a87Capacities for refrigerant R134a, refrigeration oil and approved refrigeration oils. — Remove top engine cover panel 10Engine cover panel; Removing and installing engine cover panel.
2. Detach retainers for electrical connectors.
3. Slacken off and detach poly V-belt 13Cylinder block, pulley end; Removing and installing poly V-belt
4. Mark electrical connector (2) for air conditioner compressor regulating valve N280 to avoid possible interchange with other connectors. [Note: If electrical connectors to N280 and, for example, electric engine mounting are interchanged, no entry is made in event memory, but evaporator could ice up as air conditioner compressor is constantly activated.]
5. Unplug N280 at electrical connector.

6. Unscrew bolts (arrows) (tightening torque 25 Nm). [Note: The bolts (arrows) have different lengths (the rear bolt may be longer). For this reason, mark the bolts when removing them to prevent interchange.] — 25 Nm (18 lb-ft)
7. Attach air conditioner compressor (A) to vehicle (e.g. with transportation shackle T40016(C) and a cable tie to front end module (B)) so that refrigerant hoses (D) are not kinked or strained. [Note: Fit a washer (B) on each of the bolts (A) (different types of bolts; this illustration shows a hexagon bolt).]
8. ⚠ Risk of damage to refrigerant lines and hoses.Do not stretch, kink or bend refrigerant lines and hoses. — Before securing the air conditioner compressor, check the position of both dowel sleeves (A) in the bracket or the compressor (B). [Note: There are different versions of the dowel sleeves (A) (different length); for correct version refer to Electronic parts catalogue.Make sure that dowel sleeves (A) are correctly positioned and that contact surfaces are clean. If the dowel sleeves are not installed correctly or the contact surfaces (C) at the bracket or air conditioner compressor are dirty or damaged, this could lead to misalignment between the air conditioner compressor and the engine. After a period of operation, misalignment can cause damage to the poly V-belt or the air conditioner compressor.]
9. Tighten bolts (arrows). [Note: If aluminium bolts have been used to secure the air conditioner compressor, (different versions Electronic parts catalogue), renew the aluminium bolts (do not re-use). Tightening torque for aluminium bolts 8 Nm +180°.]
10. Plug in electrical connector (2) at air conditioner compressor regulating valve N280. [Note: The bolts (arrows) have different lengths (the rear bolt may be longer). For this reason, it is important to ensure the correct allocation when installing.After securing air conditioner compressor, check routing of refrigerant lines (D) and (E). They must be inserted in brackets provided (if fitted, depending on engine).After securing air conditioner compressor, also check that refrigerant lines and corresponding brackets have adequate clearance to other components, ensuring sufficient distance between belt, bracket and pulley.]
11. Place poly V-belt on poly V-belt pulley 13Cylinder block, pulley end; Removing and installing poly V-belt.
12. Interrogate the event recorder of the front air conditioner operating and display unit, Climatronic control unit J255 and erase any faults displayed in "“Guided Fault Finding”" mode.

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