Servicing refrigerant circuit in vehicles with compressor with regulating valve -N280 — AUDI

Notes:

The compressor is always driven with the engine running, it does not have a magnetic clutch. Therefore the engine must be only started with a correctly assembled refrigerant circuit. If, for example, the refrigerant pipes are not connected to the compressor, the compressor may become so hot when the engine is running that it is destroyed (by internal heating). The internal heating is caused by the compressor operating even at almost 0% delivery rate against a fixed resistance (sealed circuit).
To prevent the compressor being destroyed when the refrigerant circuit is empty, it is designed so that it resets to approx. 0% delivery rate and continues to be lubricated via an internal oil circuit with the oil remaining in the compressor.

Replacement compressors contain all the refrigerant oil required to fill the refrigerant circuit (at present 220 cm3or 245 cm3). Note the data relating to this on label attached to the compressor.

=> Parts List

=> Air Conditioner with Refrigerant R134a

HD = High-pressure side

ND = Low-pressure side

Regulating valve for air conditioner compressor -N280
Do not remove
Check actuation and function => Page
01-352

Note:

The -N280 is actuated by the -E87, it controls the pressure on the low pressure side of the refrigerant circuit

Compressor
O-ring seal for compressor:
for low-pressure connection:
23.8 mm; 2.4 mm.
for high-pressure connection:
11.1 mm; 1.8 mm.
Disconnecting and connecting refrigerant pipe to compressor =>Page
87-241
To protect the compressor the engine must only be started when the refrigerant circuit is completely assembled.
Removing ribbed belt.

=> Relevant Workshop Manual, Engine, Mechanical Components; Repair group 13

Removing and installing compressor => Page
87-244

The design of the compressor differs depending on the engine (attached on the right or left of the engine, 6 cyl. diesel or petrol engine)

=> Parts List

For the Audi allroad with 4.2l engine, the compressor is driven via a drive shaft and not via a belt => Page
87-70
After the installation of a new compressor or filling with fresh refrigerant oil (e.g. after blowing out the refrigerant circuit), turn the compressor 10 revolutions by hand before the first start to avoid damage to the compressor

Oil drain plug
A sealing ring is installed on the Denso compressor, always replace it
Tightening torque: 30 Nm
May only be unscrewed to drain refrigerant oil if compressor is removed.
Crank compressor with the magnetic clutch plate to accelerate extraction of refrigerant oil.

Compressor pulley/drive unit
Replace pulley =>Page
87-62
.
Checking, replacing compressor drive unit => Page
87-70

Pressure relief valve, 10 Nm
Do not remove

Connection with valve
Air conditioner high-pressure sender -G65
Removing and installing
=>Page
87-22
Checking signal
=>Page
01-342

Condenser
Renew O- ring seal
=>Page
87-254
Detaching and re-attaching refrigerant pipes => Page
87-254
Removing and installing condenser =>Page
87-259
.
Quantity of refrigerant R134a varies depending on type of condenser => Page
87-263

Cap
With seal
Must be fitted

Service connection
High-pressure side
For measuring, draining and filling with service station

Union in the refrigerant pipe
O- ring seal
10.8 mm; 1.8 mm.
Tightening torque: 15 Nm

Restrictor
Installed in the threaded connection -Item
11
-
O- ring seal
7.5 mm/1.5 mm
Replace restrictor with O- ring seal

Removing and installing =>Page
87-239
.
Apply a small amount of refrigerant oil to the O- ring seal before installing the restrictor.

Evaporator
Disconnecting and connecting refrigerant lines => Page
87-237
Removing and installing air conditioner => Page
87-267
.
Dismantling and assembling air-conditioner => Page
87-271
.
Different versions; on air conditioners from version "2" onwards the evaporator is 32 mm narrower than on version "1".

Service connection
Low-pressure side

Cap
With seal
Must be fitted

Reservoir
Removing and installing => Page
87-229
.