Air Conditioning: Overview Audi Q7 4L facelift

COMPONENT OVERVIEW

Note. Servicing refrigerant circuit, refer to REFRIGERANT CIRCUIT, SERVICING . All work or components marked with 1) can be repaired, replaced or performed in any workshop (work that does not pertain to refrigerant circuit). All refrigerant circuit components not marked with 1) as well as all refrigerant hoses and refrigerant lines can only be serviced or replaced in a workshop equipped with the necessary tools and in which the work procedures are performed by qualified personnel (refrigerant circuit must be discharged). Refer to General Information .

Note. This illustration shows in one overview the various refrigerant circuit components, the exact arrangement inside the vehicle depends on version and engine.

HD = High-pressure end

ND = Low-pressure end

1. A/C Compressor Regulator Valve -N280- Checking activation and function, refer to «A/C COMPRESSOR REGULATOR VALVE N280, CHECKING ACTIVATION SIGNAL»(ref-491706-S07386965152012073100000) 1) .
2. Compressor Removing compressor from bracket and re-installing in vehicles with 6 cylinder engine, refer to «COMPRESSOR, REMOVING AND INSTALLING ON BRACKET»(ref-491706-S32459619332012073100000) 1) . On an 8 cylinder, it is necessary to evacuate the refrigerant circuit in order to remove the A/C compressor from the bracket. Refer to «COMPRESSOR»(ref-491706-S23648515632012073100000) . When installing refrigerant lines/hoses and pertaining bracket, make sure there is a sufficient gap between belt, bracket and belt pulley. Depending on time period of production and on engine, compressor construction type may vary. At beginning of production, Denso compressors were installed. Refer to «Removal and Installation»(ref-491656-S28742911592012073100000) . These compressors are available as replacement parts with different oil fill capacities, therefore note capacity on compressor and the exact part number. The reason for the different oil capacities in the compressor for an otherwise identical refrigerant circuit lies in the design of the compressor itself, note these oil capacities. Too much oil in the circuit leads to higher pressures and reduces cooling performance of the system. Too little oil may lead to lubrication problems in the compressor. Depending on compressor type and design of refrigerant circuit (one or two evaporators), different refrigerant oil and refrigerant capacities are designated for the refrigerant circuit. Refer to «REFRIGERANT OIL CAPACITIES»(ref-491656-S35413708142012073100000) .
3. Compressor Belt Pulley/Drive Unit Different versions (depending on the engine). A/C Compressor Belt Pulley, 6 Cylinder TDI, removing and installing 1) ; refer to «COMPRESSOR BELT PULLEY»(ref-491706-S11817204772012073100000) . Ribbed Belt, 6 cylinder TDI, removing and installing 1) ; refer to «[For engine(s) CATA] Removal and Installation»(ref-491732-S16103088462012073100000) . For the correct ribbed belt allocation for 6 cylinder TDI. A/C Compressor Drive Unit, 8 cylinder FSI, removing and Installing, refer to «COMPRESSOR DRIVE UNIT»(ref-491706-S31001042832012073100000) (A/C Compressor, removing, refer to «COMPRESSOR»(ref-491706-S23648515632012073100000) ). NOTE: An overload safeguard is installed between the belt pulley/drive unit and driveshaft, this protects the compressor belt/engine in the event that the compressor is seized or does not move freely. If compressor is runs with resistance, overload safeguard interrupts power transmission to compressor. Rubber elements are installed between belt pulley/drive unit and compressor driveshaft, vibrations which may occur during compressor operation may be dissipated via these rubber elements (damper function at torque fluctuations). Depending on compressor type, different belt pulleys are installed on compressor. Refer to «COMPRESSOR BELT PULLEY»(ref-491706-S11817204772012073100000) .
4. Oil Drain Plug
5. High Pressure Relief Valve
6. Connection Without Valve
7. Refrigerant Temperature Sensor -G454- WARNING: The connection on which Refrigerant Temperature Sensor is installed does not possess a valve, therefore Refrigerant Temperature Sensor must only be removed with a discharged refrigerant circuit. Function and signal utilization, refer to «REFRIGERANT TEMPERATURE SENSOR -G454-, FUNCTION AND SIGNAL UTILIZATION»(ref-491706-S39856573832012073100000) . Not installed in all vehicles (depends on the engine, the version of the vehicle and when the vehicle was produced). Refer to the appropriate System Wiring information. NOTE: For example, installed in vehicles with a 6 cylinder TDI engine or an 8 cylinder engine through 10.2007. The refrigerant temperature sensor was discontinued as of November 2007 as a running change. On vehicles with the Comfort A/C system, make sure the Climatronic control module -J255- for the Comfort A/C system is installed. Vehicles with a 6 cylinder TDI engine or an 8 cylinder engine but without a refrigerant temperature sensor may only have the Comfort front control and display unit installed (part number 4L0 820 043, beginning with index letter K). If the vehicle has the Basis A/C system without a refrigerant temperature sensor, and the sensor is being displayed as a fault, then perform an adaptation to the Basis front A/C control head. It is not necessary to perform this on the Comfort A/C system because it has different versions of the front A/C control head. On vehicles wit the Basis A/C system, "Guided Fault Finding" displays the fault missing refrigerant temperature sensor and the evaluating of the refrigerant temperature sensor switches off (by entering "adaptation") of the Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding".
8. Condenser
9. Fluid Reservoir With Dryer Cartridge WARNING: The dryer cartridge may be removed only when the refrigerant circuit is empty. Fluid reservoir is a component of the condenser. Dryer cartridge can be replaced as an individual part.
10. Connection In Refrigerant Line WARNING: Bolts of the connection points must only be loosened when refrigerant circuit has been discharged. Depending on the version of the vehicle and the engine, these connection points may be present at different locations on the refrigerant lines.
11. Service Connection WARNING: Service connections (connection is not equipped with a valve) or the valves installed in them must only be removed when refrigerant circuit has been discharged. High pressure side. Different versions (with primary sealing valve or with Schrader valve) depending on refrigerant line, distinguishing characteristics. Refer to «ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT»(ref-491657-S07082631562012073100000) . For measuring, emptying and filling, refer to «Description and Operation»(ref-491657-S41221544792012073100000) . Depending on engine version, it may be necessary to remove different components in order to be able to connect to service coupling of the service station.
12. Cap With seal Always screw on
13. Connection With Valve Different installation locations depending on version and engine of the vehicle.
14. High Pressure Sensor -G65- 1) Removing and installing, refer to «HIGH PRESSURE SENSOR -G65»(ref-491706-S39118658192012073100000) . Checking signal, refer to «HIGH PRESSURE SENSOR G65, CHECKING PRESSURE SIGNAL»(ref-491706-S19004322942012073100000) .
15. Expansion Valve For evaporator in front heating & A/C unit (heating & A/C unit under instrument panel).
16. Evaporator Evaporator in front heating & A/C unit (under instrument panel). Removing and installing evaporator of front heating & A/C unit, refer to «FRONT EVAPORATOR»(ref-491706-S21896186102012073100000) .
17. Service Connection WARNING: Service connections (connection is not equipped with a valve) or the valves installed in them must only be removed when refrigerant circuit has been discharged. Low pressure side Different versions (with primary sealing valve or with Schrader valve) depending on refrigerant line, distinguishing characteristics. Refer to «ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT»(ref-491657-S07082631562012073100000) . For measuring and evacuating refer to «Description and Operation»(ref-491657-S41221544792012073100000) . Depending on engine version, it may be necessary to remove components in order to be able to connect to service coupling of the service station.
18. Cap With seal Always screw on
19. Pre-volume Is a component of refrigerant line to compressor. Pressure fluctuations are damped in the pre-volume. Not installed in all vehicles (depending on the engine and on the version of the vehicle).
20. Connection Of Refrigerant Line To Evaporator In Rear Heating & A/C Unit WARNING: The bolts of the connection point may only be loosened when the refrigerant circuit has been discharged. Only present on vehicles with a rear heating & A/C unit (optional equipment, installed under trim at left in luggage compartment). High pressure side
21. Connection In Refrigerant Line To Evaporator In Rear Heating & A/C Unit WARNING: Bolts of the connection points must only be loosened when refrigerant circuit has been discharged. Only present in vehicles with a rear A/C unit (optional equipment).
22. Expansion Valve At Evaporator In Rear Heating & A/C Unit For evaporator in rear heating & A/C unit (installed under left side luggage compartment lining). Only present in vehicles with a rear A/C unit (optional equipment).
23. Evaporator In Rear Heating & A/C Unit Only present in vehicles with a rear A/C unit (optional equipment).
24. Connection Of Refrigerant Line To Evaporator In Rear Heating & A/C Unit WARNING: The bolts of the connection point may only be loosened when the refrigerant circuit has been discharged. Only present in vehicles with a rear A/C unit (optional equipment). Low pressure side

Scheme 1

1. Circlip Remove carefully using a small screwdriver or needle-nose pliers (especially note belt pulley when doing this). Removing and installing, refer to «COMPRESSOR BELT PULLEY, VERSION 1»(ref-491706-S16806813942012073100000) . As of MY 07 and as a running change, A/C compressors with a drive plate and without an outer hex head are being installed. These A/C compressors also have circlips with a rubber disc vulcanized on to them are installed. This rubber disc replaces the plastic disc which could be glued on up to then (not present on all compressors). Refer to «COMPRESSOR BELT PULLEY, VERSION 1»(ref-491706-S16806813942012073100000) .
2. Drive Plate Tightening specification 35 Nm. Depending on production time period, drive plates with 3 holes (as shown) or one outer hex head on the front side are installed. Versions having the outer hex head with a circlip but without a rubber disc are still being installed until further notice. Attached to compressor input shaft. With overload safeguard, triggers when torque is too-high (e.g. compressor produces friction) and belt pulley runs freely without driving the compressor. Removing and installing, refer to «COMPRESSOR BELT PULLEY, VERSION 1»(ref-491706-S16806813942012073100000) . A plastic washer may be glued on, depending on time period of production, refer to «COMPRESSOR BELT PULLEY, VERSION 1»(ref-491706-S16806813942012073100000) .
3. Circlip Replace Install on proper side (level side to compressor). Removing and installing, refer to «COMPRESSOR BELT PULLEY, VERSION 1»(ref-491706-S16806813942012073100000) .
4. Spacer Dimension: 17.5 x 10 x 3 mm
5. Rubber Element 6x, install on proper side, refer to «COMPRESSOR BELT PULLEY, VERSION 1»(ref-491706-S16806813942012073100000) . Decouples belt pulley from compressor driveshaft, damps vibrations and noise. For installation, lightly coat rubber elements, e.g. with tire mounting paste or a soap solution (as a lubricant).
6. Belt Pulley Belt pulley is made of plastic and is sensitive to impact, therefore handle it with special care. Removing and installing, refer to «COMPRESSOR BELT PULLEY, VERSION 1»(ref-491706-S16806813942012073100000) .
7. Compressor Different versions are installed, depending on engine version and country version of vehicle. Clean compressor flange before sliding on pulley.