2004 Audi A6 / A6 Allroad / S6 / RS 6 (C5) Service & Repair Manual

1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 A/C SYSTEM, SAFETY PRECAUTIONS The following safety precautions have to be observed for these cooling aids (additional laws may apply for different countries) Empty (evacuate) refrigerant circuit first if the refrigerant circuit has to be opened during service. See A/C REFRIGERANT SYSTEM (R - 134A), EVACUATING AND RECHARGING . The refrigerant must not come in contact with your skin. If refrigerant should escape although all safety precautions were observed, do not inhale refrigerant/air mixture. The subassemblies and lines of the air conditioner are filled with 1.1.1.2 Tetrafluoroethane (CF 3 -CH 2 F or CH 2 F-CF 3 ) This refrigerant is currently known as R134a, H-FKW 134a, SUVA 134a and KLEA 134a (different names may apply to different countries.  Refrigerant R-134a replaces the refrigerant R-12 which is reported to have harmful effects on the earth's ozone layer.  R-134a and R-12 systems are similar in design but there are very important differences in the refrigerants, lubricating oils, service equipment and A/C system components. Reason: If refrigerant R134a is released into the environment, it enhances the green house effect. NOTE:  Compared to R12, R134a has a substantially lower green house effect.  Because R-134a does not contain chlorine atoms, the major catalyst in ozone depletion, R-134-a has no ozone depletion potential. The ozone depletion in the upper atmosphere is only initiated by splitting carbon- chlorine bonds (e.g. properties of R12) WARNING:  Always use an Underwriter's Laboratory (UL) approved refrigerant recovery/recycling/recharging unit such as Kent-Moore ACR 4 , or equivalent, whenever discharging an R-134a A/C system.  As of January 1, 1992 any person who services a motor vehicle air conditioner MUST, by law, be properly trained and certified and use approved refrigerant recycling equipment. Technicians must complete an EPA approved recycling course to be certified.  State and Provincial governments may have additional requirements 2005 Audi Allroad Quattro 1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 FIXYOURCAR 3:57:53 PM Page 1 FIXYOURCAR 3:58:11 PM Page 1

Always wear hand and eye protection (gloves and goggles) when working around the A/C refrigerant system and switch on existing exhaust/ventilation systems. Reason: Unprotected body parts may freeze under intensive impact of refrigerant aid. If other body parts came in contact with refrigerant although all safety precautions were observed, flush body parts immediately for at least 15 minutes with cold water. Although refrigerant is not flammable, smoking, welding or soft or hard soldering is not permitted in a room aerated with refrigerant. Reason: The refrigerant gas is chemically split via the high temperature of the open flame or via the hot body creating a poisonous gas. Breathing poisoning refrigerant vapors leads to irritated eyes, nose and throat. Drain refrigerant circuit Climate control with refrigerant R134a The refrigerant must be drained using an air conditioning service station and should not be released into the environment. The drained refrigerant will be locally recycled or is send to an environment-recycling place to the manufacturer (different or additional laws may apply in USA). After draining the refrigerant circuit, interrupt the voltage supply to A/C Clutch -N25- or A/C Compressor regarding air conditioning servicing. Always comply with state and local laws. WARNING:  The A/C system is filled with refrigerant which is under pressure.  Make sure to have an eye-flushing bottle available. WARNING:  Refrigerant must not come in contact with your skin. If liquid refrigerant has come in contact with your skin or eyes:  Do not rub skin or eyes.  Immediately flush with cool water for 15 minutes.  Rush to a doctor or hospital.  Do not attempt to treat yourself.  The doctor must be informed, which type of refrigerant caused the freezing. 2005 Audi Allroad Quattro 1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 FIXYOURCAR 3:57:53 PM Page 2

Regulator Valve -N280-. For this, depending on vehicle equipment disconnect harness connector of A/C Pressure Switch -F129-/High Pressure Sensor -G65- or disconnect harness connector on compressor (to -N25- /to -N280-) Reason: Disconnecting the voltage supply prevents accidental compressor operation via -N25- with the A/C system discharged. The A/C Compressor Regulator Valve -N280- is not activated and the compressor runs at idle. This compressor is built in such way, that the components are lubricated at idle via an internal oil circuit (as long as enough oil is in compressor). Work on refrigerant circuit Work on refrigerant system should only be carried out in a properly ventilated workshop. Ensure that within 5 meters circumference there are no working-pits, basement staircases or shafts. Switch on existing/ventilation systems when working on the refrigerant system. Reason: The exiting refrigerant is colorless, odorless and heavier than air and therefore displaces oxygen. Should refrigerant escape although all safety precautions were observed, a previously unrecognizable danger of suffocation exists in non vented rooms and working pits. WARNING:  Switch on existing exhaust/ventilation systems when working on the refrigerant system.  Work in a well ventilated area because refrigerants are heavier than air, displace oxygen and may cause suffocation in areas of poor air circulation, like under the car.  Avoid breathing refrigerant vapors. Exposure may irritate eyes, nose and throat.  Always wear hand and eye protection (gloves and goggles) when working around the A/C refrigerant system.  Do not expose any component of the A/C system to high temperatures (above 80 ° C/176 ° F) or open flames. Excessive heat will cause a pressure increase which could burst the system.  The escaping refrigerant/air mixture should not be inhaled, but should be sucked out via an existing exhaust ventilation system. WARNING:  Keep refrigerant containers stored below 50 ° C (12 2 ° F) and never drop from high places. DO NOT warm refrigerant containers with an open flame. If refrigerant needs to be warmed, place the bottom of the tank in warm water. 2005 Audi Allroad Quattro 1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 FIXYOURCAR 3:57:53 PM Page 3

Immediately plug open connections on A/C system when servicing the system. Reason: Moisture enters the A/C system and components when system was opened for longer period of time. An A/C system that was open for a longer period of time cannot be filled again without replacing components of the  Keep refrigerant away from open flames because poisonous gas will be produced if it burns. Do not smoke when refrigerants are present for the same reason.  Electric welding near refrigerant hoses causes R-134a to decompose from ultraviolet light. Discharge system before electric welding.  Pressurized R-134a refrigerant in the presence of oxygen may form a combustible mixture. Never introduce compressed air into any closed R-134a container (full or empty), A/C component or piece of service equipment.  DO NOT exceed the maximum rated capacity of refrigerant containers. Never fill a container to more than 60% of its gross weight rating (for example, 18 lb. in a 30 lb. container.) Without sufficient room for expansion of R-134a (gas cushion), the container could explode when the temperature rises causing serious injury.  Do not steam clean condensers or evaporators. Use only cold water or compressed air. CAUTION:  R-12 and R-134a refrigerants are NOT compatible. Never add R-12 refrigerant to an R-134a system or R-134a refrigerant to an R-12 system. If the refrigerants are mixed, total system contamination will occur and compressor failure may result.  Refrigerant oils used for the R-134a system and R-12 system are NOT compatible. Use only the specified synthetic oil (Polyalkylene Glycol/PAG) for the R-134a refrigerant system. DO NOT use R-12 system oil in an R-134a system or R-134a system oil in an R-12 system. If the refrigerant oils are mixed, system contamination will occur and compressor failure may result.  R-134a refrigerant system oil (PAG oil) absorbs moisture very rapidly. Moisture combines with the refrigerant to form acids which will damage the system. Use only the specified oil from a sealed container and ALWAYS reseal the oil container immediately after use. DO NOT use oil if it has become contaminated with moisture or if container has been left open.  Immediately plug open connections on A/C components to prevent dirt and moisture contamination. Likewise, DO NOT remove new component from packaging until ready to install. Immediately tighten component connections after installation. 2005 Audi Allroad Quattro 1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 FIXYOURCAR 3:57:54 PM Page 4

system. Paint work on vehicles with A/C systems Surface temperatures of 80 ° C should not be exceeded in the drying-oven or the pre-warm zone during the paint job. Reason: A high positive pressure occurs in the system when heating, this can lead to an explosion of the system. CAUTION:  Always use separate refrigerant recovery/recycling/recharging servicing equipment for R-12 and R-134a systems. DO NOT use one piece of equipment for both R-12 and R-134a systems. The residual traces of refrigerant will contaminate and damage the equipment. Servicing equipment includes recovery/recycling/recharging unit, charging station, vacuum pump, manifold gauges, etc.  DO NOT use R-12 servicing equipment on R-134a systems or R-134a equipment on R-12 systems or damage to both the vehicle A/C system and servicing equipment may result. Use only equipment designed to meet Society of Automotive Engineers (SAE) standards.  R-134a and R-12 systems use different size service fittings. NEVER use adapters to convert an R-12 fitting to R-134a size or R-134a fitting to R-12 size.  R-134a and R-12 A/C components including compressor, hoses, O- rings, evaporator, condenser, receiver-drier, etc. are NOT interchangeable. Components of the R-134a system are identified by lettering "R-134a" or by a green label (or stripe). In addition, a label on the evaporator housing (below plenum chamber) identifies which type of refrigerant is used. Use only the correct system component for each refrigerant type. CAUTION:  Always replace damaged and/or leaking A/C system components. Do not attempt repair by soldering, brazing or welding.  Work area must be extremely clean when working on A/C system components.  Use only tools, equipment and parts specified for use with R-134a.  Switch on existing exhaust/ventilation systems when working on the refrigerant system.  Discharge A/C system using refrigerant recovery/recycling/recharging unit Kent-Moore ACR 4 , or equivalent, before removing any A/C system component. See A/C REFRIGERANT SYSTEM (R - 134A), DISCHARGING . 2005 Audi Allroad Quattro 1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 FIXYOURCAR 3:57:54 PM Page 5

Do not attempt repair on filled air conditioning systems by soldering, brazing or welding. This pertains also for welding and soldering work on the vehicle, in the event that parts of the climate control system may heat up Reason: A high positive pressure occurs in the system when heating, this can lead to an explosion of the system. Corrective action: Discharge A/C refrigerant system. See A/C REFRIGERANT SYSTEM (R - 134A), DISCHARGING . A/C SYSTEM, GENERAL REPAIR GUIDELINES The refrigerant circuit of the A/C system must not be discharged and opened unless this is necessary because of safety precautions or unless components of the refrigerant circuit of the A/C system have to be to replaced. See A/C REFRIGERANT SYSTEM \(R - 134A\), DISCHARGING . When performing all other usual vehicle repair work, the refrigerant circuit of the A/C system should also remain closed. Servicing operations that can be carried out on the heating and air conditioning system without opening the refrigerant circuit, are described in REFRIGERANT CIRCUIT, SERVICING . For servicing operations to A/C systems that require discharging the refrigerant circuits. See A/C REFRIGERANT SYSTEM (R - 134A), DISCHARGING . Service work on A/C systems that pertains to the refrigerant circuit should only be carried in workshops equipped with suitable workshop tools.  After emptying A/C refrigerant, disconnect power supply from A/C clutch -N25- (e.g. disconnect harness connector from A/C pressure switch -F129-) to prevent accidental compressor operation with A/C system discharged.  Always replace O-rings, DO NOT reuse. Use only the correct size and type of O-rings specified for use with R-134a refrigerant. Lubricate O- ring with refrigerant oil before installing.  Always reinstall cap(s) over A/C service valve(s). NOTE: Always replace damaged and/or leaking A/C system components. Do not attempt repair by soldering, brazing or welding. NOTE: The connections for switches mentioned in this Repair Manual are provided with a valve that closes automatically when the switches/sensors are unscrewed and removed. These switches can be replaced even though the refrigerant circuit is fully charged. 2005 Audi Allroad Quattro 1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 FIXYOURCAR 3:57:54 PM Page 6

A/C REFRIGERANT R-134A, PROPERTIES Commercial designation Obtain R-134a refrigerant (tetrafluoroethane) from a local A/C supplier under one of the following names:  H-FKW 134a  SUVA(R) 134a  KLEA 134a Color Refrigerant R-134a is colorless and is invisible as a gas. Only the layer between the gas and the fluid is visible (fluid level in the tube of the cylinder or bubbles in the sight glass in the fluid reservoir). R-134a when viewed through a sight glass (if installed) may appear milky due to the mixing of refrigerant and lubricating oil (PAG oil). Airborne properties Escaped refrigerant gases are heavier than air and will gather first in low places, like under the car. Solubility of refrigerant oil A required special refrigerant oil Polyalkylene Glycol (PAG) synthetic oil is used to lubricate cylinder walls and bearings and enters the A/C system to some degree. This oil is NOT compatible with mineral based oils used in R-12 systems. Effects on the environment Because R-134a does not contain chlorine atoms, the major catalyst in ozone depletion, R-134a has no ozone depletion potential. R-134a does not cause smog and has a considerably lower global warming potential (greenhouse effect) than R- 12 refrigerant. Nonetheless, do not release R-134a into the environment and always recover/recycle using approved service equipment. Toxicity NOTE: R-134a refrigerant is packaged in different containers. Use only R-134a that comes in containers having correct types of service fittings. WARNING: R-134A refrigerant gas displaces oxygen and may cause suffocation in areas of poor air circulation. NOTE: R12 refrigerant systems use mineral oils which are not dissolved by R-134a refrigerant and are unusable. 2005 Audi Allroad Quattro 1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 FIXYOURCAR 3:57:54 PM Page 7

Refrigerant R-134a is non-toxic up to a temperature of 101 ° C (214 ° F) and is safe when handled and used properly. Above 101 ° C (214 ° F), gas pressure is above 39.5 bar (573 psi) and R-134a begins to decompose into poisonous gases (hydrogen fluoride, carbonyl fluoride and fluorine). These gases give adequate warning of their presence since they cause irritation of the mucous membrane (throat). Refrigerant R-134a gas has no effect on foodstuffs; it does not poison food or make it inedible. Temperature/pressure relationship In a partially charged refrigerant container, refrigerant gas comes to the surface, which under particle formation becomes fluid. This occurs under pressure and is know as gas pressure. Similar to R-12 refrigerant, the gas pressure of R-134a is temperature dependent. R134a TEMPERATURE/PRESSURE RELATIONSHIP Effects on plastics Refrigerant R-134a will deteriorate some plastics. When system temperature drops, these plastics can be deposited at the expansion valve or restrictor causing blockage. Therefore, when making system repairs, use only genuine Audi replacement parts which are specified for use with R-134a refrigerant. Temperature in ° C (° F) Pressure in bar (psi) -30 (-22) 0.0 (0.0) -20 (-4) 0.3 (4.4) -10 (14) 1.0 (14.5) 0 (32) 1.9 (27.5) 10 (50) 3.1 (45.0) 20 (68) 4.7 (68.2) 30 (86) 6.7 (97.2) 40 (104) 9.1 (132.0) 50 (122) 12.2 (177.0) 60 (140) 15.8 (229.2) 70 (158) 20.2 (293.0) WARNING: Paint repairs on vehicles with A/C:  While performing body/paint repairs involving the use of preheating or drying ovens, do not expose any component of the A/C system to temperatures above 80 ° C/176 ° F.  Excessive heat will cause a pressure increase which could burst the system.  Temperature/pressure chart, see A/C REFRIGERANT SYSTEM, PRESSURE AND TEMPERATURE RELATIONSHIPS . 2005 Audi Allroad Quattro 1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 FIXYOURCAR 3:57:54 PM Page 8

Effects on metal In its pure state, refrigerant R-134a is chemically stable and will not attack iron or aluminum. However, the mixture of R-134a and PAG oil may deteriorate certain metals (copper) which could lead to blockage, leaks or deposits on the compressor piston. Therefore, when making system repairs, use only genuine Audi replacement parts which are specified for use with R-134a refrigerant. Critical temperature/critical pressure R-134a refrigerant will remain chemically stable up to a pressure of 39.5 bar (573 psi). This corresponds to a temperature of 110 ° C (230 ° F). Above this temperature the refrigerant deteriorates. See CRITICAL TEMPERATURE/CRITICAL PRESSURE . Water solubility Liquid R-134a refrigerant will absorb only very minute quantities of moisture. However, R-134a vapor can absorb large amounts of moisture. Water in the system forms ice in the expansion valve or restrictor causing the system to stop cooling. In addition, moisture combines with the refrigerant to form acids which will damage the system. Flammability R-134a refrigerant is not flammable. In fact, it tends to inhibit combustion and has a fire extinguishing effect. However, a flame or glowing hot surface, as well as ultraviolet light (from electric welding), will decompose the refrigerant into poisonous gases (hydrogen fluoride, carbonyl fluoride and fluorine). These gases give adequate warning of their presence since they cause irritation of the mucous membrane (throat). R-134a can become flammable at pressures above ambient pressure in conjunction with air concentrations greater than 60% by volume. Refrigerant containers There must be pressure space available in the fluid area of the container. At increasing temperatures the fluid expands, the space filled with vapor becoming smaller. At a specific point there will only be fluid in the container. Beyond this point, only a slight increase in temperature will result in a very high pressure in the container. Leak detection WARNING:  Without sufficient room for expansion of R-134a (gas cushion), the container could explode when the temperature rises causing serious injury.  DO NOT exceed maximum rated capacity of refrigerant containers. Never fill a container to more than 60% of its gross weight rating (for example, 18 lb in a 30 lb container.) 2005 Audi Allroad Quattro 1998-2004 HVAC Air Conditioning - A6, Allroad, RS6 & S6 FIXYOURCAR 3:57:54 PM Page 9

2004 Audi A6 / A6 Allroad / S6 / RS 6 (C5) Service & Repair Manual

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