S4 V8-4.2L (BHF) (2004)
Expansion Block/Orifice Tube: Service and Repair
Receiver or Reservoir and Restrictor, Replacing
Receiver or Reservoir and Restrictor, Replacing
Replacing after flushing refrigerant circuit, e.g. on account of ingress of moisture (refrigerant circuit open for lengthy period) or contamination
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Discharge refrigerant circuit.
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Remove compressor.
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Rectify cause of trouble.
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Clean (flush) refrigerant circuit with compressed air and nitrogen.
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Examine expansion valve for dirt or corrosion and replace if necessary.
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Remove oil drain plug from compressor.
NOTE: The oil drain plug of "Denso/Nippondenso" compressors is equipped with an oil seal instead of an O-ring and this is always to be
replaced.
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To accelerate drainage of refrigerant oil, rotate compressor by way of clutch plate of A/C clutch for example.
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Pour old refrigerant oil out of compressor.
NOTE: Disposal of old refrigerant Audi-ServiceNet, Handbooks, HSO Environment 2
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Then fill compressor with quantity of fresh refrigerant oil corresponding to quantity of refrigerant oil in replacement compressor.
NOTE:
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Use different refrigerant oils and quantities for the various compressors.
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To ensure compressor lubrication on start-up, at least 80 cu.cm of refrigerant oil must be poured into the compressor. The remainder can be
added for example to the new reservoir or receiver.
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If dirt has penetrated into the compressor with the refrigerant circuit open (e.g. after an accident), compressor is to be replaced.
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Replace receiver or reservoir and restrictor.
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Assemble, evacuate and charge refrigerant circuit.
Replacing without the need for flushing refrigerant circuit with compressed air and nitrogen (e.g. in the event of accident damage); no escape
of refrigerant and no ingress of moisture and dirt into circuit
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Discharge refrigerant circuit.
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Replace restrictor.
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Remove receiver or reservoir.
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Remove dirt from receiver or reservoir.
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Weigh receiver or reservoir removed.
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Add refrigerant oil to new receiver or reservoir until weight of component removed has been attained.
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Install new receiver or reservoir.
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Assemble, evacuate and charge refrigerant circuit.