S6 Quattro Sedan V10-5.2L (BXA) (2007)
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Evaporator Core: Procedures
A/C System Evaporator, Cleaning Using Ultrasonic HVAC Cleaning System VAS 6189
NOTE: Odors from the A/C system can have various causes, only a portion of these odors originate in the A/C system evaporator and therefore can be
eliminated by cleaning the evaporator using ultrasonic HVAC cleaning system VAS 6189.
Possible cause for odors
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Odor from burned oil.
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Occurs mostly in engine compartment from a leak on the engine or transmission.
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Sulphurous odor from exhaust gas.
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From leak on the exhaust system.
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From exhaust gas entering passenger compartment e.g. while driving in reverse (by driving through an exhaust cloud).
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Fishy odor from coolant.
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From leak at cooling system of engine or of A/C system heater core.
NOTE: If fishy odor is detected also in recirculated air mode as well as in fresh air mode, check A/C system heater core for proper seal.
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Odor from a scorched clutch
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Emanations from floor mats, subsequently installed decorative seat covers etc.
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Rotten moldy odor from plenum chamber.
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From accumulation and depositing of various contaminants like leaves, tree needles etc.
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From water which cannot flow out of the plenum chamber or air intake housing.
NOTE: Check water drains of plenum chamber and of air intake housing.
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Odor from the heating and A/C unit.
NOTE:
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Odors originating in heating and A/C unit can mainly be detected in fresh air mode as well as in recirculated air mode. If there is a complaint
of odor while in fresh air mode or recirculated air mode only, the cause is not in the heating and A/C unit in most cases.
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If heater core is leaking, the odor of the escaping coolant can be detected even in fresh air mode as well as in recirculated air mode (heater core
has continuous air flow).
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From excessive water condensation in heating and A/C unit.
NOTE: Check both condensation water drains.
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From an old or severely soiled dust and pollen filter.
NOTE: Check dust and pollen filter.
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From deposits on evaporator lamellae.
NOTE: Clean evaporator using ultrasonic HVAC cleaning system VAS 6189.
Cleaning evaporator
NOTE: Cleaning of the evaporator using the ultrasonic HVAC cleaning system VAS 6189 is demonstrated in the VW - Audi TV broadcast no. 201
Audi Service Net VW - Audi TV archive broadcast no. 201.
Required tools
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Ultrasonic HVAC cleaning system VAS 6189
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Cleaning fluid VAS 6189/1.
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Standard vacuum cleaner and suction nozzle with bush VAS 6288.
Preparation
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Check whether the odor actually originates in the A/C system evaporator by switching from fresh air mode to recirculated air mode.
NOTE: Only when the odor originates in the evaporator can it be eliminated by cleaning using the ultrasonic HVAC cleaning system VAS 6189.
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Check plenum chamber and the water drain valves installed there and clean them if necessary.
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Remove dust and pollen filter and check it for odor and soiling.
NOTE: On this vehicle, the dust and pollen filter is installed between Fresh Air Blower V2 and evaporator, therefore it must be removed for the
