A/C System Evaporator, Cleaning

A/C System Evaporator, Cleaning

• Cleaning of the evaporator is described only for the evaporator installed in front heating & A/C unit. On vehicles with a rear heating & A/C unit, the evaporator in rear heating & A/C unit is supplied with a small amount of cleaning solution and cleaned as well when the evaporator in front heating & A/C unit is being cleaned. If it should be necessary to clean the evaporator in rear heating & A/C unit in an additional work procedure, then proceed in the same way as for cleaning evaporator in front heating & A/C unit. To do this, make sure that the air from rear heating & A/C unit is drawn in via the air grate in the left side luggage compartment lining => [ Air Duct in Rear Heating and A/C Unit ] Air Ducts in and to Front and Rear Heating and A/C Unit. The air vent temperature for rear heating & A/C unit and speed for Rear Fresh Air Blower (V80) can be adjusted via Rear A/C Control Head (Climatronic) (E265) for this.

Possible cause for odors

• Odor from burned oil.

- Occurs mostly in engine compartment from a leak on the engine or transmission.

• Sulphurous odor from exhaust gas.

- From leak on the exhaust system.

- From exhaust gas entering passenger compartment e.g. while driving in reverse (by driving through an exhaust cloud from same vehicle).

• Fishy odor from coolant.

- From leak at cooling system of engine or of A/C system heater core.

• If fishy odor from front A/C system vents is detected also in recirculated air mode as well as in fresh air mode, check heater core of front heating & A/C unit for proper seal.

• Odor from a scorched clutch

• Emanations from floor mats, subsequently installed decorative seat covers etc.

• Rotten moldy odor from plenum chamber.

- From accumulation and storing of various contaminants like leaves, tree needles etc. (e.g. in plenum chamber)

- From water which cannot flow out of the plenum chamber or fresh air intake housing.

• Check water drains of plenum chamber and of A/C system fresh air intake housing => [ Fresh Air Intake Housing ] .

• Odor from front heating & A/C unit (and/or rear).

• Odors e.g. originating in front 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 at front heating & A/C unit only in fresh air mode or recirculated air mode, the cause is not in the front heating & A/C unit in most cases.

• If heater core is not sealed tightly, the odor may be of leaking coolant depending on temperature setting (air is not continuously flowing through heater core).

- From excessive water condensation in heating and A/C unit.

• Check condensation water drain of front heating & A/C unit => [ Front Water Drain Hose ] (and/or rear => [ Rear Water Drain Hose ] ).

- From an old or severely soiled dust and pollen filter in front heating & A/C unit.

• Check dust and pollen filter.

- From deposits on evaporator lamellae.

• Clean evaporator using ultrasonic HVAC cleaning system (VAS 6189).

Front (and rear) A/C system evaporator, cleaning using ultrasonic HVAC cleaning system (VAS 6189)

• Odors from the A/C system can have various causes, only a portion of these odors originate in the front (and/or rear) A/C system evaporator and can therefore be eliminated by cleaning the evaporator using ultrasonic HVAC cleaning system (VAS 6189).

Cleaning evaporator

• 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.

Tools required

• Ultrasonic HVAC cleaning system (VAS 6189)

• Cleaning fluid (VAS 6189/1).

Preparation

- Check whether the odor actually originates in the A/C system evaporator by switching from fresh air mode to recirculated air mode (only possible in front heating & A/C unit).

• Only when the odor originates in the evaporator can it be eliminated by cleaning using the ultrasonic HVAC cleaning system (VAS 6189).

- Check fresh air intake shaft of A/C system, plenum chamber and the water drain valves installed there and clean them if necessary (only on front heating & A/C unit) => [ Fresh Air Intake Housing ] .

- Remove dust and pollen filter and check it for odor and soiling.

• On this vehicle, the dust and pollen filter is installed between Fresh Air Blower (V2) and evaporator in front heating & A/C unit, therefore it must be removed for the cleaning.

- Clean the installation compartment for dust and pollen filter of front heating & A/C unit of leaves, dust and other contaminants.

- Close opening again on heating and A/C unit over which the dust and pollen filter was removed.

- Start engine.

- Set operating mode "recirculated air mode" on front A/C control head Climatronic Control Module (J255) and switch off compressor "Econ mode".

- Open instrument panel vents (and vents in "B" and " C" pillars, if present) and set the lowest possible temperature for driver's and front passenger's sides (e.g. temperature preselect "Lo " for front and rear) on front A/C control head Climatronic Control Module (J255) (and on Rear A/C Control Head (Climatronic) (E265)).

- Close vehicle windows and sunroof.

- Set the front A/C control head Climatronic Control Module (J255) (and Rear A/C Control Head (Climatronic) (E265)) to lowest fresh air blower speed and select the front "instrument panel vent" for air vent direction (set Rear A/C Control Head (Climatronic) (E265) to operating mode "Auto").

Cleaning

- Shake the bottle of cleaning fluid (VAS 6189/1) and fill it into ultrasonic HVAC cleaning system (VAS 6189), note the ultrasonic HVAC cleaning system (VAS 6189) operating instructions when doing this.

- Place the ultrasonic HVAC cleaning system (VAS 6189) in the front passenger's footwell.

- Start up the ultrasonic HVAC cleaning system (VAS 6189) (according to operating instructions) and route the outlet hose belonging to it so that the vapor escaping via the recirculated air opening of the front heating & A/C unit (beneath instrument panel in front passenger's footwell) is drawn in by the Fresh Air Blower (V2).

• If evaporator in rear heating & A/C unit is to be cleaned in its own work procedure, place outlet hose of ultrasonic HVAC cleaning system (VAS 6189) during the second work procedure in such a way that the steam emitted is drawn in via air grate in left side luggage compartment lining.

- Close vehicle doors.

• Cleaning procedure lasts approx. 15 to 20 minutes, it is complete when vapor no longer escapes from outlet hose of ultrasonic HVAC cleaning system (VAS 6189).

Final procedures

- Switch off the ultrasonic HVAC cleaning system (VAS 6189).

- Open vehicle doors and ventilate vehicle for a minimum of 10 minutes.

- Remove ultrasonic HVAC cleaning system (VAS 6189) from vehicle and clean it according to the operating instructions.

- Switch off ignition.

- Install dust and pollen filter.