Evaporator Cleaning
Evaporator Cleaning
• Odors from the air conditioning system can be caused by various things, only a portion of these orders come from the evaporator and can be corrected by cleaning it with, for example, the Ultrasound A/C Cleaner (VAS 6189).
• Cleaning of the evaporator with the Ultrasound A/C Cleaner (VAS 6189) 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, refer to => [ Air Duct In Rear Heating & A/C Unit ] Air Duct In Rear Heating & 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 Display Control Head (E265) for this.
• Numerous procedures varying in their application and effect are available on the market for cleaning the evaporator. At this time Audi for example, had tested and approved cleaning the evaporator using the Ultrasound A/C Cleaner (VAS 6189A).
- Select path:
• Front (and rear) A/C system evaporator, cleaning using Ultrasound A/C Cleaner (VAS 6189A).
Causes of Odor
• Smell like burnt oil.
- Mostly forms in the engine compartment due to leaks on the engine or transmission.
• Sulphurous smell like exhaust.
- Due to leaks in the exhaust system.
- From exhaust gas entering passenger compartment for example, while driving in reverse (by driving through an exhaust cloud from same vehicle).
• Fishy smell like 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.
• Smell like a burned clutch.
• Evaporation from floor mats, decorative seat covers, etc.
• Rotten, mildewy, moldy or musty smell from plenum chamber.
- From accumulation and storing of various contaminants like leaves, tree needles etc. (for example, 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, refer to => [ Fresh Air Intake Housing ] Fresh Air Intake Housing.
• Odor from front heating & A/C unit (and/or rear).
• Odors for example, 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).
- Due to too much condensation water in A/C unit.
• Check the front A/C condenser water drain, refer to => [ Front Condensation Water Drain Hose ] Front Condensation Water Drain Hose (and/or rear => [ Condensation Water Drain ] Condensation Water Drain).
- From an old or severely soiled dust and pollen filter in front heating & A/C unit.
• Check dust and pollen filter, refer to => [ Dust and Pollen Filter ] .
- Due to deposits on evaporator fins.
• Clean evaporator with Ultrasound A/C Cleaner (VAS 6189A).
• 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 Ultrasound A/C Cleaner (VAS 6189A).
Front and Rear Evaporator Cleaning
Special tools, testers and auxiliary items required
• Ultrasound A/C Cleaner (VAS 6189A).
• Cleaning Fluid (VAS 6189/1)
• The evaporator in the rear A/C unit can currently be cleaned in the installed state only with the (VAS 6189). The evaporator is installed behind the A/C system under the left luggage compartment trim panel and is only accessible after removal of various components. For this vehicle, the air coming out of the rear A/C system is taken in via the air intake grille in the luggage compartment side trim panel on the left. Refer to => [ Air Duct In Rear Heating & A/C Unit ] Air Duct In Rear Heating & A/C Unit.
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).
• The odor can only be fixed by cleaning with the (VAS 6189A) if it originates in the evaporator.
- 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), refer to => [ Fresh Air Intake Housing ] Fresh Air Intake Housing.
- Remove dust and pollen filter and check it for odor and contamination, refer to => [ Dust and Pollen Filter ] .
• 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, refer to => [ Dust and Pollen Filter ] .
- Reseal opening on A/C unit through which dust and pollen filter was removed.
- Start the engine.
- Set operating mode to recirculated air mode on 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 (for example, temperature preselect Lo for front and rear) on the Climatronic Control Module (and on Rear A/C Display Control Head (E265) ).
- Close the windows and the sunroof.
- Set the Climatronic Control Module (and Rear A/C Display Control Head) to lowest fresh air blower speed and select the front instrument panel vent for air vent direction (set Rear A/C Display Control Head to Auto operating mode).
Cleaning
- Shake the bottle of (VAS 6189/1) and then fill the (VAS 6189A). Be sure to read the Operating Instructions that come with the (VAS 6189A).
- Place (VAS 6189A) in passenger side footwell.
- Start up the (VAS 6189A) (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 and A/C unit (beneath instrument panel in front passenger's footwell) is drawn in by the Fresh Air Blower.
• If evaporator in rear heating and A/C unit is to be cleaned in its own work procedure, place outlet hose of (VAS 6189A) 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 approximately 15 to 20 minutes, it is complete when vapor no longer escapes from outlet hose of the (VAS 6189A).
Finishing steps
- Switch (VAS 6189A) off.
- Open vehicle doors and air out vehicle at least 10 minutes.
- Remove the (VAS 6189A) from vehicle and clean it according to operating instructions.
- Switch off ignition.
- Install dust and pollen filter, refer to => [ Dust and Pollen Filter ] .