Evaporator Core: Service and Repair
Evaporator, A/C Unit Installed
Special tools, testers and auxiliary items required
• Pliers for Unplugging A/C Pipes (T40147)
• Sturdy carpet knife with a point; the blade must be secure and the handle must be strong.
• If the evaporator is not available as a single part, the evaporator must be replaced with the evaporator housing. Remove and install the evaporator housing. Refer to Electronic Parts Catalog (ETKA) and => [ Evaporator Housing ] Evaporator Housing.
Removal
The evaporator is available as a single part. Refer to Electronic Parts Catalog (ETKA).
- Move the front seats as far back as possible.
- Drain the refrigerant circuit.
- Remove the expansion valve. Refer to => [ Expansion Valve ] Expansion Valve.
- Remove the retaining plate - A - from the refrigerant lines - B, C -.
- Remove the driver footwell vent. Refer to => [ Air Guide to Left Footwell Vent - Driver Side ] Air Guide to Left Footwell Vent - Driver Side.
- Remove the steering column.
- Remove the pedal assembly.
- Release the retaining tab - B - and detach the cover - A - for the refrigerant lines on the evaporator housing - C -.
• During the further steps, ensure that the sealing lip - E - on the evaporator housing is not damaged.
- Remove the butyl mat - A - from the refrigerant lines - A, B -.
- Disconnect the refrigerant lines - A, B - at the locations marked by - C - with the (T40147).
- Bend the remaining refrigerant line - A - at the evaporator backward in the direction of travel until the evaporator can be removed from the housing.
- Remove the glove compartment.
- Remove the footwell vent on the front passenger side. Refer to => [ Right Footwell Vent Air Guide - Front Passenger Side ] Right Footwell Vent Air Guide - Front Passenger Side.
- Remove the air intake housing. Refer to => [ Air Intake Housing ] Air Intake Housing.
- Cut the housing wall - A - on the right side of the evaporator housing using a sharp knife (for example, a sturdy carpet knife with a point; the blade must be secure and the handle must be strong) along marked cutting line - B - from the A/C unit.
• During the further steps, ensure that the sealing lip on A/C unit - C - is not damaged when cutting out housing wall - A -.
• If the connection between the housing wall - A - and the A/C unit cannot be disconnected with a carpet knife because the material at the cutting line - B - is too thick, the connection at the cutting line - B - can be carefully disconnected for example with a Window cutter (V.A.G 1561A) and a blade, offset (V.A.G 1561/4) or a Saw blade, 63mm (V.A.G 1561/25). Do not damage the sealing lip on A/C unit - C -.
• If the evaporator was already replaced earlier (separating wall glued in instead of housing wall - A -), cut out this separating wall at the adhesive line (marked cutting line - B -) with the Window cutter (V.A.G 1561A). After removal of the evaporator, carefully remove adhesive residue from the evaporator housing.
- Remove the evaporator - B - in the - direction of the arrow - from the evaporator housing - A -.
- Attach a thin string - F - to each disconnected refrigerant line - B, C -.
• String - F - serves as an insertion aid for the new refrigerant lines to be installed.
- Coat the pass-throughs - D, E - in the grommet - A - for the refrigerant lines - B, C - with lubricant.
Risk of damage to the grommet.
• A damaged grommet can only be replaced with the A/C unit removed.
• With a second technician, push the refrigerant lines out of the grommet into the interior.
- Turn the disconnected refrigerant line - B - in the - direction of the arrow -, detach from the grommet, and remove from the evaporator housing - A -.
- Turn the disconnected refrigerant line - C - in the - direction of the arrow -, detach from the grommet, and remove from the evaporator housing - A -.
- Detach the string for aiding insertion at the refrigerant lines.
Installation
Installation is done is reverse order, observe the following:
• Tightening specification, refer to => [ Air Distributor Housing, Evaporator Housing, Evaporator ] Overhaul.
• New refrigerant lines - C, D - are provided with protective caps - A, B, E, F - to prevent the connection from being damaged during installation and to prevent the penetration of dirt.
• For noise insulation, the refrigerant lines are wrapped with a butyl mat - G, H -. Ensure that the butyl mat is not damaged or pinched.
• The refrigerant lines are installed with the protective caps through the grommet to the plenum chamber.
- Attach the string for aiding insertion to the new refrigerant lines - B, C -
• Ensure that the strings are not twisted in the installation shaft of the A/C unit.
- Coat the refrigerant lines, protective caps, and pass-throughs - D, E - in the grommet - A - with lubricant.
Risk of damage to the grommet.
• A damaged grommet can only be replaced with the A/C unit removed.
• With a second technician, push the refrigerant lines through the grommet toward the outside.
- Insert the refrigerant line - A - (thin pipe) into the evaporator housing - C - and push it through the smaller opening into the grommet to the plenum chamber by turning in a counterclockwise direction.
- Insert the refrigerant line - B - (thicker pipe) into the evaporator housing - C - and push it through the larger opening into the grommet to the plenum chamber by turning in a counterclockwise direction.
- The second technician can facilitate insertion into the correct opening - E, D - of the grommet by carefully pulling on the string - F -.
- Arrange the refrigerant pipes - A, B - so that they do not interfere and are not damaged during installation of the evaporator.
- Check the evaporator housing - A - via the evaporator installation shaft for contamination and clean if necessary.
• Pay attention to left and right condensation water drains - D - in the A/C unit.
- The foam strips - B - applied to the evaporator - A - and the cover - E - must be glued to the periphery - check for damage.
- Check the connections - C, D - for contamination and damage.
- Install the cover on the correct side of the evaporator - A -.
• The cover is included in the evaporator repair kit. Refer to Electronic Parts Catalog (ETKA).
- Push the evaporator - A - with the cover - D - into the shaft of the evaporator housing - B - to the stop. The brackets - E - must engage.
• The foam strip - C - must not be damaged or become detached.
• In the case of a foam strip that is not properly glued on, there may be a reduction in A/C system performance.
- Remove the protective caps from the refrigerant pipes - A, B -.
- Check the refrigerant lines and the evaporator connections - E - for damage and contamination.
• Even slight damage (a scratch) or a little bit of dirt (a hair) can cause leakage at a connection.
• The O-ring seals are pre-installed on the refrigerant lines by the manufacturer.
• The refrigerant lines, the O-ring seals, the bracket, and the screw are contained in the evaporator repair kit. Refer to Electronic Parts Catalog (ETKA).
• Coat the O-ring seals lightly with refrigerant oil prior to installation. Refer to => [ Refrigerant Circuit O-rings ] Refrigerant Circuit O-Rings.
- Insert the refrigerant lines into the evaporator connections - E - to the stop.
- Install the retaining plate - F - and tighten the screw - G - by hand until it makes contact.
• The refrigerant lines must still be able to be rotated.
• The retaining plate and refrigerant lines must not be under stress.
- Install the retaining plate - A - on the refrigerant lines - B, C -.
- Install the expansion valve to align the two refrigerant lines. Do not tighten the screws. Refer to => [ Expansion Valve ] Expansion Valve.
- Check the support ring - E - for proper seating in the grommet.
• The brace at the support ring must point outward.
• Check the evaporator grommet on the plenum chamber bulkhead pass-through for proper seating.
• Water penetration into the passenger compartment if the grommet is damaged or not installed correctly.
- Tighten the screw - G -. Tightening specification, refer to => [ Air Distributor Housing, Evaporator Housing, Evaporator ] Overhaul.
- Install the expansion valve. Refer to => [ Expansion Valve ] Expansion Valve.
- Check the cover - A - and replace it in the case of damage.
• The retaining tab - G - must not be overstretched.
• The peripheral groove - F - in the cover must not be damaged.
- After replacement of the evaporator, the cover must be adjusted. Remove the separating wall - B - and front part of the guide - C - for this purpose.
- The rear part of the guide - D - must not be damaged.
- The retaining tab - J - must be beveled at the corner - H - as shown in the figure.
- Install the cover - A - on the evaporator housing and press it on until it engages audibly.
• Ensure that the foam and the butyl mat are not pinched when installing the cover.
• Even the smallest leak at the groove/spring connection - D, E - between the cover and the evaporator housing can cause whistling noises. Therefore, coat the connecting surfaces lightly with silicone grease, for example. Silicone grease. Refer to Electronic Parts Catalog (ETKA).
- Carefully cover the floor covering under the installation shaft for the evaporator (to protect the floor covering against possible contamination with the adhesive sealant).
- Clean the evaporator housing - B - and the cover - D - at the locations marked with - F - and - G - (and dry if necessary).
- Carefully seal the connecting points between the evaporator housing and the inserted separating wall with silicone sealing compound. Silicone sealing compound, refer to Electronic Parts Catalog (ETKA).
• If the connecting points between the A/C unit and the evaporator and separating wall are not properly sealed, condensation water from the A/C unit could leak into the footwell when cornering, for example.
- Remove any excess adhesive (the adhesive maybe only in the area - D - ); and remove any excess adhesive out of the groove - G -.
- Install the air intake housing. Refer to => [ Air Intake Housing ] Air Intake Housing.
- Install the footwell vent on the front passenger side. Refer to => [ Right Footwell Vent Air Guide - Front Passenger Side ] Right Footwell Vent Air Guide - Front Passenger Side.
- Install the glove compartment.
- Install the pedal assembly.
- Install the steering column.
- Evacuate and fill the refrigerant circuit.
After completion of the repair work, perform the following work on the control head using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function:
- Read out the event memory and erase any displayed entries.
- Perform the basic setting.
- Perform the output diagnostic test mode.
- Operate the A/C system after filling the refrigerant circuit. Refer to => [ A/C System, Operating After Filling Refrigerant Circuit ] A/C System, Operating After Filling Refrigerant Circuit.