Audi A4: Reservoir
The reservoir collects the vaporized and gaseous mixture
coming from the evaporator to ensure the compressor only
receives gaseous refrigerant. Gaseous refrigerant is formed from
the vapor.
The refrigerant oil flowing in the circuit is not retained
in the reservoir as it has an oil drilling.
Moisture which has entered the refrigerant circuit during
repairs will be collected by a filter (desiccant bag) in the
reservoir.
Gaseous refrigerant is extracted with oil by the A/C
compressor.
Note
- Replace the reservoir if refrigerant circuit has been open
for a long time (beyond the normal repair time) and moisture has
penetrated inside, or if required due to a specific complaint.
Refer to
→ Chapter "Refrigerant Circuit Components, Replacing".
- Remove the sealing plugs -A-
and -B- only immediately before
installing.
- A desiccant bag in an unsealed reservoir is saturated with
moisture after a short period of time and unusable.
- When installing, note arrow for direction of flow if
necessary.
Restrictor
Restrictor in Front of the Evaporator
The restrictor creates a constriction. This restriction
reduces the flow and creates high and low pressure sides in the
refrigerant circuit. Before the restrictor the refrigerant which
is under a higher pressure is warm. After the restrictor the
refrigerant which is under a low pressure is cold. Before the
restriction there is a strainer for contaminants and after the
restriction there is a strainer, to atomize the refrigerant
before it reaches the evaporator.
Note
- Arrow -A- on restrictor points
to the evaporator.
- Replace after each opening of the circuit.
- There are different versions, therefore pay attention to the
different customer service information sources. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit and (vehicle-specific
repair manual) and to the Parts Catalog .
Restrictor in Front of the High Voltage Battery Heat
Exchanger (Chiller)
The restrictor creates a constriction. This restriction
reduces the flow and creates high and low pressure sides in the
refrigerant circuit. Before the restrictor the refrigerant which
is under a higher pressure is warm. After the restrictor the
refrigerant which is under a low pressure is cold.
Note
- The illustration shows a refrigerant line
-A- with a fixed installed
restrictor -B- (without a strainer)
- The diameter of the illustrated variable orifice
-B- is approximately 0.7 mm.
Depending on the version of the refrigerant line this
constriction is either installed fixed in the refrigerant line
or only inserted. For the inserted version a strainer for
flowing deposits may be installed, which can be blocked by the
variable orifice.
- Before installing check for debris and if necessary clean or
replace.
- There are different versions, therefore pay attention to the
different customer service information sources. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit and (vehicle-specific
repair manual) and to the Parts Catalog.
Receiver/Dryer
The receiver/dryer collects the fluid drops and then directs
them in an uninterrupted stream to the expansion valve. Moisture
which has entered the refrigerant circuit during repairs will be
collected by the desiccant bag in the receiver/dryer.
Note
- Replace the receiver/dryer if refrigerant circuit has been
open for a long time (beyond the normal repair time) and
moisture has penetrated inside, or if required due to a specific
complaint. Refer to
→ Chapter "Refrigerant Circuit Components, Replacing".
- Only remove sealing plugs shortly before installation.
- A desiccant bag in an unsealed receiver/dryer becomes
saturated with moisture after a short period of time and
unusable.
- When installing, note arrow for direction of flow if
necessary.
- Depending on the version of the refrigerant circuit, the
receiver/dryer is also installed (integrated) either on the
condenser or inside the condenser. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual) and the Parts Catalog.
- The procedure is different for each complaint depending on
the version of the receiver/dryer and the dryer cartridge. If
the receiver/dryer, for example, is attached to the condenser,
then it can be replaced complete with the drying cartridge. If
the receiver/dryer, for example, is inside the condenser, then
the dryer cartridge, and any possible additional filters, can be
replaced separately, on most versions. If the receiver/dryer is
inside the condenser and there is absolutely no way to replace
the reservoir or the dry cartridge individually, then the entire
condenser must be replaced. Refer to
→Heating, Ventilation and Air Conditioning; Rep. Gr.87
and
→Heating, Ventilation and Air Conditioning; Rep. Gr.87
(vehicle-specific repair manual) and Parts Catalog.
- Depending on the construction of the refrigerant circuit,
the receiver can also be secured onto the condenser. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual) and the Parts Catalog.
READ NEXT:
The expansion valve atomizes the streaming refrigerant and
controls the flow quantity so that the vapor is gaseous only at
the evaporator outlet, depending on the heat transmission.
Note
B
WARNING
The quick-release coupling connectors may be
unlocked and opened only if the refrigerant circuit is
empty.
Note
This illustration shows the quick-coupling connection with
Refrigerant Circuit with Expansion Valve and Evaporator
The following illustration shows only the principle of a
refrigerant circuit, the design of the refrigerant circuit in
the respective vehicle
SEE MORE:
Special tools and workshop equipment required
Engine Support Bridge -10-222A-
Engine Sling -2024A-
Engine Support Bridge Adapter -3147-
Ring Wrench 7-Piece Set -3337-
Torque Wrench 1332 Insert - Ring Wrench - 16mm -VAG1332/14-
Shop Crane -VAS6100-
Engine Bung Set -VAS6122-
Coolant Collectio
Seat Heating Element, Removing and Installing, Seat Cushion
Procedure
- Separate the cover and cushion. Refer to
→ Chapter "Seat Pan Cover and Cushion, Separating".
- Clip the wires directly at the heating elements.
Note
The old heating elements remain on the cushion and wi