Mercedes-Benz Sprinter / Dodge Sprinter. Service manual — part 521

INSTALLATION

NOTE: Be certain to add refrigerant oil if the rear
A/C evaporator is being replaced. The refrigerant oil
must be drained from the old evaporator and mea-
sured to determine the amount of refrigerant oil to
add to the new evaporator. Use only refrigerant oil
of the type recommended for the rear A/C compres-
sor in the vehicle.

(1) If the rear A/C evaporator is being replaced,

install the correct amount and type of refrigerant oil
into the new rear A/C evaporator. Drain the old evap-
orator and measure the refrigerant oil. Fill the new
evaporator with the same amount of new refrigerant
oil that was drained out of the old evaporator.

(2) Position the rear A/C evaporator to the bottom

of the rear A/C evaporator housing and install four
new rivets.

(3) Position the three covers to the rear A/C evap-

orator and install eight new rivets.

(4) Install the left blower motor onto the rear A/C

evaporator housing (Refer to 24 - HEATING & AIR
CONDITIONING/DISTRIBUTION - REAR/BLOWER
MOTOR - INSTALLATION).

(5) Connect the rear A/C expansion valve to the

rear A/C evaporator and install new insulating tape
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/REAR

A/C

EXPANSION

VALVE

-

INSTALLATION).

(6) Position the condensate drain pan to the bot-

tom of the rear A/C evaporator and install the five
screws and washers that secure the drain pan to the
evaporator. Tighten the screws to 2.2 N·m (20 in.
lbs.).

(7) Install the rear A/C evaporator housing (Refer

to 24 - HEATING & AIR CONDITIONING/DISTRI-
BUTION/REAR A/C EVAPORATOR HOUSING -
INSTALLATION).

REAR A / C EXPANSION VALVE

DESCRIPTION

The rear A/C expansion valve controls the amount

of refrigerant entering the rear A/C evaporator (Fig.
24). The rear A/C expansion valve is of an externally-
equalized thermostatic expansion valve (TXV) design
and consists of a cast metal body with a removable
equalizer tube and an integral thermal sensor which
uses a capillary tube and sensing bulb.

The rear A/C expansion valve is located to the left

of the rear blower motors in the rear evaporator
housing.

OPERATION

High-pressure, high temperature liquid refrigerant

from the liquid line passes through the expansion
valve orifice, converting it into a low-pressure, low-
temperature mixture of liquid and gas before it
enters the A/C evaporator. A thermal sensor in the
rear A/C expansion valve monitors the temperature
of the refrigerant leaving the rear evaporator by use
of a sensing bulb positioned next to the evaporator
outlet tube. The thermal sensor adjusts the orifice
size at the evaporator inlet to allow the proper
amount of refrigerant into the rear A/C evaporator in
order to meet vehicle cooling requirements. Control-
ling the refrigerant flow through the A/C evaporator
ensures that none of the refrigerant leaving the evap-
orator is still in a liquid state, which could cause
damage to the A/C compressor.

To overcome the effect of the pressure drop within

the rear A/C evaporator, an external equalizer tube is
connected to the evaporator outlet tube and runs to
the underside if the diaphragm within the expansion
valve.

The rear A/C expansion valve is factory calibrated

and cannot be adjusted or repaired and, if faulty or
damaged, it must be replaced.

Fig. 24 Rear A/C Expansion Valve

1 - REAR A/C EXPANSION VALVE
2 - EQUALIZER TUBE
3 - CAPILLARY TUBE
4 - SENSING BULB

VA

PLUMBING

24 - 85

REMOVAL

WARNING: Refer to the applicable warnings and
cautions for this system before performing the fol-
lowing operation (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNINGS) and (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTIONS). Failure to follow the warnings and cau-
tions could result in possible personal injury or
death.

(1) Disconnect and isolate the negative battery

cable.

(2) Remove the cover from the rear A/C evaporator

housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/A/C EVAPORA-
TOR COVER-REAR - REMOVAL).

(3) Recover the refrigerant from the rear refriger-

ant system (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY).

(4) Remove the insulating tape from around the

area of the rear A/C expansion valve (Fig. 25).

(5) Disconnect the equalizer tube from the rear

evaporator outlet tube.

(6) Disconnect the rear liquid line from the rear

A/C expansion valve and remove and discard the
O-ring seal.

(7) Disconnect the rear A/C expansion valve from

the rear evaporator inlet tube and remove and dis-
card the O-ring seal.

(8) Remove the retaining clamp that secures the

sensor bulb to the evaporator outlet tube and remove
the expansion valve, capillary tube and sensor bulb
as an assembly.

(9) Install plugs into, or tape over the opened

refrigerant line and evaporator tube fittings and
expansion valve ports.

24 - 86

PLUMBING

VA

INSTALLATION

(1) Remove the tape or plugs from the rear refrig-

erant line and evaporator tube fittings and the rear
expansion valve ports.

(2) Lubricate a new O-ring seal with clean refrig-

erant oil and install it onto the rear evaporator inlet
tube fitting. Use only the specified O-ring seal as it is
made of a special material for the R-134a system.
Use only refrigerant oil of the type recommended for
the rear A/C compressor in the vehicle.

(3) Install the rear A/C expansion valve onto the

rear evaporator inlet tube. Tighten the nut to 35 N·m
(26 ft. lbs.).

(4) Lubricate a new O-ring seal with clean refrig-

erant oil and install it onto the rear liquid line fit-
ting. Use only the specified O-ring seal as it is made
of a special material for the R-134a system. Use only
refrigerant oil of the type recommended for the rear
A/C compressor in the vehicle.

(5) Connect the rear liquid line to the rear A/C

expansion valve. Tighten the nut to 35 N·m (26 ft.
lbs.).

(6) Connect the equalizer tube to the rear evapora-

tor outlet tube. Tighten the nut to 10 N·m (88 in.
lbs.).

(7) Position the rear expansion valve sensing bulb

onto the rear evaporator outlet tube and install the
retaining clamp securely.

(8) Install new insulating tape around the rear A/C

expansion valve area.

(9) Reconnect the negative battery cable.
(10) Evacuate the rear refrigerant system (Refer to

24 - HEATING & AIR CONDITIONING/PLUMBING
- STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE).

(11) Charge the rear refrigerant system (Refer to

24 - HEATING & AIR CONDITIONING/PLUMBING
- STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE).

(12) Install the cover onto the rear A/C evaporator

housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/A/C EVAPORA-
TOR COVER-REAR - INSTALLATION).

Fig. 25 Rear A/C Expansion Valve

1 - INSULATING TAPE
2 - REAR LIQUID LINE
3 - REAR A/C EXPANSION VALVE
4 - REAR A/C EVAPORATOR INLET TUBE

5 - RETAINING CLAMP
6 - SENSING BULB AND CAPILLARY TUBE
7 - EQUALIZER TUBE
8 - REAR A/C EVAPORATOR OUTLET TUBE

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PLUMBING

24 - 87

REAR DISCHARGE LINE

DESCRIPTION

The rear A/C discharge line is the refrigerant line

that carries refrigerant from the underbody discharge
line to the rear A/C condenser (Fig. 26). The rear A/C
discharge line is retained to the right quarter panel
by two plastic retaining clips.

CAUTION: Use only seals specified for the vehicle.
Failure to use the correct seals will cause the refrig-
erant system connections to leak.

The rear A/C discharge line has no serviceable

parts except for the O-ring seals. The O-ring seals
used on the connections are made from a special type
of rubber not affected by R-134a refrigerant and
must be replaced whenever the rear discharge line is
removed and installed.

If the rear A/C discharge line is found to be leaking

or damaged, it must be replaced.

REMOVAL

WARNING: Refer to the applicable warnings and
cautions for this system before performing the fol-
lowing operation (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNINGS) and (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTIONS). Failure to follow the warnings and cau-
tions could result in possible personal injury or
death.

(1) Disconnect and isolate the negative battery

cable.

(2) Remove the cover from the rear A/C evaporator

housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/A/C EVAPORA-
TOR COVER-REAR - REMOVAL).

(3) Recover the refrigerant from the rear refriger-

ant system (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY).

(4) Remove the cover from the rear A/C condenser

housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION

-

REAR/A/C

CON-

DENSER COVER - REMOVAL).

(5) Remove the screw and bracket that secures the

rear A/C discharge line to the right side of the rear
A/C condenser housing (Fig. 27).

(6) Disconnect the rear A/C discharge line from the

rear A/C condenser and remove and discard the
O-ring seal.

(7) Disengage the discharge line grommet from the

roof panel and push the grommet down into the
cargo compartment.

(8) Remove the right quarter trim panel (Refer to

23 - BODY/INTERIOR/QUARTER TRIM PANEL -
REMOVAL).

(9) Remove the retaining strap that secures the

rear A/C wire harness to the rear A/C discharge line
at the ceiling and position the wire harness out of
the way (Fig. 28).

Fig. 26 Rear A/C Discharge Line

1 - REAR A/C DISCHARGE LINE
2 - RETAINING CLIPS
3 - TO REAR A/C CONDENSER
4 - RIGHT INNER QUARTER PANEL
5 - TO UNDERBODY DISCHARGE LINE

Fig. 27 Rear A/C Discharge Line to Rear Condenser

1 - REAR A/C CONDENSER
2 - GROMMET
3 - REAR A/C DISCHARGE LINE
4 - CONDENSER INLET TUBE
5 - SCREW AND BRACKET

24 - 88

PLUMBING

VA