Mercedes-Benz Sprinter / Dodge Sprinter. Service manual - part 518

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) Remove the HVAC housing (Refer to 24 -

HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - REMOVAL).

(2) Disassemble the HVAC housing to access the

A/C evaporator (Refer to 24 - HEATING & AIR CON-
DITIONING/DISTRIBUTION/HVAC

HOUSING

DISASSEMBLY).

(3) Lift the A/C evaporator out of the lower half of

the HVAC housing (Fig. 9).

INSTALLATION

NOTE: If the A/C evaporator is being replaced, add
60 milliliters (2 fluid ounces) of refrigerant oil to the
refrigerant system. Use only refrigerant oil of the

type recommended for the A/C compressor in the
vehicle.

(1) Install the A/C evaporator into the lower half of

the HVAC housing.

(2) Assemble the HVAC housing (Refer to 24 -

HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - ASSEMBLY).

(3) Install the HVAC housing (Refer to 24 - HEAT-

ING & AIR CONDITIONING/DISTRIBUTION/HVAC
HOUSING - INSTALLATION).

A / C EXPANSION VALVE

DESCRIPTION

The A/C expansion valve controls the amount of

refrigerant entering the A/C evaporator and is of a
thermostatic expansion valve (TXV) design (Fig. 10).
The A/C expansion valve consists of an aluminum
H-valve type body with an integral thermal sensor.

The A/C expansion valve is located at the dash

panel between the A/C refrigerant lines and the A/C
evaporator.

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
A/C expansion valve monitors the temperature of the
refrigerant leaving the A/C evaporator and adjusts
the orifice size at the evaporator inlet to allow the
proper amount of refrigerant into the A/C evaporator

Fig. 9 HVAC Housing

1 - SCREW (12)
2 - UPPER HOUSING
3 - A/C EVAPORATOR
4 - EVAPORATOR O-RING SEAL (2)
5 - EVAPORATOR GASKET
6 - VENTILATION HOUSING GASKET
7 - LOWER HOUSING
8 - WIRING HARNESS
9 - BOLT (3)
10 - HEATER CORE
11 - HEATER CORE TUBE ASSEMBLY
12 - HEATER CORE TUBE GASKET
13 - HEATER CORE TUBE O-RING SEAL (2)

Fig. 10 Front A/C Expansion Valve

1 - A/C EXPANSION VALVE
2 - THERMAL SENSOR

PLUMBING

24 - 73

in order to meet vehicle cooling requirements. Con-
trolling the refrigerant flow through the A/C evapo-
rator ensures that none of the refrigerant leaving the
evaporator is still in a liquid state, which could cause
damage to the A/C compressor.

The A/C expansion valve is factory calibrated and

cannot be adjusted or repaired and, if faulty or dam-
aged, it must be replaced.

DIAGNOSIS AND TESTING

A / C EXPANSION VALVE

The A/C expansion valve is located on the engine

side of the dash panel near the shock tower.

The A/C expansion valve can fail in three different

positions (open, closed or restricted).

In an Open Position: this will result in a noisy A/C

compressor or no cooling. The cause can be broken
spring, broken ball or excessive moisture in the A/C
system. If the spring or ball are found to be defective,
replace the A/C expansion valve. If excessive mois-
ture is found in the A/C system, recycle the refriger-
ant.

In a Closed Position: There will be low suction

pressure and no cooling. This may be caused by a
failed power dome or excessive moisture in the A/C
system. If the power dome on the A/C expansion
valve is found to be defective replace the A/C expan-
sion valve. If excessive moisture is found recycle the
refrigerant.

A Restricted Orifice: There will be low suction

pressure and no cooling. This may be caused by
debris in the refrigerant system. If debris is believed
to be the cause, recycle the refrigerant and replace
the A/C expansion valve and the receiver-drier.

REMOVAL

(1) Recover the refrigerant from the A/C system

(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE - REFRIG-
ERANT SYSTEM RECOVERY).

(2) Disconnect and isolate the negative battery

cable.

(3) Remove the nut that secures the suction and

liquid line fittings to the stud on the A/C expansion
valve (Fig. 11).

(4) Disconnect the suction and liquid lines from

the expansion valve.

(5) Remove the seals from the suction and liquid

line fitting and discard.

(6) Install plugs in, or tape over the opened liquid

and suction line fittings and both expansion valve
ports.

(7) Remove the two bolts that secure the expan-

sion valve to the evaporator tube tapping plate.

(8) Remove the expansion valve from the evapora-

tor tube tapping plate.

(9) Remove the seals from the evaporator inlet and

outlet tube fittings and discard.

(10) Install plugs in, or tape over the opened evap-

orator inlet and outlet tube fittings and both expan-
sion valve ports.

INSTALLATION

(1) Remove the tape or plugs from the tapping

plate evaporator inlet and outlet tube fittings and
both ports on the back of the A/C expansion valve.

(2) Lubricate new rubber O-ring seals with clean

refrigerant oil and install them on the tapping plate
evaporator inlet and outlet tube fittings.

(3) Position the A/C expansion valve onto the tap-

ping plate evaporator inlet and outlet tube fittings.

Fig. 11 A/C Expansion Valve

1 - EVAPORATOR TUBE TAPPING PLATE
2 - O-RING SEAL (2)
3 - A/C EXPANSION VALVE
4 - BOLT (2)
5 - A/C SUCTION LINE
6 - NUT
7 - A/C LIQUID LINE
8 - O-RING SEAL (2)

24 - 74

PLUMBING

(4) Install the two bolts that secure the A/C expan-

sion valve to the evaporator tube tapping plate.
Tighten the bolts to 5 N·m (45 in. lbs.).

(5) Remove the tape or plugs from the liquid and

suction line fittings and both expansion valve ports.

(6) Lubricate new rubber O-ring seals with clean

refrigerant oil and install them on the liquid and suc-
tion line fittings.

(7) Connect the liquid line fitting to the A/C expan-

sion valve.

(8) Connect the suction line fitting to the A/C

expansion valve.

(9) Install the nut that secures the suction line

and liquid line fittings to the stud on the A/C expan-
sion valve. Tighten the nut to 10 N·m (89 in. lbs.).

(10) Reconnect the negative battery cable.
(11) Evacuate the refrigerant system (Refer to 24 -

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

(12) Charge the refrigerant system (Refer to 24 -

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

ELECTRIC COOLANT PUMP

DESCRIPTION

The electric coolant pump ensures the uniform flow

of coolant through the heater core without bubbles,
even at low speeds (Fig. 12). The electric coolant
pump is located in the left side of the engine com-
partment near the battery and is controlled by the
A/C-heater control.

The electric coolant pump housing contains two

coolant hose connections and an electric motor which
drives

the

vane-type

pump

using

magnetic

clutch.

OPERATION

The electric coolant pump is controlled by the ATC

A/C-heater control and is only operational when the
ignition switch is on under the following conditions:

(1) Vehicle speed below 27 Km/h (17 mph).
(2) Coolant temperature above 65° C (150° F) but

less than 110° C (230 ° F).

(3) Any blower motor speed setting.
(4) Temperature heat setting above the halfway

setting (60% heat).

(5) The pump will turn off at speeds above 48

Km/h (30 mph).

(6) The pump will turn off if the coolant tempera-

ture rises above 110° C (230 ° F).

REMOVAL

(1) Disconnect and isolate the negative battery

cable.

(2) Partially

drain

the

engine

cooling

system

(Refer to 7 - COOLING/ENGINE/COOLANT - STAN-
DARD PROCEDURE - DRAINING COOLANT SYS-
TEM).

(3) Disconnect the wire harness connector from the

electric coolant pump (Fig. 13).

(4) Loosen both hose clamps from the electric cool-

ant pump.

(5) Using a twisting motion gently remove both

heater hoses from the electric coolant pump.

(6) Remove the two electric coolant pump bracket

retaining nuts from the body studs.

(7) Remove the electric coolant pump from the

vehicle.

Fig. 12 Electric Coolant Pump

1 - ELECTRIC COOLANT PUMP
2 - COOLANT HOSE CONNECTIONS
3 - WIRE CONNECTOR

PLUMBING

24 - 75

INSTALLATION

(1) Install the electric coolant pump and mounting

bracket onto the body studs.

(2) Install the two bracket retaining nuts. Tighten

the nuts to 5 N·m (45 in. lbs.).

(3) Using a twisting motion gently install both

hoses onto the electric coolant pump.

(4) Tighten both hose clamps securely.
(5) Connect the wire harness connector to the elec-

tric coolant pump.

(6) Reconnect the negative battery cable.
(7) Fill the engine cooling system (Refer to 7 -

COOLING/ENGINE/COOLANT - STANDARD PRO-
CEDURE - COOLING SYSTEM FILL).

HEATER CORE

DESCRIPTION

The heater core is mounted into the HVAC hous-

ing, located behind the instrument panel (Fig. 14).
The heater core is a heat exchanger made of rows of
tubes and fins. The heater core tubes are attached to
the heater core by using O-ring seals and bolts.

The heater core is serviced by removing and disas-

sembling the HVAC housing.

OPERATION

Engine coolant is circulated through the heater

hoses to the heater core whenever the heater water
valve is cycled open by the ATC A/C-heater control.
As the coolant flows through the heater core, heat
removed from the engine is transferred to the heater
core fins and tubes. Air directed through the heater
core picks up the heat from the heater core fins. The
heater water valve controls the heater output air
temperature by controlling the amount of heated
engine coolant flowing through the heater core. The
blower motor speed controls the volume of air flowing
through the HVAC housing.

The heater core cannot be repaired and, if faulty or

damaged, it must be replaced.

REMOVAL

WARNING: To avoid personal injury or death, on
vehicles equipped with airbags, disable the supple-
mental

restraint

system

before

attempting

any

steering wheel, steering column, airbag, seat belt
tensioner, impact sensor, or instrument panel com-
ponent diagnosis or service. Disconnect and isolate
the battery negative (ground) cable, then wait two
minutes for the system capacitor to discharge
before performing further diagnosis or service. This
is the only sure way to disable the supplemental
restraint system. Failure to take the proper precau-
tions could result in accidental airbag deployment.

Fig. 13 Electric Coolant Pump

1 - HEATER HOSE
2 - HOSE CLAMP (2)
3 - HEATER HOSE
4 - ELECTRIC COOLANT PUMP
5 - WIRE HARNESS CONNECTOR
6 - NUT (2)

Fig. 14 Front Heater Core

1 - HEATER CORE
2 - BOLT (3)
3 - HEATER CORE TUBES
4 - O-RING SEALS

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PLUMBING

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