Nissan Pathfinder (2008 year). Manual - part 427

REFRIGERATION SYSTEM

HA-19

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Front A/C Compressor and Condenser - VQ40DE

REAR REFRIGERATION SYSTEM

WJIA1399E

1.

High-pressure service valve

2.

Clip

3.

Front high-pressure A/C pipe

4.

Refrigerant pressure sensor

5.

Condenser

6.

Compressor shaft seal

7.

Front high-pressure flexible A/C hose

8.

Front low-pressure flexible A/C hose

9.

Low-pressure service valve

10. Front low-pressure A/C pipe

11.

Front expansion valve

12. Front A/C drain hose

HA-20

< FUNCTION DIAGNOSIS >

REFRIGERATION SYSTEM

Rear A/C

WJIA1400E

1.

Rear high- and low-pressure A/C pipes

2.

Rear heater core hoses

3.

Underfloor rear high- and low-pres-
sure A/C and heater core pipes

4.

Rear expansion valve

REFRIGERATION SYSTEM

HA-21

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Refrigerant Cycle

INFOID:0000000001675591

REFRIGERANT FLOW

The refrigerant flows in the standard pattern, that is, through the compressor, the condenser with liquid tank,
through the front and rear evaporators, and back to the compressor. The refrigerant evaporation through the
evaporator coils are controlled by front and rear externally equalized expansion valves, located inside the front
and rear evaporator cases.

FREEZE PROTECTION

The compressor cycles on and off to maintain the evaporator temperature within a specified range. When the
evaporator coil temperature falls below a specified point, the intake sensor interrupts the compressor opera-
tion. When the evaporator coil temperature rises above the specification, the intake sensor allows compressor
operation.

Refrigerant System Protection

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REFRIGERANT PRESSURE SENSOR

The refrigerant system is protected against excessively high- or low-pressures by the refrigerant pressure sen-
sor, located on the condenser. If the system pressure rises above or falls below the specifications, the refriger-
ant pressure sensor detects the pressure inside the refrigerant line and sends a voltage signal to the ECM.

WJIA1342E

HA-22

< FUNCTION DIAGNOSIS >

REFRIGERATION SYSTEM

The ECM de-energizes the A/C relay to disengage the magnetic compressor clutch when pressure on the high
pressure side detected by refrigerant pressure sensor is over about 2,746 kPa (28 kg/cm

2

, 398 psi), or below

about 120 kPa (1.22 kg/cm

2

, 17.4 psi).

PRESSURE RELIEF VALVE

The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor.
When the pressure of refrigerant in the system increases to an abnormal level [more than 2,990 kPa (30.5 kg/
cm

2

, 433.6 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into

the atmosphere.

OIL

HA-23

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OIL

Maintenance of Oil Quantity in Compressor

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The oil in the compressor circulates through the system with the refrigerant. Add oil to compressor when
replacing any component or after a large refrigerant leakage has occurred. It is important to maintain the spec-
ified amount.
If oil quantity is not maintained properly, the following malfunctions may result:
• Lack of oil: May lead to a seized compressor
• Excessive oil: Inadequate cooling (thermal exchange interference)

OIL

Oil name: NISSAN A/C System Oil Type S or equivalent

CHECKING AND ADJUSTING

CAUTION:

If excessive oil leakage is noted, do not perform the oil return operation.
Start the engine and set the following conditions:

Test Conditions

• Engine speed: idling to 1,200 rpm
• A/C switch: ON
• Blower fan speed: HIGH
• Temperature control: optional [set so intake air temperature is 25

°

 to 30

°

 C (77

°

 to 86

°

F)]

• Intake position: RECIRCULATION mode
• Perform oil return operation for about ten minutes
Adjust the oil quantity according to the following table.

Oil Adjusting Procedure for Components Replacement Except Compressor

After replacing any of the following major components, add the correct amount of oil to the system.

Amount of Oil to be Added

*1:

If refrigerant leak is small, no addition of oil is needed.

Oil Adjustment Procedure for Compressor Replacement

Part replaced

Oil to be added to system

Remarks

Amount of oil

m

 (US fl oz, Imp fl oz)

Front evaporator

75 (2.5, 2.6)

—

Rear evaporator

75 (2.5, 2.6)

—

Condenser

75 (2.5, 2.6)

—

Liquid tank

5 (0.2, 0.2)

Add if compressor is not replaced.

In case of refrigerant leak

30 (1.0, 1.1)

Large leak

—

Small leak *1

HA-24

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OIL

1.

Before connecting recovery/recycling equipment to vehicle, check recovery/recycling equipment gauges.
No refrigerant pressure should be displayed. If NG, recover refrigerant from equipment lines.

2.

Connect recovery/recycling equipment to vehicle. Confirm refrigerant purity in supply tank using recovery/
recycling equipment and refrigerant identifier. If NG, refer to 

HA-3, "Contaminated Refrigerant"

.

3.

Confirm refrigerant purity in vehicle A/C system using recovery/recycling equipment and refrigerant identi-
fier. If NG, refer to 

HA-3, "Contaminated Refrigerant"

.

4.

Discharge refrigerant into the refrigerant recovery/recycling equipment. Measure oil discharged into the
recovery/recycling equipment.

5.

Drain the oil from the “old” (removed) compressor into a graduated container and recover the amount of
oil drained.

6.

Drain the oil from the “new” compressor into a separate, clean container.

7.

Measure an amount of new oil installed equal to amount drained from “old” compressor. Add this oil to
“new” compressor through the suction port opening.

8.

Measure an amount of new oil equal to the amount recovered during discharging. Add this oil to “new”
compressor through the suction port opening.

9.

If the liquid tank also needs to be replaced, add an additional 5 m  (0.2 US fl oz, 0.2 Imp fl oz) of oil at this
time.
Do not add this 5 m  (0.2 US fl oz, 0.2 Imp fl oz) of oil if only replacing the compressor.

1.

New compressor

2.

Old compressor

3.

Recovery/recycling equipment

4.

Measuring cup X

5.

Measuring cup Y

6.

New oil

A.

Drain oil from the new compressor 
into clean container

B.

Record amount of oil recovered

C.

Add an additional 5 m

 (0.2 US fl oz, 

0.2 Imp fl oz) of new oil when replacing 
liquid tank

D.

Install new oil equal to recorded 
amounts in measuring cups X plus Y 

WJIA1716E

REFRIGERATION SYSTEM

HA-25

< ON-VEHICLE MAINTENANCE >

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ON-VEHICLE MAINTENANCE

REFRIGERATION SYSTEM

HFC-134a (R-134a) Service Procedure

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SETTING OF SERVICE TOOLS AND EQUIPMENT

Discharging Refrigerant

WARNING:

Avoid breathing A/C refrigerant and oil vapor or mist. Exposure may irritate eyes, nose and throat.
Remove HFC-134a (R-134a) refrigerant from the A/C system using certified service equipment meeting
requirements of SAE J2210 HFC-134a (R-134a) recycling equipment or SAE J2201 HFC-134a (R-134a)
recovery equipment. If an accidental system discharge occurs, ventilate the work area before resum-
ing service. Additional health and safety information may be obtained from the refrigerant and oil man-
ufacturers.

Evacuating System and Charging Refrigerant

1.

Shut-off valve

2.

A/C service valve

3.

Recovery/recycling equipment

WJIA1160E

WJIA1161E

HA-26

< ON-VEHICLE MAINTENANCE >

REFRIGERATION SYSTEM

1.

Shut-off valve

2.

A/C service valve

3.

Recovery/recycling equipment

4.

Refrigerant container (HFC-134a)

5.

Refrigerant weight scale (J-39699)

6.

Vacuum pump (J-39649)

7.

Manifold gauge set with hoses and 
couplers (J-39183-C)

*1

 

HA-27, "Maintenance of Oil Quantity 

in Compressor"

.

*3

HA-29, "Checking of Refrigerant 
Leaks"

.

*5

HA-3, "Contaminated Refrigerant"

.

*2

HA-29, "Checking of Refrigerant 
Leaks"

.

*4

HAC-21, "CONSULT-III Function 
(HVAC)"

.

WJIA1923E