Nissan Pathfinder (2008 year). Manual — part 427
REFRIGERATION SYSTEM
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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
INFOID:0000000001675592
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
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OIL
Maintenance of Oil Quantity in Compressor
INFOID:0000000001675593
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
< FUNCTION DIAGNOSIS >
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
INFOID:0000000001675594
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
*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
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