Page 3297 of 5883
PREPARATION
HA-15
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(Kent-Moore No.)
Tool nameDescription
(J-41810-NI)
Refrigerant identifier equipment (R-
134a)For checking refrigerant purity and
system contamination
Power toolLoosening bolts and nuts
RJIA0197E
PBIC0190E
Page 3298 of 5883

HA-16
< FUNCTION DIAGNOSIS >
REFRIGERATION SYSTEM
FUNCTION DIAGNOSIS
REFRIGERATION SYSTEM
Refrigerant CycleINFOID:0000000001396439
REFRIGERANT FLOW
The refrigerant flows in the standard pattern, that is, through the compressor, the condenser with liquid tank,
through the evaporator, and back to the compressor. The refrigerant evaporation through the evaporator is
controlled by an externally equalized expansion valve, located inside the evaporator case.
FREEZE PROTECTION
Under usual operating conditions, when the A/C is switched ON, the compressor runs continuously, and the
evaporator pressure, and temperature is controlled by the compressor to prevent freeze up.
Refrigerant System ProtectionINFOID:0000000001396440
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 refrig-
erant pressure sensor detects the pressure inside the refrigerant line and sends the voltage signal to the ECM.
ECM makes the A/C relay go OFF and stops the compressor when pressure on the high-pressure side
detected by refrigerant pressure sensor is over about 2,746 kPa (27.46 bar, 28.0 kg/cm
2 , 398 psi), or below
about 134 kPa (1.34 bar, 1.4 kg/cm
2 , 20 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 unusual level [more than 3.8 MPa (38 bar,
38.76 kg/cm
2 , 551 psi)], the release port on the pressure relief valve automatically opens and releases refrig-
erant into the atmosphere.
1. Compressor 2. Pressure relief valve 3. Liquid tank
4. Refrigerant pressure sensor 5. Condenser 6. Expansion valve
AWIIA0054ZZ
Page 3299 of 5883
REFRIGERATION SYSTEM
HA-17
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7. Evaporator 8. Blower motor A. High-pressure gas
B. High-pressure liquid C. Low-pressure liquid D. Low-pressure gas
E. Suction port F. Discharge port G. Outside air
Page 3300 of 5883
HA-18
< FUNCTION DIAGNOSIS >
OIL
OIL
Maintenance of Oil Quantity in CompressorINFOID:0000000001396442
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 occurred. It is important to maintain the specified
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
MR18DE and HR16DE : NISSAN A/C System Oil Type R
K9K : NISSAN A/C System Oil Type S
Page 3301 of 5883

OIL
HA-19
< ON-VEHICLE MAINTENANCE >
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ON-VEHICLE MAINTENANCE
OIL
Maintenance of Oil Quantity in CompressorINFOID:0000000001396443
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 occurred. It is important to maintain the specified
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 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 ADJUSTING PROCEDURE FOR COMPRESSOR REPLACEMENT
MR18DE and HR16DE : NISSAN A/C System Oil Type R
K9K : NISSAN A/C System Oil Type S
Part replacedOil to be added to system
Remarks
Amount of oil
m (US fl oz, Imp fl oz)
Evaporator 35 (1.2, 1.2) -
Condenser 15 (0.5, 0.5) -
Liquid tank 5 (0.2, 0.2) -
In case of refrigerant leak30 (1.0, 1.1) Large leak
None *1
Small leak
*1
Page 3302 of 5883

HA-20
< ON-VEHICLE MAINTENANCE >
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. Discharge refrigerant into the refrigerant recovery/recycling equipment. Measure oil discharged into the
recovery/recycling equipment.
3. Drain the oil from the old (removed) compressor into a graduated container and recover the amount of oil
drained.
4. Drain the oil from the new compressor into a separate, clean container.
5. 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.
6. Measure an amount of new oil equal to the amount recovered during discharging. Add this oil to new com-
pressor through the suction port opening.
7. If the liquid tank also needs to be replaced, add another 5 m (0.2 US fl oz, 0.2 Imp fl oz.) of oil at this
time.
Add this 5 m (0.2 US fl oz, 0.2 Imp fl oz.) of oil only when 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 containerB. 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
Page 3303 of 5883

REFRIGERATION SYSTEM
HA-21
< ON-VEHICLE MAINTENANCE >
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REFRIGERATION SYSTEM
HFC-134a (R-134a) Service ProcedureINFOID:0000000001396444
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
A. Preferred (best) method
WJIA2195E
1. Shut-off valve 2. A/C service valve 3. Recovery/recycling equipment
4. Refrigerant container (HFC-134a) 5. Weight scale (J-39650) 6. Evacuating vacuum pump (J-39699)
WJIA2196E
Page 3304 of 5883
HA-22
< ON-VEHICLE MAINTENANCE >
REFRIGERATION SYSTEM
Checking of Refrigerant Leaks
INFOID:0000000001396447
Perform a visual inspection of all refrigeration parts, fittings, hoses and components for signs of A/C oil leak-
age, damage and corrosion. A/C oil leakage may indicate an area of refrigerant leakage. Allow extra inspec-
7. Manifold gauge set (J-39183) A. Preferred (best) method B. Alternative method
C. For charging
*1HA-19, "
Maintenance of Oil Quantity
in Compressor"
*2HA-22, "Checking of Refrigerant
Leaks"
*3HA-25, "Electronic Refrigerant Leak
Detector"
*4HAC-299, "Component Function
Check"
WJIA1923E