Nissan Frontier D40. Manual - part 718

REFRIGERATION SYSTEM

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< FUNCTION DIAGNOSIS >

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FUNCTION DIAGNOSIS

REFRIGERATION SYSTEM

Refrigerant Cycle

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REFRIGERANT FLOW

The refrigerant flows in the standard pattern. Refrigerant flows through the compressor, condenser, liquid tank,
expansion valve, evaporator, and back to the compressor. The refrigerant evaporation through the evaporator
coil is controlled by an externally equalized expansion valve, located inside the evaporator case.

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.
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.

WJIA1482E

HA-16

< ON-VEHICLE MAINTENANCE >

REFRIGERATION SYSTEM

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

REFRIGERATION SYSTEM

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< ON-VEHICLE MAINTENANCE >

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1.

Shut-off valve

2.

A/C service valve

3.

Recovery/Recycling equipment

4.

Refrigerant container (HFC-134a)

5.

Refrigerant weight scale

6.

Vacuum pump

7.

Manifold gauge set with hoses and 
couplers

*1

HA-16, "HFC-134a (R-134a) Service 
Procedure"

*3

HA-20, "Checking of Refrigerant 
Leaks"

*5

HA-4, "Contaminated Refrigerant"

*2

HA-20, "Checking of Refrigerant 
Leaks"

*4

HAC-6, "Operational Check"

WJIA1923E

HA-18

< ON-VEHICLE MAINTENANCE >

OIL

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

Name: NISSAN A/C System Oil Type R 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 Condition

• Engine speed: Idling to 1,200 rpm
• A/C switch: On
• Blower fan speed: Max. position
• Temp. control: Optional [Set so that intake air temperature is 25

°

 to 30

°

 C (77

°

 to 86

°

F)]

• Intake position: Recirculation (

)

• 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)

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