2011 INFINITI QX56 Cooling

DIAGNOSIS AND REPAIR WORKFLOWHA-17
< BASIC INSPECTION >
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>> GO TO 2.
2.SYMPTOM CHECK
Check the symptom from the customer's information. Check that any symptom occurs other than the inter-
viewed symptom.
Insufficient cooling/heating>>GO TO 3.
Refrigerant leakage>>GO TO 6.
Noise >> GO TO 7.
3.CONTROL SYSTEM DIAGNOSIS
Perform the system diagnosis for t he A/C control system. Refer to HAC-60, "
Work Flow".
Is A/C control system normal?
YES >> GO TO 4.
NO >> GO TO 8.
4.PERFORMANCE TEST
Perform the performance test. Check t he operation of each part. Refer to HA-25, "
Inspection".
>> GO TO 5.
5.TROUBLE DIAGNOSIS FOR UNUSUAL PRESSURE
Diagnose using a manifold gauge whenever system's high and/ or low side pressure(s) is/are unusual. Specify
the malfunctioning part. Refer to HA-27, "
Symptom Table".
Low refrigerant charge>>GO TO 6.
Except above>>GO TO 8.
6.CHECK REFRIGERANT FOR LEAKAGES
Check refrigerant for leakages. Specify the malfunctioning part. Refer to HA-18, "
Leak Test".
>> GO TO 8.
7.TROUBLE DIAGNOSIS FOR NOISE
Perform trouble diagnosis for noise. Specify the malfunctioning part. Refer to HA-29, "
Symptom Table".
>> GO TO 8.
8.MALFUNCTION PART REPAIR
Repair or replace the malfunctioning part.
>> GO TO 9.
9.REPAIR CHECK (OPERATION CHECK)
Check the operation of each part.
Does it operate normally?
YES >> INSPECTION END
NO >> GO TO 2.
Revision: 2010 May2011 QX56

REFRIGERANTHA-19
< BASIC INSPECTION >
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Never look directly into UV lamp light source.
NOTE:
 For continuous operating time of UV lamp, fo llow the manufacturer operating instructions.
 Illuminate piping joints from different angles us ing UV lamp and check that there is no leakage.
 Use a mirror in area that is difficult to see to check refrigerant leakage.
 Refrigerant leakage from evaporator can be detected by soaking cotton swab or a similar material with
drain hose water and illuminating it using UV lamp.
 Dust, dirt, and packing materials adhesive used for condenser, evaporator, and other locations may flu- oresce. Be careful not to misidentify leakage.
5. Repair or replace parts where refrigerant leak age occurs and wipe off fluorescent leak detection dye.
NOTE:
Completely wipe off fluorescent leak detection dy e from gaps between parts, screw threads, and others
using a cotton swab or similar materials.
6. Use a UV lamp to check that no fluorescent leak detection dye remains after finishing work. WARNING:
Never look directly into UV lamp light source.
NOTE:
 For continuous operating time of UV lamp, fo llow the manufacturer operating instructions.
 Dust, dirt, and packing materials adhesive used for condenser, evaporator, and other locations may flu-
oresce. Be careful not to misidentify leakage.
CHECK REFRIGERANT LEAKAGE USIN G ELECTRICAL LEAK DETECTOR
WARNING:
Never check refrigerant leakage while the engine is running.
CAUTION:
Be careful of the following items so that in accurate checks or misidentifications are avoided.
 Never allow refrigerant vapor, shop chemical vapors, cigarette smoke, or others around the vehicle.
 Always check refrigerant leakage in a low air flow environment so that refrigerant may not disperse
when leakage occurs.
1. Stop the engine.
2. Connect recovery/recycling/recharging equipment or manifold gauge set to A/C service valve.
3. Check that A/C refrigerant pressure is 345 kPa (3.52 kg/cm
2, 50 psi) or more when temperature is 16 °C
(61 °F) or more. When pressure is lower than the spec ified value, recycle refrigerant completely and fill
refrigerant to the specified level.
NOTE:
Leakages may not be detected if A/C refri gerant pressure is 345 kPa (3.52 kg/cm
2, 50 psi) or less when
temperature is less than 16 °C (61 °F).
4. Clean area where refrigerant leakage check is per formed, and check refrigerant leakage along all sur-
faces of pipe connections and A/C system com ponents using electrical leak detector probe.
CAUTION:
 Continue checking when a leakage is found. Always continue and complete checking along all
pipe connections and A/C system co mponents for additional leakage.
 When a leakage is detected, clean leakage area using compressed air and check again.
 When checking leakage of cooling unit inside, al ways clean inside of drain hose so that the
probe surface may not be exposed to water or dirt.
NOTE:
 Always check leakage starting from high-pressure side and continue to low-pressure side.
 When checking leakage of cooling unit inside, operate blower fan motor for 15 minutes or more at the maximum fan speed while the engine is stopped, and then insert electrical leak detector probe into drain
hose and hold for 10 minutes or more.
 When disconnecting shut-off valve that is connected to A/C service valve, always evacuate remaining
refrigerant so that misidentification can be avoided.
5. Repair or replace parts where refrigerant leak age is detected. (Leakage is detected but leakage area is
unknown. GO TO 6.)
6. Start the engine and set A/C control in the following conditions.  A/C switch ON
 Air flow: VENT (ventilation)
 Intake door position: Recirculation
Revision: 2010 May2011 QX56

HA-22
< BASIC INSPECTION >
LUBRICANT
LUBRICANT
DescriptionINFOID:0000000006276153
MAINTENANCE OF LUBRICANT LEVEL
The compressor lubricant is circulating in the system together with the refrigerant. It is necessary to fill com-
pressor with lubricant when replacing A/C system pa rts or when a large amount of refrigerant leakage is
detected. It is important to always maintain lubricant level within the specified level. Otherwise, the following
conditions may occur.
 Insufficient lubricant amount: Stuck compressor
 Excessive lubricant amount: Insufficient cooling (caused by insufficient heat exchange)
InspectionINFOID:0000000006276154
If a compressor is malfunctioning (internal noise, insufficient cooling), check the compressor oil.
1.COMPRESSOR OIL JUDGMENT
1. Remove the compressor. Refer to HA-30, "
Exploded View".
2. Sample a compressor oil and judge on the figure.
Judgement result 1>>Replace compressor only.
Judgement result 2>>Replace compressor and liquid tank.
Perform Lubricant Return OperationINFOID:0000000006276155
CAUTION:
If a large amount of refrigerant or lubricant leakag e is detected, never perform lubricant return opera-
tion.
1. Start the engine and set to the following conditions.
 Engine speed: Idling to 1,200 rpm
 A/C switch: ON
 Fan speed: Maximum speed set
 Intake door position: Recirculation
 Temperature setting: Full cold
2. Perform lubricant return operation for approximately 10 minutes.
3. Stop the engine.
4. Lubricant return operation is complete.
Lubricant Adjusting Procedure for Comp onents Replacement Except Compressor
INFOID:0000000006276156
Fill with lubricant for the amount that is calculated according to the following conditions.
Example: Lubricant amount to be added when replacing evapor ator and liquid tank [m (Imp fl oz.)] = 35 (1.2)
+ 20 (0.7) + 5 (0.2) + α
Name A/C System Oil Type S
JSIIA0927GB
Revision: 2010 May2011 QX56

REFRIGERATION SYSTEM SYMPTOMSHA-27
< SYMPTOM DIAGNOSIS >
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SYMPTOM DIAGNOSIS
REFRIGERATION SYSTEM SYMPTOMS
Trouble Diagnosis For Unusual PressureINFOID:0000000006276159
Diagnose using a manifold gauge whenever system’s high and/or low side pressure(s) is/are unusual. The
marker above the gauge scale in the following tables i ndicates the standard (usual) pressure range. Refer to
above table (Ambient air temperature-to-operating pre ssure table) since the standard (usual) pressure, how-
ever, differs from vehicle to vehicle.
Symptom TableINFOID:0000000006276160
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too high. The pressure returns to nor-
mal soon after sprinkling wa-
ter on condenser.
Overfilled refrigerant. Collect all refrigerant, evacuate
refrigerant cycle again, and
then refill it with the specified
amount of refrigerant.
Air flow to condenser is insuf-
ficient. Insufficient condenser cooling
performance.
 Poor fan rotation of radiator
and condenser.
 Improper installation of air guide.
 Clogged or dirty condenser fins.  Repair or replace malfunc-
tioning parts.
 Clean and repair condenser fins.
When compressor is stopped,
a high-pressure reading
quickly drops by approximate-
ly 196 kPa (2 kg/cm
2, 28 psi).
It then gradually decreases. Air mixed in refrigerant cycle.
Collect all refrigerant, evacuate
refrigerant cycle again, and
then refill it with the specified
amount of refrigerant.
 Low-pressure pipe is cooler than the outlet of evapora-
tor.
 Low-pressure pipe is frost- ed. Expansion valve opened too
much (excessive flow of refrig-
erant).
Replace expansion valve.
High-pressure side is excessively
high and low-pressure side is too
low. High-pressure pipe and upper
side of condenser become
hot, however, liquid tank does
not become so hot.Clogged or crushed high-pres-
sure pipe located between
compressor and condenser.
Repair or replace the malfunc-
tioning parts.
High-pressure side is too low and
low-pressure side is too high.  The readings of both sides
become equal soon after
compressor operation
stops.
 There is no temperature dif- ference between high- and
low-pressure sides. Malfunction in compressor sys-
tem (insufficient compressor
pressure operation).
 Damage or breakage of
valve.
 Malfunctioning gaskets. Replace compressor.
AC359A
AC360A
AC356A
Revision: 2010 May2011 QX56

COMPRESSORHA-31
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Perform lubricant return operati on before each refrigeration system disassembly. However, if a large
amount of refrigerant or lubricant is detected, n ever perform lubricant return operation. Refer to HA-
22, "Perform Lubricant Return Operation".
REMOVAL
1. Use a refrigerant collecting equipment (for HF C-134a) to discharge the refrigerant. Refer to HA-20, "Recy-
cle Refrigerant".
2. Remove air cleaner. Refer to EM-27, "
Removal and Installation".
3. Remove mounting bolts, and then disconnect low-pressure flexible hose and high-pressure flexible hose from the compressor.
CAUTION:
Cap or wrap the joint of the A/C piping and comp ressor with suitable material such as vinyl tape to
avoid the entry of air.
4. Remove front under cover. Refer to EXT-25, "
Exploded View".
5. Remove drive belt. Refer to EM-20, "
Removal and Installation".
6. Remove mounting bolts (A), and harness clip, and then remove bracket (1).
7. Remove cooling fan shroud (lower). Refer to CO-16, "
Exploded View".
8. Disconnect compressor (magnet clutch) connector.
9. Remove mounting bolts, and then remove compressor form the vehicle.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Tighten compressor mounting bolts in numerical order as shown in the figure.
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 Perform lubricant adjusting procedure befo re installing new compressor. Refer to HA-23, "
Lubricant
Adjusting Procedure for Compressor Replacement".
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
 Check tension of the drive belt afte r installing compressor. Refer to EM-20, "
Checking".
MAGNET CLUTCH
MAGNET CLUTCH : Removal and Inst allation of Compressor ClutchINFOID:0000000006276164
REMOVAL
1. Fix clutch disc.
: Vehicle front
JMIIA0681ZZ
JMIIA0804ZZ
Revision: 2010 May2011 QX56

HA-34
< REMOVAL AND INSTALLATION >
COOLER PIPE AND HOSE
REAR
HIGH-PRESSURE FLEXIBLE HOSE
HIGH-PRESSURE FLEXIBLE HOSE : Removal and InstallationINFOID:0000000006276173
CAUTION:
Perform lubricant return operation before each re frigeration system disassembly. However, if a large
amount of refrigerant or lubrican t is detected, never perform lubricant return operation. Refer to HA-
22, "Perform Lubricant Return Operation".
REMOVAL
1. Use a refrigerant collecting equipment (for HF C-134a) to discharge the refrigerant. Refer to HA-20, "Recy-
cle Refrigerant".
2. Remove air cleaner. Refer to EM-27, "
Removal and Installation".
3. Remove mounting bolt, and then remove high-pressure flexible hose from the vehicle. CAUTION:
Cap or wrap the joint of the A/ C piping, condensor and compressor with suitable material such as
vinyl tape to avoid the entry of air.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
JMIIA0625GB
1. Rear A/C unit assembly 2. O-ring 3. Clamp
4. Rear cooler & heater pipe assembly 5. Rear heater bypas hose 6. Rear cooler pipe cover
7. Heater hose 8. Front water outlet tube 9. Gromet
10. Clamp 11. Cap 12. Front heater outlet hose
A. To front cooler sycle B. To front heater core C. To cooling sycle
Refer to GI-4, "
Components" for symbols in the figure.
Revision: 2010 May2011 QX56

HA-36
< REMOVAL AND INSTALLATION >
COOLER PIPE AND HOSE
9. Partly remove rear half of front fender protector RH. Refer to EXT-23, "FENDER PROTECTOR : Exploded
View".
10. Remove high-pressure pipe.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
LOW-PRESSURE PIPE
LOW-PRESSURE PIPE : Removal and InstallationINFOID:0000000006276176
CAUTION:
Perform lubricant return operation before each re frigeration system disassembly. However, if a large
amount of refrigerant or lubrican t is detected, never perform lubricant return operation. Refer to HA-
22, "Perform Lubricant Return Operation".
REMOVAL
1. Use a refrigerant collecting equipment (for HF C-134a) to discharge the refrigerant. Refer to HA-22, "Per-
form Lubricant Return Operation".
2. Drain engine coolant from cooling system. Refer to CO-8, "
Draining".
3. Remove engine cover. Refer to EM-25, "
Removal and Installation".
4. Remove mouting bolt (A) and fixing pawls, and then remove relay box (1).
5. Remove mounting bolts (A), and then remove relay box bracket(1).
6. Remove front water outlet tube assembly mounting nut.
7. Remove mounting nuts, and then disconnec t mounting bracket from the vhiecle.
8. Remove mounting bolt, and then disconnect low-pressure pipe from low-pressure flexible hose. CAUTION:
Cap or wrap the joint of the A/C piping with suitab le material such as vinyl tape to avoid the entry
of air.
9. Remove mounting bolt, and then disconnect low-pressure pipe from expansion valve. CAUTION:
: Pawl
JMIIA0798ZZ
JMIIA0799ZZ
Revision: 2010 May2011 QX56

A/C UNIT ASSEMBLYHA-41
< REMOVAL AND INSTALLATION >
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A/C UNIT ASSEMBLY
Exploded ViewINFOID:0000000006276182
REMOVAL
DISASSEMBLY
1. Heater & cooling unit assembly 2. Steering member 3. Instrument stay LH
4. Instrument stay RH 5. Blower unit assembly
Refer to GI-4, "
Components" for symbols in the figure.
JMIIA0628GB
Revision: 2010 May2011 QX56