2007 INFINITI QX56 engine coolant

TROUBLE DIAGNOSISATC-109
< SERVICE INFORMATION >
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OK >> GO TO 6.
NG >> Check the air mix door motor circuit. Refer to ATC-59, "
Air Mix Door Motor Circuit" .
6.CHECK AIR DUCTS
Check for disconnected or leaking air ducts.
OK or NG
OK >> GO TO 7.
NG >> Repair all disconnected or leaking air ducts.
7.CHECK HEATER HOSE TEMPERATURES
1. Start engine and warm it up to normal operating temperature.
2. Touch both the inlet and outlet heater hoses.
OK or NG
OK >> Hot inlet hose and a warm outlet hose: GO TO 8.
NG >> • Inlet hose cold: GO TO 11. • Both hoses warm: GO TO 9.
8.CHECK ENGINE COOLANT SYSTEM
Check engine control temperature sensor. Refer to EC-205
.
OK or NG
OK >> System OK.
NG >> Repair or replace as necessary. Retest.
9.CHECK HEATER HOSES
Check heater hoses for proper installation.
OK or NG
OK >> System OK.
NG >> 1. Back flush heater core. 2. Drain the water from the system.
3. Refill system with new engine coolant. Refer to CO-9, "
Changing Engine Coolant" .
4. GO TO 10 to retest.
10.CHECK HEATER HOSE TEMPERATURES
1. Start engine and warm it up to normal operating temperature.
2. Touch both the inlet and outlet heater hoses.
OK or NG
OK >> System OK.
NG >> Replace heater core. Refer to ATC-135
.
11 .CHECK WATER VALVE
Check the operation of the water valve. Refer to ATC-113, "
Water Valve Circuit".
OK or NG
OK >> System OK.
NG >> Replace water valve.
NoiseINFOID:0000000003533262
SYMPTOM: Noise
INSPECTION FLOW

TROUBLE DIAGNOSISATC-113
< SERVICE INFORMATION >
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Does another symptom exist?
YES >> Refer to ATC-32, "How to Perform Trouble Diagnosis for Quick and Accurate Repair".
NO >> Replace front air control. Refer to ATC-123, "
Removal and Installation".
Water Valve CircuitINFOID:0000000003533265
COMPONENT DESCRIPTION
Water Valve
The water valve (1) cuts the flow of engine coolant to the front and
rear heater cores to allow for maximum cooling during A/C opera-
tion. It is controlled by the front air control.
DIAGNOSTIC PROCEDURE FOR WATER VALVE
1.CHECK WATER VALVE POWER AND GROUND CIRCUITS
1. Disconnect water valve connector F68.
2. Turn ignition switch ON.
3. Rotate temperature control dial (driver) to 32 °C (90 °F).
4. Check voltage between water valve harness connector F68 ter- minal 1 and terminal 2 while rotating temperature control dial
(driver) to 16 °C (60 °F).
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2.CHECK WATER VALVE CONTROL OUTPUT CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front air control connector M50.
3. Check continuity between water valve harness connector F68 (A) terminal 1 and front air control harness connector M50 (B)
terminal 29.
4. Check continuity between water valve harness connector F68 (A) terminal 1 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-123, "Removal and Installation".
WJIA1791E
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Water valve: F68 1 2 Rotate temperature
control dial Battery
voltage
WJIA1792E
1 - 29 : Continuity should exist.
1 - Ground : Continuity should not exist.
WJIA1793E

HEATER & COOLING UNIT ASSEMBLYATC-133
< SERVICE INFORMATION >
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Rear Heater and Cooling Unit Assembly
Removal and InstallationINFOID:0000000003533279
FRONT HEATER AND COOLING UNIT ASSEMBLY
Removal
1. Move the two front seats to the rearmost position on the seat track.
2. Disconnect the battery negative terminal and battery positive terminal.
3. Discharge the refrigerant from the A/C system. Refer to ATC-150, "
HFC-134a (R-134a) Service Proce-
dure".
4. Drain the coolant from the engine cooling system. Refer to MA-12, "
Changing Engine Coolant".
WJIA2315E
1. Rear heater and cooling unit assembly 2. Rear A/C pipes 3. Rear A/C heater core pipes
4. Rear heater core hose 5. Rear blower motor 6. Underfloor rear A/C pipes
7. Underfloor rear heater core pipes A. Bolt torque specifications B. Leak checking order (l - r)
C. Tightening torque D. Wrench size E. O-ring size
⇐Front
NOTE: The O-ring size 8 is the high-side and the O-ring size 16 is the low-side.

ATC-134
< SERVICE INFORMATION >
HEATER & COOLING UNIT ASSEMBLY
5. Disconnect the front heater hoses from the front heater core.
6. Disconnect the high/low pressure pipes from the front expansion valve.
7. Remove the instrument panel and console panel. Refer to IP-10, "
Removal and Installation".
8. Remove the steering column. Refer to PS-10
.
9. Disconnect the instrument panel wire harness at the RH and LH in-line connector brackets, and the fuse
block (J/B) electrical connectors. Refer to PG-3
.
10. Disconnect the steering member from each side of the vehicle body.
11. Remove the front heater and cooling unit assembly with it attached to the steering member, from the vehi-
cle.
CAUTION:
Use care not to damage the seats and interior tr im panels when removing the front heater and
cooling unit assembly with it at tached to the steering member.
12. Remove the front heater and cooling unit assembly from the steering member.
Installation
Installation is in the reverse order of removal.
CAUTION:
• Replace the O-ring of the low-pressure pipe and high-pressure pipe with a new one, and apply com-
pressor oil to it when installing it.
• After charging the refrigerant, check for leaks.
NOTE:
• Fill the engine cooling system with the s pecified coolant mixture. Refer to MA-12, "
Changing Engine Cool-
ant".
• Recharge the A/C system. Refer to ATC-150, "
HFC-134a (R-134a) Service Procedure".
REAR HEATER AND COOLING UNIT ASSEMBLY
Removal
1. Discharge the refrigerant from the A/C system. Refer to ATC-150, "HFC-134a (R-134a) Service Proce-
dure".
2. Drain the coolant from the engine cooling system. Refer to MA-12, "
Changing Engine Coolant".
3. Disconnect the rear heater core hoses from the rear heater core.
4. Disconnect the rear A/C pipes from the rear expansion valve.
5. Remove the luggage side finisher lower RH. Refer to EI-34
.
6. Disconnect the following electrical connectors: • Rear blower motor
• Rear blower motor resistor
• Rear air mix door motor
7. Disconnect the ducts from the rear heater and cooling unit assembly.
8. Remove the rear heater and cooling unit assembly.
Installation
Installation is in the reverse order of removal.
CAUTION:
• Replace the O-ring of the low-pressure pipe and high-pressure pipe with a new one, and apply com-
pressor oil to it when installing it.
• After charging the refrigerant, check for leaks.
NOTE:
• Fill the engine cooling system with the s pecified coolant mixture. Refer to MA-12, "
Changing Engine Cool-
ant".
• Recharge the A/C system. Refer to ATC-150, "
HFC-134a (R-134a) Service Procedure".
LJIA0021E

HEATER COREATC-137
< SERVICE INFORMATION >
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5. Remove the heater core. NOTE:
If the in-cabin microfilters are c ontaminated from coolant leaking
from the heater core, replace the in-cabin microfilters with new
ones before installing the new heater core.
Installation
Installation is in the reverse order of removal.
REAR HEATER CORE
Removal
1. Partially drain the engine cooling system. Refer to MA-12, "Changing Engine Coolant".
2. Remove the luggage side finisher lower RH. Refer to EI-39
.
3. Disconnect the rear heater hoses from the heater core.
4. Remove the rear heater core bracket.
5. Remove the heater core.
Installation
Installation is in the reverse order of removal.
LJIA0134E
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REFRIGERANT LINESATC-159
< SERVICE INFORMATION >
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Refer to ATC-152, "Component".
CAUTION:
• Replace the O-ring of the high-pressure pipe with a new one, then apply compressor oil to it when
installing it.
• After charging refrigerant, check for leaks.
Removal and Installation for Low-Pressure PipeINFOID:0000000003533298
REMOVAL
1. Discharge the refrigerant. Refer to ATC-150, "HFC-134a (R-134a) Service Procedure".
2. Remove the cowl top and the cowl top extension. Refer to EI-17
.
3. Remove the low-pressure pipe. CAUTION:
Cap or wrap the joint of the pipes with suitable material such as viny l tape to avoid the entry of air.
INSTALLATION
Installation is in the reverse order of removal.
Refer to ATC-152, "
Component".
CAUTION:
• Replace the O-ring of the high/low-pressure pipe with a new one, then apply compressor oil to it
when installing it.
• After charging refrigerant, check for leaks.
Removal and Installation for Rear High- and Low-Pressure A/C and Heater Core Pipes
INFOID:0000000003533299
REMOVAL
1. Discharge the refrigerant. Refer to ATC-150, "HFC-134a (R-134a) Service Procedure".
2. Drain the coolant from the engine cooling system. Refer to CO-9, "
Changing Engine Coolant".
3. Disconnect the underfloor rear heater hoses (1 and 2) from the rear heater pipes underneath the vehicle.
•⇐ : Front
4. Remove the rear high- and low-pressure pipes bolt (A) to dis- connect the rear high- and low-pressure pipes from the under-
floor rear high- and low-pressu re pipes underneath the vehicle.
CAUTION:
Cap or wrap the joint of the pipes with suitable material
such as vinyl tape to avo id the entry of air.
5. Remove the rear high- and low-pressure pipes nuts (B) under- neath the vehicle.
NOTE:
The remaining steps are performed inside the rear luggage area of the vehicle.
6. Remove the luggage side finisher lower RH. Refer to EI-39
.
7. Disconnect the rear heater core hoses (1 and 2) from the rear heater core (3).
•⇐ : Front
WJIA2310E
WJIA2311E

ATC-160
< SERVICE INFORMATION >
REFRIGERANT LINES
8. Remove the rear high- and low-pressure pipes bracket bolt (A)to release the bracket.
• Rear blower motor (1)
•⇐ : Front
9. Remove the rear high- and low-pressure pipes bolt (A) to dis- connect the rear high- and low-pressure pipes from the rear
expansion valve (1).
•⇐ : Front
CAUTION:
Cap or wrap the joint of the pipes with suitable material
such as vinyl tape to avoid the entry of air.
10. Disconnect the following electrical connectors: • Rear air mix door motor (1)
• Rear blower motor resistor (2)
• Rear blower motor (3)
•⇐ : Front
11. Disconnect the ducts from the rear heater and cooling unit assembly. Refer to ATC-145, "
Component".
12. Remove the rear heater and cooling unit assembly. CAUTION:
Cap or wrap the joint of the pipes with suitable material such as viny l tape to avoid the entry of air.
13. Remove the rear high- and low-pressure A/C pipes.
INSTALLATION
Installation is in the reverse order of removal.
Refer to ATC-152, "
Component".
CAUTION:
• Replace the O-ring of th e high/low-pressure pipe with a new one, then apply compressor oil to it
when installing it.
• After charging refrigerant, check for leaks.
Removal and Installati on for Underfloor Rear High- and Low-Pressure A/C and Heater
Core Pipes
INFOID:0000000003533300
REMOVAL
1. Drain the coolant from the engine cooling system. Refer to CO-9, "Changing Engine Coolant".
2. Disconnect the battery negative terminal.
3. Disconnect the generator harness.
4. Discharge the refrigerant. Refer to ATC-150, "
HFC-134a (R-134a) Service Procedure".
WJIA2312E
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CO-1
ENGINE
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CONTENTS
ENGINE COOLING SYSTEM
SERVICE INFORMATION ............................2
PRECAUTIONS ...................................................2
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ...................................................................
2
Precaution for Liquid Gasket .....................................2
PREPARATION ...................................................4
Special Service Tool .................................................4
Commercial Service Tool ..........................................4
OVERHEATING CAUSE ANALYSIS ..................6
Troubleshooting Chart ...............................................6
COOLING SYSTEM ............................................8
Cooling Circuit ...........................................................8
Schematic .................................................................8
ENGINE COOLANT ............................................9
Inspection ..................................................................9
Changing Engine Coolant .........................................9
RADIATOR ........................................................13
Removal and Installation .........................................13
Checking Radiator ...................................................15
ENGINE COOLING FAN ...................................16
Removal and Installation (Crankshaft Driven
Type) .......................................................................
16
Removal and Installation (Motor Driven Type) ........17
WATER PUMP ..................................................18
Removal and Installation .........................................18
THERMOSTAT AND WATER PIPING ..............20
Removal and Installation .........................................20
SERVICE DATA AND SPECIFICATIONS
(SDS) .................................................................
22
Standard and Limit ..................................................22