2011 INFINITI QX56 radiator

CO-6
< SYMPTOM DIAGNOSIS >
OVERHEATING CAUSE ANALYSIS
SYMPTOM DIAGNOSIS
OVERHEATING CAUSE ANALYSIS
Troubleshooting ChartINFOID:0000000006289656
Symptom Check items
Cooling sys-
tem parts
malfunction Poor heat transfer
Water pump malfunction Worn or loose drive belt
—
Thermostat stuck closed —
Damaged fins
Dust contamination or pa-
per clogging
Physical damage
Clogged radiator cooling
tube Excess foreign material
(rust, dirt, sand, etc.)
Reduced air flow Cooling fan does not oper-
ate
Fan assembly —
High resistance to fan rota-
tion
Damaged fan blades
Damaged radiator shroud — — —
Improper engine coolant
mixture ratio ———
Poor engine coolant quality — Engine coolant density —
Insufficient engine coolant Engine coolant leakageCooling hose
Loose clamp
Cracked hose
Water pump Poor sealing
Radiator cap Loose
Poor sealing
Radiator O-ring for da
mage, deterio-
ration or improper fitting
Cracked radiator tank
Cracked radiator core
Reservoir tank Cracked reservoir tank
Overflowing reservoir tank Exhaust gas leakage into
cooling system Cylinder head deterioration
Cylinder head gasket deteri-
oration
Revision: 2010 May2011 QX56

OVERHEATING CAUSE ANALYSISCO-7
< SYMPTOM DIAGNOSIS >
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Except cool-
ing system
parts mal-
function — Overload on engine
Abusive driving
High engine rpm under no
load
Driving in low gear for ex-
tended time
Driving at extremely high
speed
Powertrain system malfunc-
tion
—
Installed improper size
wheels and tires
Dragging brakes
Improper ignition timing
Blocked or restricted air
flow Blocked bumper —
—
Blocked radiator grille
Installed car brassiere
Mud contamination or paper
clogging
Blocked radiator —
Blocked condenser Blocked air flow
Installed large fog lamp
Symptom Check items
Revision: 2010 May2011 QX56

CO-8
< PERIODIC MAINTENANCE >
ENGINE COOLANT
PERIODIC MAINTENANCE
ENGINE COOLANT
InspectionINFOID:0000000006289657
LEVEL
 Check if the reservoir tank engine coolant level is within the “MIN”to “MAX” when the engine is cool.
 Adjust the engine coolant level if necessary. WARNING:
Never remove reservoir tank cap when engine is hot.
LEAKAGE
 To check for leakage, apply pressure to the cooling system with theradiator cap tester and radiator cap tester adapter (commercial
service tool) (A).
WARNING:
Never remove radiator cap and reservoir tank cap when
engine is hot. Serious burns could occur from high-pressure
engine coolant escaping from water inlet.
CAUTION:
Higher test pressure than specified may cause radiator dam-
age.
NOTE:
In a case that engine coolant decreas es, fill radiator with engine coolant.
 If anything is found, repair or replace damaged parts.
DrainingINFOID:0000000006289658
WARNING:
 Never remove radiator cap and reservoir tank cap when engine is hot. Serious burns could occur
from high-pressure engine co olant escaping from radiator.
 Wrap a thick cloth around the caps. Slowly turn them a quarter of a turn to release built-up pressure.
Carefully remove the caps by turning it all the way.
1. Open radiator drain plug (1) at the bottom of radiator, and then remove radiator cap and reservoir tank cap.
When draining all of engine cool ant in the system, open water drai n plug on cylinder block. Refer
to EM-103, "
Setting".
2. Remove reservoir tank if necessary, and drain engine coolant and clean reservoir tank before installing.
A: MAX
B: MIN
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Testing pressure : Refer to CO-23, "Radiator".
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2 : Front under cover
: Vehicle front
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Revision: 2010 May2011 QX56

ENGINE COOLANTCO-9
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3. Check drained engine coolant for contaminants such as rust, corrosion or discoloration.
If contaminated, flush the engine cooling system. Refer to CO-10, "
Flushing".
RefillingINFOID:0000000006289659
1. Install reservoir tank if removed, and radiator drain plug.
CAUTION:
Be sure to clean drain plug and install with new O-ring. Refer to CO-13, "
Exploded View".
If water drain plug on cylinder block is removed, close and tighten it. Refer to EM-107, "
Disassem-
bly and Assembly".
2. Check that each hose clamp is firmly tightened.
3. Remove air relief plug (1) on heater hose.
4. Fill radiator, and reservoir tank, to specified level. Pour engine coolant through engine coolant filler neck
slowly of less than 3 (2-5/8 lmp qt) a minute to allow air
in system to escape.
 Use Genuine NISSAN Long Li fe Antifreeze/Coolant or
equivalent mixed with water (dis tilled or demineralized).
Refer to MA-10, "
Fluids and Lubricants".
5. When engine coolant overflows air relief hole on heater hos e, install air relief plug with clamp. Then refill
radiator with engine coolant.
6. Install radiator cap.
7. Install reservoir tank cap.
8. Warm up engine until opening thermostat less than 3,000 rpm.  Check thermostat opening condition by touching radiat or hose (lower) to see a flow of warm water.
CAUTION: : 1.96 N·m (0.2 kg-m, 17 in-lb)
2. Engine cover
: Vehicle front
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Engine coolant capacity : Refer to CO-23,
"PeriodicalMaintenanceS
pecification".
(With reservoir tank at
“MAX” level)JPBIA0412ZZ
Reservoir tank engine
coolant capacity :Refer to
CO-23,
"PeriodicalMaintenanceSp
ecification".
(At “MAX” level)
A : MAX
B: MIN
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Revision: 2010 May2011 QX56

CO-10
< PERIODIC MAINTENANCE >
ENGINE COOLANT
Watch water temperature gauge so as not to overheat engine.
9. Stop the engine and cool down to less than approximately 50 °C (122 °F).
 Cool down using fan to reduce the time.
 If necessary, refill radiator up to filler neck with engine coolant.
10. Refill reservoir tank to “MAX” level line with engine coolant if necessary.
11. Repeat steps 6 through 10 two or more times with reservoir tank cap installed until engine coolant level no longer drops.
12. Check cooling system for leakage with engine running.
13. Warm up the engine, and check for sound of engine coolant flow while running engine from idle up to 3,000 rpm with heater temperature controller set at several position between “COOL” and “WARM”.
 Sound may be noticeable at heater unit.
14. Repeat step 13 three times.
15. If sound is heard, bleed air from cooling system by repeating step 4, and steps from 6 to 14 until engine
coolant level no longer drops.
FlushingINFOID:0000000006289660
1. Install reservoir tank if removed, and radiator drain plug. CAUTION:
Be sure to clean drain plug and install with new O-ring. Refer to CO-13, "
Exploded View".
If water drain plug on cylinder block is removed, close and tighten it. Refer to EM-107, "
Disassem-
bly and Assembly".
2. Remove air relief plug (1) on heater hose.
3. Fill radiator and reservoir tank with water until water spills from the air relief holes, then close air relief
plugs with clamp. Fill radiator and reservoir tank with water and reinstall caps.
4. Run the engine and warm it up to normal operating temperature.
5. Rev the engine two or three times under no-load.
6. Stop the engine and wait until it cools down.
7. Drain water from the system. Refer to CO-8, "
Draining".
8. Repeat steps 1 through 7 until clear water begins to drain from radiator. : 1.96 N·m (0.2 kg-m, 17 in-lb)
2. Engine cover
: Vehicle front
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Revision: 2010 May2011 QX56

RADIATORCO-11
< PERIODIC MAINTENANCE >
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RADIATOR
RESERVOIR TANK CAP
RESERVOIR TANK CAP : InspectionINFOID:0000000006289661
 Check valve seat of reservoir tank cap.
- Check if valve seat (A) is swollen to the extent that the edge of the
metal plunger (B) cannot be seen when watching it vertically from
the top.
- Check if valve seat has no soil and damage.
 Pull negative-pressure valve to open it, and check that it close completely when released.
- Check that there is no dirt or dam age on the valve seat of reservoir
tank cap negative-pressure valve.
- Check that there are no unusualness in the opening and closing conditions of negative-pressure valve.
 Check reservoir tank cap relief pressure.
- When connecting reservoir tank cap to the radiator cap tester (commercial service tool) and the r adiator cap tester adapter (com-
mercial service tool) (A), apply engine coolant to the cap seal sur-
face.
 Replace reservoir tank cap if there is an unusualness related to the above three.
CAUTION:
When installing reservoir tank cap , thoroughly wipe out the water inlet filler neck to remove any waxy
residue or foreign material.
RADIATOR
RADIATOR : InspectionINFOID:0000000006289662
Check radiator for mud or clogging. If neces sary, clean radiator as per the following:
 Be careful not to bend or damage radiator fins.
 When radiator is cleaned without removal, remove all surrounding parts such as radiator cooling fan shroud. Then tape harness and connectors to prevent water from entering.
1. Apply water by hose to the back side of the radiator core vertically downward.
2. Apply water again to all radiator core surfaces once per minute.
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SMA967B
Standard and limit : Refer to CO-23, "Radiator".
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Revision: 2010 May2011 QX56

CO-12
< PERIODIC MAINTENANCE >
RADIATOR
3. Stop washing if any stains no longer flow out from radiator.
4. Blow air into the back side of radiator core vertically downward. Use compressed air lower than 490 kPa (4.9 bar, 5 kg/cm
2, 71 psi) and keep distance more than 30 cm
(11.8 in).
5. Blow air again into all the radiator core su rfaces once per minute until no water sprays out.
Revision: 2010 May2011 QX56

RADIATORCO-13
< REMOVAL AND INSTALLATION >
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REMOVAL AND INSTALLATION
RADIATOR
Exploded ViewINFOID:0000000006289663
Removal and InstallationINFOID:0000000006289664
REMOVAL
WARNING:
Never remove radiator cap when en
gine is hot. Serious burns could occur from high-pressure engine
coolant escaping from water inlet. Wrap a thick cloth around the cap. Slowly turn it a quarter of a turn
1. Radiator cap 2. Radiator 3. Mounting rubber (upper)
4. Mounting rubber (lower) 5. Clamp 6. Radiator hose (lower)
7. O-ring 8. Drain plug 9. Fan shroud (lower)
10. Fan shroud (upper) 11. Radiator hose (upper) 12. Mounting rubber (lower)
13. Reservoir tank hose 14. Reservoir tank 15. Reservoir tank hose
16. Clamp 17. Reservoir tank cap
A. To radiator B. To water outlet C. To water inlet
Refer to GI-4, "
Components" for symbols in the figure.
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Revision: 2010 May2011 QX56