Nissan Pathfinder (2012 year). Instruction — part 130

COOLING SYSTEM

CO-37

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SYSTEM DESCRIPTION

COOLING SYSTEM

Cooling Circuit

INFOID:0000000007357927

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1.

Cylinder head (LH)

2.

Water cut valve

3.

Cylinder head (RH)

4.

Oil cooler

5.

Reservoir tank

6.

Cylinder block (RH)

7.

Thermostat

8.

Water pump

9.

Cylinder block (LH)

10. Radiator

A.

From heater

B.

To electronic throttle control actuator

C.

To heater

D.

From electronic throttle control actuator

August 2012

2012 Pathfinder

CO-38

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COOLING SYSTEM

Schematic

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1.

Radiator

2.

Reservoir tank

3.

Thermostat and thermostat housing

4.

Water pump

5.

Cylinder block

6.

Cylinder head

7.

Water cut valve

8.

Heater

9.

Electronic throttle control actuator

10. Oil cooler

A.

Thermostat closed

B.

Thermostat open

August 2012

2012 Pathfinder

OVERHEATING CAUSE ANALYSIS

CO-39

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OVERHEATING CAUSE ANALYSIS

Troubleshooting Chart

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Symptom

Check items

Cooling sys-
tem parts
malfunction

Poor heat transfer

Water pump malfunction

Worn or loose drive belt

—

Coolant circulation

Thermostat stuck closed

Damaged fins

Dust contamination or pa-
per clogging

Physical damage

Clogged radiator cooling
tube

Excess foreign material
(rust, dirt, sand, etc.)

Water cut valve malfunction

Physical damage

Reduced air flow

Cooling fan does not oper-
ate

Fan assembly

—

High resistance to fan rota-
tion

Damaged fan blades

Damaged radiator shroud

—

Radiator shroud

—

Improper engine coolant
mixture ratio

—

Engine coolant viscosity

—

Poor engine coolant quality

—

—

Insufficient engine coolant

Engine coolant leaks

Cooling hose

Loose clamp

Cracked hose

Water pump

Poor sealing

Radiator or reservoir cap

Loose

Poor sealing

O-ring for damage, deterio-
ration or improper fitting

Radiator

Cracked radiator tank

Cracked radiator core

Reservoir tank

Cracked reservoir tank

Overflowing reservoir tank

Exhaust gas leaks into cool-
ing system

Cylinder head deterioration

Cylinder head gasket deteri-
oration

August 2012

2012 Pathfinder

CO-40

< SYSTEM DESCRIPTION >

[VK56DE]

OVERHEATING CAUSE ANALYSIS

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

Installed car brassiere

—

Blocked radiator grille

Mud contamination or paper
clogging

Blocked radiator

Blocked condenser

Blocked air flow

Installed large fog lamp

Symptom

Check items

August 2012

2012 Pathfinder

ENGINE COOLANT

CO-41

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PERIODIC MAINTENANCE

ENGINE COOLANT

System Inspection

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WARNING:

• Never remove the radiator/reservoir cap when the engine is hot. Serious burns could occur from

high pressure fluid escaping from the radiator or reservoir.

• Wrap a thick cloth around the cap. Slowly push down and turn it a quarter turn to allow built-up pres-

sure to escape. Carefully remove the cap by pushing down and turning it all the way.

CHECKING COOLING SYSTEM HOSES

Check hoses for the following:

• Improper attachment

• Leaks

• Cracks

• Damage

• Loose connections

• Chafing

• Deterioration

CHECKING RESERVOIR LEVEL

• Check if the engine coolant reservoir tank level is within MIN to

MAX level when the engine is cool.

• Adjust engine coolant level as necessary.

CHECKING COOLING SYSTEM FOR LEAKS

WARNING:

Never remove the radiator/reservoir cap when the engine is hot. Serious burns could occur from high-

pressure engine coolant escaping from the radiator or reservoir.

• To check for leakage, apply pressure to the cooling system at the

reservoir filler neck using suitable tool (A) and Tool (B).

CAUTION:

Higher pressure than specified may cause radiator damage.

NOTE:

In case that engine coolant decreases, replenish cooling system

with engine coolant.

• If any concerns are found, repair or replace damaged parts.

CHECKING RESERVOIR CAP

1. Inspect the reservoir cap.

• Replace the cap if the metal plunger cannot be seen around the edge of the black rubber gasket.

• Replace the cap if deposits of waxy residue or other foreign material are on the black rubber gasket or

the metal retainer.

NOTE:

Thoroughly wipe out the reservoir filler neck to remove any waxy residue or foreign material.

SMA412B

Tool number

: — (J-24460-92)

Testing pressure

: 137 kPa (1.4 kg/cm

2

, 20 psi)

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ENGINE COOLANT

2. Pull the negative-pressure valve to open it and check that it

closes completely when released.

• Check that there is no dirt or damage on the valve seat of the

reservoir cap negative-pressure valve.

• Check that there are no abnormalities in the opening and clos-

ing conditions of the negative-pressure valve.

3. Check reservoir cap relief pressure using suitable tool and Tool.

NOTE:

• Apply engine coolant to the cap seal surface.

• Replace the reservoir cap if there is any damage in the nega-

tive-pressure valve, or if the open-valve pressure is outside of

the limit.

CHECKING RADIATOR CAP

Inspect the radiator cap.

NOTE:

Thoroughly wipe out the radiator filler neck to remove any waxy residue or foreign material.

• Replace the cap if deposits of waxy residue or other foreign material are on the black rubber gasket or the

metal retainer.

CHECKING RADIATOR

Check radiator for mud or clogging. If necessary, clean radiator as follows.

CAUTION:

• Be careful not to bend or damage the radiator fins.

• When radiator is cleaned without removal, remove all surrounding parts such as cooling fan, radia-

tor shroud and horns. Then tape the harness and electrical connectors to prevent water from enter-

ing.

1. Spray water to the back side of the radiator core using a side to side motion from the top down.
2. Stop spraying when debris no longer flows from radiator core.
3. Blow air into the back side of radiator core using a side to side motion from the top down.

• Use compressed air lower than 490 kPa (5 kg/cm

2

, 71 psi) and keep distance more than 30 cm (11.8 in).

4. Continue to blow air until no water sprays out.
5. Check for coolant leaks. Repair as necessary.

Changing Engine Coolant

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WARNING:

Do not remove the radiator cap when the engine is hot. Serious burns could occur from high-pressure

engine coolant escaping from the radiator. Wrap a thick cloth around the radiator cap. Slowly turn it a

quarter of a turn to release built-up pressure. Carefully remove radiator cap by turning it all the way.

DRAINING ENGINE COOLANT

1. Turn ignition switch ON and set temperature control lever all the way to HOT position or the highest tem-

perature position. Wait 10 seconds and turn ignition switch OFF.

2. Remove the engine under cover using power tool.

SMA967B

Tool number

: — (J-33984-A)

Standard: 98 – 118 kPa (1.0 – 1.2 kg/cm

2

, 14 – 17 psi)

WBIA0570E

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ENGINE COOLANT

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3. Open the radiator drain plug at the bottom of the radiator, and

remove the reservoir cap. This is the only step required when

partially draining the cooling system (radiator only).

CAUTION:

• Perform this step when the engine is cold.

• Do not to allow the coolant to contact the drive belts.

4. When draining all of the coolant in the system for engine it is

necessary to drain the cylinder block. Remove the RH cylinder

block drain plug to drain the right bank, the oil cooler hose to

drain the left bank as shown.

CAUTION:

Do not reuse copper sealing washers.

NOTE:

For Canada, the drain plug as shown is replaced by a block

heater.

5. Remove the reservoir tank to drain the engine coolant, then clean the reservoir tank before installing it.
6. Check the drained coolant for contaminants such as rust, corrosion or discoloration.

If the coolant is contaminated, flush the engine cooling system. Refer to

CO-42, "Changing Engine Cool-

ant"

.

REFILLING ENGINE COOLANT

1. Close the radiator drain plug. Install the reservoir tank, cylinder

block drain plug, and the oil cooler hose.

• The radiator must be completely empty of coolant and water.

• Apply sealant to the threads of the cylinder block drain plug.

Use Genuine High Performance Thread Sealant or equivalent.

Refer to

GI-14, "Recommended Chemical Products and Seal-

ants"

.

CAUTION:

Do not reuse copper sealing washers.

2. Set the vehicle heater controls to the full HOT and heater ON position. Turn the vehicle ignition ON with

the engine OFF as necessary to activate the heater mode.

LLIA0070E

PBIC0146E

WBIA0392E

Radiator drain plug

: Refer to

CO-42, "Changing

Engine Coolant"

.

RH cylinder block drain
plug

: Refer to

EM-228, "Disassem-

bly and Assembly"

.

WBIA0392E

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ENGINE COOLANT

3. Remove the vented reservoir cap and replace it with a non-vented reservoir cap before filling the cooling

system.

4. Install the Tool by installing the radiator cap adapter onto the

radiator neck opening. Then attach the gauge body assembly

with the refill tube and the venturi assembly to the radiator cap

adapter.

5. Insert the refill hose into the coolant mixture container that is

placed at floor level. Make sure the ball valve is in the closed

position.

•

Use recommended coolant or equivalent. Refer to

MA-18,

"FOR USA AND CANADA : Fluids and Lubricants"

(United

States and Canada) or

MA-20, "FOR MEXICO : Fluids and

Lubricants"

(Mexico).

6. Install an air hose to the venturi assembly, the air pressure must

be within specification.

CAUTION:

The compressed air supply must be equipped with an air dryer.

7. The vacuum gauge will begin to rise and there will be an audible hissing noise. During this process open

the ball valve on the refill hose slightly. Rising coolant will be visible in the refill hose. After the refill hose is

full of coolant, close the ball valve. This will purge air trapped in the refill hose.

8. Continue to draw the vacuum until the gauge reaches 28 inches

of vacuum. The gauge may not reach 28 inches in high altitude

locations. Refer to the following table for expected vacuum read-

ings.

9. When the vacuum gauge has reached the specified amount, disconnect the air hose and wait 20 seconds

to see if the system loses vacuum. If the vacuum level drops, perform necessary repairs to the system

and repeat steps 6 - 8 to bring the vacuum to the specified amount. Recheck for leaks.

10. Place the coolant container (with the refill hose inserted) at the same level as the top of the radiator. Then

open the ball valve on the refill hose so the coolant will be drawn up to fill the cooling system. The cooling

system is full when the vacuum gauge reads zero.

CAUTION:

Do not allow the coolant container to get too low when filling, to avoid air from being drawn into

the cooling system.

11. Remove the Tool from the radiator neck opening and install the radiator cap.
12. Remove the non-vented reservoir cap.
13. Fill the cooling system reservoir tank to the specified level. Run the engine to warm up the cooling system

and top up the system as necessary before installing the vented reservoir cap.

14. Install the engine under cover or skid plate. Refer to

EXT-15, "Removal and Installation"

.

FLUSHING COOLING SYSTEM

Tool number

: KV991J0070 (J-45695)

Cooling system capacity
(with reservoir)

: Refer to

CO-56, "Stan-

dard and Limit"

.

Compressed air
supply pressure

: 549 - 824 kPa (5.6 - 8.4 kg/cm

2

,

80 - 119 psi)

LLIA0058E

Altitude above sea level

Vacuum gauge reading

0 - 100 m (328 ft)

: 28 inches of vacuum

300 m (984 ft)

: 27 inches of vacuum

500 m (1,641 ft)

: 26 inches of vacuum

1,000 m (3,281 ft)

: 24 - 25 inches of vacuum

LLIA0057E

August 2012

2012 Pathfinder