Nissan Altima L32. Instruction — part 193

OVERHEATING CAUSE ANALYSIS

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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

—

Thermostat stuck closed

Coolant circulation

Damaged fins

Dust contamination or rock
clogging

Mechanical damage

Clogged radiator cooling
tube

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

Reduced air flow

Cooling fan does not oper-
ate

Engine cooling fans

—

High resistance to fan rota-
tion

Damaged fan blades

Damaged radiator shroud

—

Radiator shroud—

—

Improper coolant mixture
ratio

—

Coolant viscosity

—

Poor coolant quality

—

Periodic maintenance

—

Insufficient coolant

Coolant leaks

Cooling hose

Loose clamp

Cracked hose

Water pump

Poor sealing

Radiator cap

Loose

Poor sealing

Radiator

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

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

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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 radiator grille

Installed car brassiere

—

Mud contamination or paper
clogging

Blocked bumper

Blocked radiator

Blocked condenser

Installed large fog lamp

Symptom

Check items

ENGINE COOLANT

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ON-VEHICLE MAINTENANCE

ENGINE COOLANT

System Inspection

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WARNING:

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

sure fluid escaping from the radiator.

• 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 reservoir tank coolant level is within MIN to MAX when

the engine is cool.

• Adjust coolant level if it is too much or too little.

CHECKING COOLING SYSTEM FOR LEAKS

To check for leakage, apply pressure to the cooling system using

suitable tool (A) and Tool (B).

WARNING:

Never remove the radiator cap when the engine is hot. Serious

burns could occur from high pressure coolant escaping from

the radiator.

CAUTION:

Higher pressure than specified may cause radiator damage.

CHECKING RADIATOR CAP

1. Inspect the radiator 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 radiator filler neck to remove any waxy residue or foreign material.

SMA412B

Tool number

: EG17650301 (J-33984-A)

Testing pressure : 157 kPa (1.6 kg/cm

2

, 23 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

radiator cap negative-pressure valve.

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

ing conditions of the negative-pressure valve.

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

• When connecting the radiator cap to the tester, apply water or

coolant to the cap seal surface.

• Replace the radiator cap if there is an abnormality in the nega-

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

the standard values.

CHECKING RADIATOR

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

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

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

horns. Then tape the harness and electrical connectors to prevent water from entering.

1. Apply water by hose to the back side of the radiator core, with the hose pointed vertically downward.
2. Apply water again to all radiator core surfaces once per minute.
3. Stop washing if any stains no longer flow out from the radiator.
4. Blow air into the back side of radiator core, with the air hose pointed vertically downward.

• Use compressed air lower than 490 kPa (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 surfaces once per minute until no water sprays out.
6. Check for leaks.

Changing Engine Coolant

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WARNING:

• To avoid being scalded, never change the coolant when the engine is hot.

• Wrap a thick cloth around cap and carefully remove the cap. First, turn the cap a quarter of a turn to

release built-up pressure. Then push down and turn the cap all the way to remove.

DRAINING ENGINE COOLANT

1. Remove the engine undercover using power tool.
2. Open the radiator drain plug at the bottom of the radiator and remove the radiator filler cap. This is the

only step required when partially draining the cooling system (radiator only).

CAUTION:

Do not allow the coolant to contact the drive belts.

3. Follow this step for heater core removal/replacement only. Disconnect the upper heater hose at the

engine side and apply moderate air pressure [103.46 kPa (15 psi, 1.055 kg/cm

2

) maximum air pressure]

into the hose for 30 seconds to blow the excess coolant out of the heater core.

4. When draining all of the coolant in the system, remove the reservoir tank and drain the coolant, then clean

the reservoir tank before installation.

SMA967B

Tool number

: EG17650301 (J-33984-A)

Standard: 122.3 – 151.7 kPa (1.2 – 1.5 kg/cm

2

, 18 – 22 psi)

Limit: 107 kPa (1.1 kg/cm

2

, 16 psi)

WBIA0570E