NISSAN PICK-UP 1998 Repair Manual

INSPECTION
1. Check for badly rusted or corroded body assembly and vane.
2. Check for rough operation due to excessive end play.
3. Check fan coupling for rough operation, wobbling, oil leakage
or bent bimetal.
The water pump and fan coupling cannot be disassembled
and should be replaced as a unit.
SLC979
SLC244
SLC245
ENGINE COOLING SYSTEMTD
Water Pump and Cooling Fan (Camshaft
driven) (Cont'd)
LC-22

Thermostat
lAfter installation, run engine for a few minutes, and
check for leaks.
lBe careful not to spill coolant over engine compartment.
Place a rag to absorb coolant.
INSPECTION
1. Check for valve seating condition at ordinary temperatures.
It should seat tightly.
2. Check valve opening temperature and valve lift.
Tropical type Standard type
Valve opening tempera-
ture ÉC (ÉF)76.5 (170) 82 (180)
Valve lift mm/ÉC (in/ÉF)More than 8/90
(0.31/194)More than 8/95
(0.31/203)
3. Then check if valve closes at 5ÉC (9ÉF) below valve opening
temperature.
DLC007
SLC343
ENGINE COOLING SYSTEMTD
LC-23

Radiator
REMOVAL AND INSTALLATION
1. Remove under cover.
2. Drain coolant from radiator drain plug.
3. Disconnect radiator upper and lower hoses.
4. Remove radiator lower shroud.
5. Disconnect reservoir tank hose.
6. Remove radiator.
7. After repairing or replacing radiator, install any part removed
in reverse order of removal.
Refilling Engine Coolant
For details on refilling engine coolant, refer to MA section
(``REFILLING ENGINE COOLANT'', ``Changing Engine Cool-
ant'').
DLC008
ENGINE COOLING SYSTEMTD
LC-24

Wiring Diagram
HLC005
ENGINE ROOM FAN MOTOR ELECTRICAL CIRCUITTD
LC-25

Cooling Fan (Motor driven)
Electrical Components Inspection
COOLING FAN MOTOR
1. Disconnect cooling fan motor harness connector.
2. Supply cooling fan motor terminals with battery voltage and
check operation.
Cooling fan motor should operate.
If NG, replace cooling fan motor.
COOLING FAN RELAY
DLC009
DLC010
SLC143B
DLC011
ENGINE ROOM FAN MOTOR ELECTRICAL CIRCUITTD
LC-26

Check continuity between terminalsV3andV4.
Conditions Continuity
12V direct current supply between
terminals
V1andV2Yes
No current supply No
If NG, replace relay.
THERMOSWITCH
1. Disconnect thermoswitch harness connector.
2. Check operation as shown in the figure.
Coolant temperature
ÉC (ÉF)Operation Continuity
Increased to 92 - 98
(198 - 208)OFF®ON ON: Exists.
Decreased to 87 - 93
(189 - 199)ON®OFF OFF: Does not exist.
TRIPLE-PRESSURE SWITCH
For inspection of this switch, refer to HA section (``TRIPLE-
PRESSURE SWITCH'', ``Electrical Components Inspection'').
SEF440N
DLC012
SEF643Q
ENGINE ROOM FAN MOTOR ELECTRICAL CIRCUITTD
Electrical Components Inspection (Cont'd)
LC-27

Radiator (Aluminum type)
PREPARATION
1. Attach the spacer to the tip of the radiator plate pliers A.
Spacer specification: 1.5 mm (0.059 in) thick x 18 mm (0.71
in) wide x 8.5 mm (0.335 in) long.
2. Make sure that when radiator plate pliers A are closed
dimension H¢¢is approx. 7.6 mm (0.299 in).
3. Adjust dimension H¢¢with the spacer, if necessary.
lIf the radiator core rims cannot be crimped as specified,
further modification of the radiator plate pliers A is
required. Refer to the Technical Bulletin LC 91-001.
DISASSEMBLY
1. Remove tank with Tool.
lGrip the crimped edge and bend it upwards so that Tool slips
off.
Do not bend excessively.
SLC142B
SLC655C
SLC903
SLC893
ENGINE COOLING SYSTEM
LC-28

lIn areas where Tool cannot be used, use a screwdriver to
bend the edge up.
Be careful not to damage tank.
2. Make sure the edge stands straight up.
ASSEMBLY
1. Clean contact portion of tank.
2. Install sealing rubber.
Push it in with fingers.
Be careful not to twist sealing rubber.
3. Caulk tank in specified sequence with Tool.
SLC930
SLC931
SLC932
SLC917A
SLC904
ENGINE COOLING SYSTEM
Radiator (Aluminum type) (Cont'd)
LC-29

lUse pliers in the locations where Tool cannot be used.
4. Make sure that the rim is completely crimped down.
Standard height ``H'':
8.0 - 8.4 mm (0.315 - 0.331 in)
5. Confirm that there is no leakage.
Refer to Inspection.
INSPECTION
1. Apply pressure with Tool.
Specified pressure value:
157 kPa (1.57 bar, 1.6 kg/cm
2, 23 psi)
WARNING:
To prevent the risk of the hose coming undone while under
pressure, securely fasten it down with a hose clamp.
2. Check for leakage.
SLC896
SLC897
SLC554A
SLC933
SLC934
ENGINE COOLING SYSTEM
Radiator (Aluminum type) (Cont'd)
LC-30

Overheating Cause Analysis
Symptom Check items
Cooling
system parts
malfunctionPoor heat transferWater pump malfunction Worn or loose drive belt
Ð Thermostat stuck closed Ð
Damaged finsDust contamination or paper
clogging
Mechanical damage
Clogged radiator cooling tubeExcess foreign material (rust,
dirt, sand, etc.)
Reduced air flowCooling fan does not operate
ÐÐ Fan coupling does not operate
High resistance to fan rotation
Damaged fan blades
Damaged radiator shroud Ð Ð Ð
Improper coolant mixture ratio Ð Ð Ð
Poor coolant quality Ð Ð Ð
Insufficient coolantCoolant leaksCooling hoseLoose clamp
Cracked hose
Water pump Poor sealing
Radiator capLoose
Poor sealing
RadiatorO-ring for damage, deteriora-
tion or improper fitting
Cracked radiator tank
Cracked radiator core
Reservoir tank Cracked reservoir tank
Overflowing reservoir tankExhaust gas leaks into cooling
systemCylinder head deterioration
Cylinder head gasket deteriora-
tion
Except
cooling
system parts
malfunctionÐ Overload on engineAbusive drivingHigh engine rpm under no load
Driving in low gear for extended
time
Driving at extremely high speed
Powertrain system malfunction
Ð Installed improper size wheels
and tires
Dragging brakes
Improper ignition timing
Blocked or restricted air flowBlocked bumper Ð
Ð Blocked radiator grilleInstalled car brassiere
Mud contamination or paper
clogging
Blocked radiator Ð
Blocked condenser
Ð
Installed large fog lamp
ENGINE COOLING SYSTEM
LC-31