1987 NISSAN PULSAR Workshop Manual

Cooling and Heating Systems 73
(1) Renew all hoses that show signs of cracking
or perishing.
(2) Before finally tightening the hose clips, en-
sure that the hoses are push ed fully onto the radiator
and are not kinked. (3) On automatic transaxle models, ensure that
the oil cooler hoses are correctly installed to the
radiator and show no signs of leakage. Check and top
up the automatic transaxle fluid as necessary.
5. COOLING FAN
The radiator cooling fan is controlled by the
electronic control unit, and on vehicles with air
conditioning, the condenser fan relay. On vehicles
with air conditioning there are two cooling fans, one
is larger than the other. The large fan is for the
radiator and the smaller fan provides extra cooling
when the air conditioning is activated. Each fan is
controlled by a separate system.

TO TEST COOLING FAN AND SYSTEM
(1) With the cooling system cold and the air
conditioning, if applicable, switched off, switch the
ignition On and confirm that the cooling fan is
stationary.

NOTE: Leave the ignition On for all tests
unless otherwise stated.

(2) In the above test, if the cooling fan rotates,
proceed as follows:

(a) Disconnect the cooling fan relay from the
rear of the engine compartment relay box.
(b) If the fan stops, backprobe terminal C1 at
the electronic control unit using an LED test lamp
connected to the positive battery terminal. If no
circuit exists, renew the cooling fan relay.

View showing the location of the diagnostic link
connector. Passengers seat removed for clarity.
If a circuit exists, check the wiring harness
between the electronic control unit and the relay for
short circuits to earth and repair if necessary. If no
short circuit is present renew the electronic control
unit.


Schematic layout of the cooling fan, coolant temper-
ature sensor and related electrical components.

Installed view of the engine compartment relays. KEY

1. To Battery
2. Fusible link
COLOUR CODE
3. Fusible link
B-Black
4. Fusible linkL- Blue
5. I
gnition relayY- Yellow
6. Fuse 20 am
pW-White
7. Coolin
g fan relayO-Orange
8. Coolin
g fan
9. Coolant tem
perature
sensor
10. To air conditionin
g
fan rela
y
11. To throttle
position
sensor
12. Control unit

74 Cooling and Heating Systems
NOTE: Refer to the Fuel and Engine Man-
agement section for the correct procedure for
backprobing the control unit.

(3) In operation (1) if the cooling fan is station-
ary proceed as follows:

(a) Connect a jumper lead between the terminals
A and B of the diagnostic link connector. (b) if the fan runs, the fan circuit is satisfactory.
If the engine is overheating check the coolant temper-
ature sensor as described in the Fuel and Engine
Management section under the appropriate codes. (c) If the fan does not run, check the fuse (6) and
the fusible link (4) show n on the illustration.
(d) Backprobe terminal C1 at the electronic
control unit using an LED t est lamp connected to the
positive battery terminal. If no circuit exists, renew
the electronic control unit. (e) If the fuse and fusible links are serviceable,
ensure that power is available at the white and pink
wires from the fuse and fusible link of the cooling fan
relay. Repair any faults in the wiring to that point if
necessary. (f) Switch the ignition Off. disconnect the
cooling fan wiring connector at the radiator and
connect power to the fan. Renew the fan if it does not
run.

(4) On air conditioned models, remove the
jumper lead from the ALDL connector if still in-
stalled, start the engine and allow it to idle. Switch the
air conditioning on and ensu re that the cooling fan
runs.

If the cooling fan is opera ting as described above
but cooling system problems still exist, refer to the
Trouble Shooting heading at the start of this section.

TO REMOVE AND INSTAL COOLING FAN
(1) Disconnect the negative battery terminal.
(2) Disconnect the cooling fa n and, if applicable,
the air conditioning fan wiring connectors at the
upper edge of the radiator. (3) On models with air conditioning, remove the
compressor hose bracket bolt from the centre of the
radiator support panel.

Dismantled view of the fans and the shroud assembly. Air conditioned model.

Cooling and Heating Systems 75
(4) Remove the bolts retaining the fan shroud
assembly to the radiator and carefully move the
shroud assembly upwards and towards the engine to
release it from the lower mountings.

NOTE: On models with air conditioning, it
will be necessary to hold the air conditioning
compressor hoses toward s the engine to
allow clearance for removal of the shroud
assembly.

(5) If necessary, remove the fan from the fan
motor by removing the retaining bolts or on some
models the nut and washers.
(6) If necessary, remove the fan motor from the
shroud assembly by removing the retaining bolts or
nuts. Installation is a reversal of the removal procedure
with attention to the following points:

(1) Ensure all the fan motor and fan retaining
nuts and bolts are tightened securely. (2) Ensure that all the rubber mountings are in
good condition. Installation is a reversal of the removal procedure
with attention to the following points:

(1) Ensure that all sealing surfaces are clean.
(2) Renew the O ring on installation.
(3) Tighten the thermostat cover retaining bolts
securely.
(4) Fill the cooling system as previously de-
scribed ensuring that the heater control lever is in the
maximum heat position. Check for coolant leaks.
TO CHECK

NOTE: A visual examination of the thermo-
stat will often determine its serviceability
and make further testing unnecessary. For
instance, a thermostat with its valve fully-
open when removed from a cold engine is
obviously faulty and should be renewed.

Remove the thermostat from the thermostat
6. THERMOSTAT
Special Equipment Required:
To Check — Thermometer

TO REMOVE AND INSTAL
(1) Drain the cooling system as previously de-
scribed under the Radiator heading.
(2) On 1.6 liter models, remove the air cleaner
assembly. Refer to the Fuel and Engine Management
section if necessary. (3) Disconnect the top radiator hose from the
thermostat cover.
(4) Remove the bolts retaining the thermostat
cover to the thermostat housing. (5) Remove the thermostat cover, thermostat
and O ring from the thermostat housing.
NOTE: The thermostat and cover are ser-
viced as a unit and cannot be renewed
separately.


View of the thermostat removed from the vehicle and dismantled for testing. Line drawing showing the correct method to test the
thermostat.

(4) Progressively heat the mixture noting the
temperature reading on the thermometer as the ther-
mostat valve commences to open and when it is fully
open.

See the Specifications for opening and fully open
temperatures.

A thermostat which is not opening or is not open
at the specified temperatures should be renewed.

Cooling and Heating Systems
7. THERMOSTAT HOUSING
Special Equipment Required:
To Adjust Camshaft Drive Belt — Adjusting tool
TO REMOVE AND INSTAL
(1) Disconnect the negative battery terminal.
(2) On 1.6 liter models, remove the air cleaner
assembly from the engine. Refer to the Fuel and
Engine Management section if necessary. (3) Drain the cooling system as previously de-
scribed. (4) Remove the camshaft drive belt as described
in the Engine section under the heading Camshaft
Drive Belt. (5) Remove the bolts retaining the camshaft
drive belt rear cover to the cylinder block and remove
the rear cover.
\ COOLANT TEMPERATURE SENSOR TEMPERATURE SENDER SWITCH
View of the thermostat housing and
components.
(6) Disconnect the top radi ator hose, the heater
hose and the inlet manifold heater hose from the
thermostat housing.
(7) Disconnect the wire from the temperature
sender switch and the coolant temperature sensor. (8) Remove the bolts retaining the thermostat
housing to the cylinder head and remove the thermo-
stat housing and the O ring from the cylinder head. Installation is a reversal of the removal procedure
with attention to the following points:

(1) Ensure that all mounting faces are clean.
(2) Renew the O ring on installation.
NOTE; Ensure that the O ring is not
twisted. Do not use sealant.

(3) Tighten the thermostat housing retaining
bolts to the specified torque. (4) Adjust the camshaft drive belt tension as
described in the Engine section under the heading
Camshaft Drive Belt. (5) Fill the cooling system as previously de-
scribed and check for coolant leaks. 8. WATER PUMP

Special Equipment Required:
To Adjust Camshaft Drive Belt — Adjusting tool
TO REMOVE AND INSTAL
NOTE: The water pump is non-repairable
and if faulty must be renewed as a complete
assembly.

(1)
Drain the cooling system as previously de-
scribed.
(2) Remove the camshaft drive belt as described
in the Engine section under the heading Camshaft
Drive Belt. (3) Remove the water pump retaining bolts and
remove the water pump and the O ring from the
engine. Installation is a reversal of the removal procedure
with attention to the following points:


View of the water pump and components removed
from the vehicle.
(1) Ensure that all mounting faces are clean.
(2) Use a new O ring and smear it with a liberal
amount of silicone grease.
(3) Install the water pump to the engine but
do
not tighten the retaining bolts until the camshaft drive
belt has been installed and tensioned correctly as
described in the Engine section under the heading
Camshaft Drive Belt.
(4) Fill the cooling system as previously de-
scribed in this section and check for coolant leaks.
9. WELCH PLUGS

To facilitate the casting of the cylinder block and
cylinder head passages and water jackets, a number of
openings had to be ma de at manufacture.

Cooling and Heating Systems 77
These openings are plugged with welch plugs. The
plugs may have to be renewed when cleaning the
engine water jackets or when defective due to corro-
sion.

TO RENEW
NOTE: If a welch plug is found to be
corroded it is good policy to renew all the
welch plugs.

(1) Drain the radiator and cylinder block.
(2) Remove the necessary engine components or
accessories to gain ampl e working space around the
welch plug. (3) Using a punch and hammer, tap the welch
plug on its outer circumference into its opening. (4) Grasp the edge of the welch plug with a pair
of multi-grip pliers and using the shoulder of the pliers
as a fulcrum, lever the plug out of its opening. (5) Thoroughly clean and dry the welch plug
opening.
(6) Lightly smear the edge of a new welch plug
and the opening with Loctite 675. (7) Place the welch plug onto the opening and
using a tube or socket fitting the rim of the plug, drive
the plug squarely into its opening.
NOTE; The welch plug must be driven into
the opening straight and squarely or leaks
may occur.

(8) Install the components which were removed
to gain access to the plug. (9) Fill the cooling system as previously de-
scribed. With the reserve tank pressure cap installed,
run the engine until it reaches normal operating
temperature and check for coolant leaks.
10. HEATER UNIT, WATER VALVE AND
CONTROLS
DESCRIPTION
The heater controls use four adjustments to direct
air through the vehicle.

The air intake control selects fresh air from
outside the vehicle or recirculates air from inside the
vehicle. The recirculate position is used in dusty
conditions or to rapidly heat or cool the vehicle
interior. The fresh air positi on is the best to deodorize
the vehicle interior or demist the windscreen.

The air control lever is used to direct air to the
face outlets, the floor outle ts and the windscreen
outlets. This control also has two bi-level positions
where air may be directed to the face and floor outlets
or the windscreen and floor outlets.

The temperature control opens or shuts the heater
water valve to control the flow of engine coolant
through the heater core, which raises or lowers the
temperature of the air passing through the core.
Maximum heating is only available when the engine is
at the normal operating temperature.

The fan speed control switches the fan on and off
and is used to select the desired fan speed.

Air conditioned models use identical controls
with the addition of an air conditioner on/off button.
The centre of the button is illuminated when the air
conditioner is switched on.

Tap the welch plug on its ou ter circumference into the
cylinder block.
Using a correct fitting tube or socket, drive the welch
plug into its opening. View of the heater controls.

78 Cooling and Heating Systems
The air conditioner operates only when the engine
is running as the compressor is belt driven from the
engine.

Operating the air conditioner with the tempera-
ture control raised to a hot setting will produce
dehumidified hot air which is particularly useful for
demisting the vehicle glass.

Maximum cooling is achieved by operating the air
conditioner with the temperature control lowered
fully to the coldest setting . Operate the fan at high
speed when using the coldest temperature setting to
avoid forming ice on the evaporator.

TO REMOVE AND INSTAL HEATER UNIT
(1) Remove the dashboard as described in the
Body section. (2) Drain the cooling system as previously de-
scribed in this section. (3) Loosen the hose clamps and disconnect the
heater hoses from the heater pipes.
NOTE: If the heater hos es will not come off
the heater pipes, do not use excess force or
the heater core retaining strap will be dam-
aged. Cut the hoses from the heater pipes.

(4) Remove the steering column upper mount-
ing bolts. (5) Remove the steering column cross support
bolts and move the support towards the right hand
side of the vehicle. (6) Remove the centre support retaining bolts
and remove the centre support from the vehicle.
(7) Remove the demister duct and the right
hand side ventilator duct from the vehicle. (8) Disconnect the blower fan wiring connector
from the rear of the heater controls. (9) Remove the heater retaining bolts.
(10) On models with air conditioning, it will be
necessary to loosen the evaporator mounting bolts. (11) Working in the engine compartment, push
the heater pipe grommet through the bulkhead. (12) Maneuver the heater unit upwards slightly
and out from the bulkhead using care not to damage
the heater pipes. (13) To remove the heater core and tap assembly,
remove the screws from the retaining strap and slide
the heater core from the heater unit.
Installation is a reversal of the removal procedure
with attention to the following points:

(1 ) Before installing the heater unit to the

View of the heater unit with the dashboard, centr e support, demister duct and right hand ventilator
duct removed.

Cooling and Heating Systems 79


Front view of the heater unit showing the heater controls.
vehicle adjust the heater water tap control rod as
follows:

(a) Disconnect the control rod from the air mix
door lever.
(b) Pull the control rod un til there is a clearance
of approximately 2 mm between the end of the
control rod, which is inside the spring and the top
lever. Hold the rod in this position.
(c) Turn the air mix door lever fully anti-
clockwise and while holding the lever install the
control rod to the air mix door lever. (d) Ensure that the heater water tap is operating
correctly and shutting off correctly by blowing through
the heater pipes.
NOTE: No access to the heater water tap
control rod is possible once the heater unit is
installed in the vehicle.

(2) When maneuvering the heater unit into
position use care not to damage the heater pipes. (3) Wet the heater pipe grommets with soapy
water and install onto the heater pipes. (4) Check the heater controls for correct opera-
tion before installing the dashboard and adjust the
controls if necessary using the procedure that follows. (5) Operate the heater unit with the engine
running and ensure that the operation is satisfactory
and no leaks are present. clockwise and install the lower rod then the upper
rod
in that order.

(5)
Hold the side link fully clockwise and the
demist door lever fully anti-clockwise and install the
demist door rod. (6) Holding the side link fully clockwise, set the
air control lever on the dashboard to the face vent
position and install the air control cable to the side
link. (7) With the fan running on the high speed
setting, operate the air cont rol lever through all ranges
and ensure that the operation is correct.

Right hand side view of the heater unit.
To Adjust Temperature Control Rod and Cable
If the temperature control rod requires adjust-
ment it will be necessary to remove the heater unit
from the vehicle. Follow the procedure described
under the heading To Remove and Install Heater Unit.

(1) Working in the passenger footwell disconnect
the temperature control cable from the clip on the side
of the heater unit. (2) Set the heater controls to the maximum heat
position. (3) Hold the air mix door lever clockwise while
lightly pulling on the outer control cable to remove
slack, then install the control cable into the retaining
clip.
(4) With the engine at operating temperature
check the operation of the temperature control lever.

TO ADJUST HEATER CONTROLS
To Adjust Air Control Door Rods and Cable
(1) Disconnect the air control cable from the
side link. (2) Working on the right hand side of the heater
unit disconnect the upper and lower door lever and
demist door lever rods from the retaining clips.
(3) Hold the side link fully anti-clockwise.
(4) Hold the upper and lower door levers fully To Adjust Air Control Cable

(1)
Working in the passeng er footwell, discon-
nect the intake air control cable from the clip on the
intake unit. (2) Set the air intake lever to the recirculate
position. (3) Hold the intake lever to wards the front of the
vehicle and install the control cable into the
retaining
clip.
(4) Check the operation of the air intake control.

Cooling and Heating Systems
11. BLOWER FAN
TO REMOVE AND INSTAL
(1) Disconnect the negative battery terminal.
(2) Working below the glov e compartment, dis-
connect the wiring connector to the blower fan motor.
(3) Remove the bolts retaining the blower fan
motor and carefully lower the motor while disconnect-
ing the drain hose.

Installation is a reversal of the removal procedure
with attention to the following points:
( t ) Tighten all bolts securely.
(2) Check that the blow er fan operates correctly.

Dismantled view of the blower fan and associated
components.
12. AIR CONDITIONING
DESCRIPTION
The air conditioning system, when used in con-
junction with the heater, enables any reasonable tem-
perature to be achieved inside the vehicle. It can also
reduce the humidity of the incoming air, aiding
demisting even when cooling is not required.

The basic components of the air conditioning sys-
tem are an evaporator, co ndenser, compressor, re-
ceiver/dryer, expansion valve and pipes and hoses
carrying the refrigerant through the system. Various
subsidiary controls and sensors are also utilized to
protect the system against low or high pressure and
excessive temperature.

The refrigerant will boil at a very low tempera-
ture (-33 deg C) and therefore must be contained
under pressure. Escaping refrigerant can cause frost-
bite and eye damage and will produce a poisonous gas
when burnt. Also, if the system suffers a rapid loss of
refrigerant, oil from the compressor may be carried
out with the refrigerant. It is recommended that any
work requiring disconnection of the components be
referred to an au thorized dealer.

In the event of major repair s to the vehicle such as
engine removal, the compress or hoses are of sufficient


Schematic diagram of a typical air conditioning
system.
length to allow the compressor to be removed as the
engine is lowered from the engine compartment with-
out disturbing any refrigerant line connections.

If the operation of the air conditioning system is
in doubt, it is recommended that the vehicle be taken
to an authorized dealer for testing and repair.

TO CHECK REFRIGERANT CHARGE
(1) Start the engine and operate the air condi-
tioner on maximum cooling for a few minutes.
(2) Observe the flow of refrigerant through the
sight glass located at the top of the receiver/dryer. On
some models it may be necessary to use a mirror to
see the sight glass. (3) If the system is operating correctly, the sight
glass will be clear during the operation of the com-
pressor. Occasional bubbles may be seen when the
compressor cycles on and off during operation, but a
NUT j-
Bubbles in the sight glass when the air conditioner is
operating indicates a low refrigerant charge.