Nissan PULSAR N13 Series / ASTRA LD Series. Manual - part 19

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 ample 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 position 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 outlets 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 outer 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 hoses 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, centre 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 until 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 control 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 passenger 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 towards 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 glove 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 blower 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, condenser, 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 authorized dealer.

 

In the event of major repairs to the vehicle such as 

engine removal, the compressor 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.