coolant temperature LAND ROVER DISCOVERY 1995 Repair Manual

26COOLING SYSTEM
4
REPAIR RADIATOR
Service repair no - 26.40.01
Remove
1.Drain cooling system.
See Adjustment,
Coolant
2.Remove viscous coupling and fan assembly.
See Viscous Coupling, Fan Blades, Pulley
and Fan Cowl
3.Release 2 clips and remove fan cowl.
4.Disconnect radiator top hoses.
5.Disconnect four transmission and engine oil
cooler connections to radiator end tanks. Note oil
spillage will occur when connections are
loosened. Blank off exposed oil connections.
6.Disconnect transmission oil temperature sensor.
7.Remove radiator securing brackets from each
side.
8.Remove radiator unit by lifting from its location.
Check condition of rubber mounting pads.Refit
9.Reverse removal procedure.
10.Clean unions and apply sealant.
11.Lubricate new 'O' rings before fitting.
12.Check radiator sealing strips are securely
located.
13.Transfer oil cooler adaptors if fitting new radiator.
14.Ensure that oil cooler connections are tightened
to
30 Nm.before fitting fan blades and cowl.
15.Clean coolant/oil spillage from vehicle.
16.Check all connections for coolant/oil leaks.

MANIFOLD AND EXHAUST SYSTEM
5
REPAIR INLET MANIFOLD GASKET - Mpi
Service repair no - 30.15.08
Remove
1.Disconnect battery negative lead.
2.Position absorbent cloth around fuel pipe to fuel
rail union. Unscrew union to relieve fuel
pressure. Re-tighten union.
CAUTION: Plug connections.
3.Release clip and remove air cleaner to throttle
housing hose.
4.Disconnect stepper motor multiplug.
5.Disconnect throttle potentiometer multiplug.
6.Release throttle cable from abutment bracket.
7.Release throttle cable from cam. Remove
coolant bypass hose.
8.Disconnect fuel temperature sensor multiplug.
9.Release clip and disconnect brake servo hose
from manifold.

MANIFOLD AND EXHAUST SYSTEM
7
REPAIR Refit
19.Ensure mating faces of inlet manifold and
cylinder head are clean.
20.Fit a new gasket, position inlet manifold to
cylinder head.
21.Fit nuts and bolts, tighten in the order shown to
the correct torque
25Nm
22.Position engine breather hose to manifold and
secure with bolts.
23.Connect fuel injector harness and intake air
temperature sensor multiplug.
24.Connect fuel hose to pressure regulator and
secure with clip.
25.Fit fuel pipe to fuel rail, tighten union to
10Nm
26.Connect vacuum hoses to manifold.
27.Position engine harness and cam cover brackets
to manifold, secure with bolts.
28.Connect breather hose and brake servo hose to
manifold, secure with clips.
29.Connect multiplug to fuel temperature sensor.
30.Connect breather hose to throttle housing and
secure with clip.
31.Connect throttle cable to cam and secure to
abutment bracket.
32.Connect coolant bypass hose to throttle housing.
33.Connect stepper motor and throttle
potentiometer multiplugs.
34.Connect air cleaner hose to throttle housing and
secure with clip.
35.Connect battery negative lead.
36.Adjust throttle cable.EXHAUST MANIFOLD GASKET - Mpi
Service repair no - 30.15.12
Remove
1.Raise vehicle.
2.Loosen 2 nuts securing downpipe to silencer
box.
3.Remove 4 nuts securing downpipe to exhaust
manifold.
4.Release downpipe from exhaust manifold.
5.Discard gasket.

MANIFOLD AND EXHAUST SYSTEM
9
REPAIR MANIFOLD CHAMBER GASKET - Mpi
Service repair no - 30.15.37
Remove
1.Disconnect battery negative lead.
2.Position absorbent cloth around fuel pipe to fuel
rail union. Loosen union to relieve pressure.
Re-tighten union.
3.Release clip and remove air cleaner to throttle
housing hose.
4.Disconnect stepper motor and throttle
potentiometer multiplugs.
5.Release clip and disconnect breather hose from
throttle housing.
6.Release throttle cable from abutment bracket.
7.Release throttle cable from cam. Remove
coolant bypass hose from throttle housing.
8.Disconnect fuel temperature sensor multiplug.
9.Release clip and disconnect brake servo hose
from manifold.

30MANIFOLD AND EXHAUST SYSTEM
10
REPAIR 10.Release clip and disconnect breather hose from
manifold.
11.Release 2 bolts securing camshaft cover
brackets to manifold.
12.Disconnect 4 vacuum hoses from manifold.
13.Remove 6 bolts securing manifold chamber to
lower manifold.
14.Remove manifold chamber and collect gaskets.
Refit
NOTE: For torque values.See
Specifications, torque, Torque Values
15.Ensure mating faces of manifold chamber and
lower manifold are clean.
16.Fit a new gasket, position manifold chamber to
lower manifold.
17.Fit bolts, tighten to the correct torque.
18.Connect vacuum hoses to manifold.
19.Position camshaft cover brackets to manifold,
secure with bolts.
20.Connect breather hose and brake servo hose to
manifold, secure with clips.
21.Connect multiplug to fuel temperature sensor.
22.Connect breather hose to throttle housing and
secure with clip.
23.Connect throttle cable to cam and secure to
abutment bracket.
24.Connect coolant bypass hose to throttle housing.
25.Connect stepper motor and throttle
potentiometer multiplugs.
26.Connect air cleaner hose to throttle housing and
secure with clip.
27.Reconnect battery negative lead.
28.Adjust throttle cable.

HEATING AND VENTILATION
3
DESCRIPTION AND OPERATION
Controls set for unheated air to footwells and face level vents
Heater and ventilation operation
The heating and ventilation system contains a heater
matrix, which is connected to the engine cooling
system, and a 4 speed fan for air distribution. Engine
coolant is circulated through the heater matrix
continuously, except when the temperature controls
are set to COLD.
Recirculated air
When the recirculation switch is pressed, an electrical
servo operates and fully closes the fresh air intake
flap.
Fresh air
When the recirculation switch is returned to the OFF
position, the electrical servo returns and fully opens
the fresh air intake flap.Heated air
Temperature output is controlled by the temperature
controls which move the air direction and temperature
flaps independently to increase or decrease the
volume of air flow through the heater matrix.
V8 Engine:When both controls are in the cold
position, the coolant valve is turned off.
Face level vent flap
Control at face level, flap fully open. All other vents
closed.
Control at face and foot level, flaps half open.
Unless an air conditioning unit is fitted, only fresh or
re-circulated air is available from the face level vents.
Demist vent flap
Control at demist, flap fully open. All other vents
closed.
Control at demist and foot level, flaps half open.

80HEATING AND VENTILATION
4
DESCRIPTION AND OPERATION Air direction flap
Flap moves across mixing chamber to direct the air
flow away from the heater matrix.
Air temperature flap
Control at HOT, flaps fully closed. All air flow passes
through heater matrix. As control is moved towards
COLD the flaps progressively open directing air flow
away from the heater matrix.
Control at COLD, flaps fully open.
V8 Engine:When both controls are at COLD, 2
micro-switches are closed and operate a vacuum
valve which closes the coolant valve.Air conditioning
When an air conditioning unit is fitted, the mechanical
operation of the heater controls remains unaltered.
However the air conditioning evaporator is positioned
in front of the mixing chamber through which all air
flow passes.

HEATING AND VENTILATION
1
FAULT DIAGNOSIS HEATER OUTPUT
Symptom:-
Heater emits cold air.
1.Engine running: Check coolant valve opens as a
temperature control is moved from COLD.
2.Check for engine running cold.
See COOLING
SYSTEM, Fault diagnosis, Engine Runs Cold
3.Check heater pipes and hoses for blockage or
restriction.
4.Check heater matrix for blockage or restriction,
flush system.
Heater emits warm air.
5. Engine running:Check coolant valve closes
when both temperature controls are moved to
COLD.

AIR CONDITIONING
3
DESCRIPTION AND OPERATION AIR CONDITIONING SYSTEM OPERATION
The air conditioning system provides the means of
supplying cooled and dehumidified, fresh or
recirculated air to the interior of the vehicle. The
cooling effect is obtained by blowing air through the
matrix of an evaporator unit and when required,
mixing that air with heated air by means of the heater
distribution and blend unit, to provide the conditions
required inside the vehicle. The volume of conditioned
air being supplied is controlled by a variable speed
blower.
A sealed system, charged with Refrigerant R134a,
together with a blower unit, blend unit and control
system combine to achieve the cooled air condition.
For air conditioning air distribution system.
See
HEATING AND VENTILATION, Description and
operation, Heating and ventilation unit
The air conditioning system comprises five major
units:
1.An engine-mounted compressor.
2.A condenser mounted in front of the radiator.
3.A receiver/drier unit located in front of the
condenser.
4.Thermostatic expansion valve mounted above
the evaporator.
5.An evaporator unit mounted in front of the heater
matrix.
NOTE: Vehicles fitted with rear air
conditioning have an additional
evaporator/blower motor assembly located
behind the LH rear compartment lower trim panel.
These units are interconnected by hoses and pipes
carrying Refrigerant R134a, the evaporator is linked
into the vehicle ventilation system.
Refrigeration cycle
1. Compressor
The compressor (1), belt driven from the crankshaft
pulley, pressurises and circulates the refrigerant
through the system. Mounted on the compressor, an
electro-mechanical clutch maintains the correct
temperature and pressure by engaging or disengaging
to support the system's requirements. The clutch
action is normally controlled by a thermostat located
at the evaporator (5). The compressor is of the
swashplate type having fixed displacement.Should the temperature at the evaporator (5) fall low
enough for ice to begin to form on the fins, the
thermostat disengages the clutch and also isolates the
cooling fans relays. When the temperature at the
evaporator (5) rises to the control temperature, the
clutch is re-engaged.
Should the system pressure become excessive or
drop sufficiently to cause damage to the compressor
(1) a dual pressure switch (7), located in the high
pressure line, signals the relay unit to disengage the
clutch. The compressor also has an emergency high
pressure relief valve (9) fitted.
The cooling fans are controlled by engine temperature
when the air conditioning is not switched on.
2. Condenser
From the compressor, hot high pressure vaporised
refrigerant (F1) passes to the condenser (2), which is
mounted in front of the engine coolant radiator. Ram
air(A1) passing through the condenser (2),
supplemented by 2 cooling fans (8) mounted in front
of the condenser, cools the refrigerant vapour
sufficiently to form a high pressure slightly subcooled
liquid (F2).
3. Receiver/drier
This liquid then passes to a receiver/drier (3) which
fulfils two functions. It acts as a reservoir and moisture
extractor (11).
A sight glass (10), in the high pressure line, provides a
method of determining the state of the refrigerant
without breaking into the system.
4. Expansion valve
From the receiver/drier (3) the moisture free high
pressure liquid refrigerant (F3) passes through a
thermostatic expansion valve (4). A severe pressure
drop occurs across the valve and as the refrigerant
enters the evaporator space at a temperature of
approximately -5°C it boils and vaporises.

82AIR CONDITIONING
4
DESCRIPTION AND OPERATION 5. Evaporator
As this change of state occurs, a large amount of
latent heat is absorbed. The evaporator is therefore
cooled and as a result heat is extracted from the air
flowing across the evaporator. The air flow is
controlled by the ventilation fan which can be
operated at anyone of four speeds.
To prevent liquid passing through to the compressor,
a capillary tube (6), attached to the outlet pipe of the
evaporator (5) and connected to the thermostatic
expansion valve (4), controls the amount that the
valve opens and closes in relation to the temperature
of the low pressure high temperature refrigerant
vapour (F4) at the outlet. The atomised refrigerant
then passes through the evaporator (5). Fan blown air
(A2) passes through the matrix (A3) of the evaporator
and is cooled by absorption due to the low
temperature refrigerant passing through the
evaporator.
A thermostat is fitted in the airflow out of the
evaporator to sense the temperature of the exterior
fins. Should ice begin to form, due to a too cold
condition, it will signal to disengage the
electro-mechanical clutch on the compressor (1).
From the evaporator, low pressure slightly
superheated refrigerant (F5) passes to the
compressor to complete the cycle.AIR CONDITIONING CONTROL SYSTEM
The air conditioning control system comprises relays,
thermostat, pressure switches, and a control panel.
Inputs from outside the air conditioning system
comprise temperature information from the engine
cooling system. Together these controls, in
conjunction with the cooling fans, compressor clutch,
blower and heater distribution and blend unit enable
minimal input to maintain the required environment
inside the vehicle.
When air conditioning is not selected, air is supplied
by ram effect or blower to the areas selected by the
controls. The air mix flap on the blend unit controls the
temperature of the air being supplied. No cooled air is
available.
Selecting air conditioning provides the added facility of
cooled air available to be mixed as before. When
required a fully cold condition can be selected by
turning the temperature controls to cold, which
automatically closes the heated coolant access to the
heater matrix. Mixtures of cooled, fresh, and hot air
can be selected to give required interior environmental
conditions by selection at the control panel.
Dual pressure switch
This switch, located in the high pressure line between
the receiver drier and the expansion valve, monitors
refrigerant pressure and by means of the relay module
controls the following system functions:
1.Refrigerant pressure drops below 2.0 bar, 29
lbf/in
2(due to possible leakage), the
compressor's electro-mechanical clutch is
dis-engaged.
When pressure rises above 2.0 bar, 29 lbf/in
2the
compressor's clutch is re-engaged.
2.Refrigerant pressure rises above 32 bar, 455
lbf/in
2(due to possible blockage), even with
cooling fan operation, the compressor's
electro-mechanical clutch is dis-engaged.
When the pressure drops below 26 bar, 375
lbf/in
2the compressor clutch is re-engaged.