heater return LAND ROVER DISCOVERY 1995 Workshop Manual

4.0 V8
3
REPAIR ENGINE ASSEMBLY
Service repair no - 12.41.01/99
Remove
1.Position vehicle on ramp.
2.Remove bonnet.
See CHASSIS AND BODY,Repair, Bonnet [Hood]
3.Remove radiator.See COOLING SYSTEM,
Repair, Radiator
4.Remove plenum chamber.See FUEL SYSTEM
SFI, Repair, Plenum Chamber
5.Remove mass air flow sensor.See FUEL
SYSTEM SFI, Repair, Mass Air Flow Sensor
(MAF Sensor)
6.Slacken hose clip securing bottom hose to
expansion tank.
7.Disconnect hose.
8.Remove 2 nuts securing expansion tank.
9.Remove nut and bolt securing expansion tank.
10.Remove expansion tank.
11.Disconnect servo vacuum hose from ram
housing.
12.Disconnect battery sensing lead Lucar from
generator.
13.Remove generator terminal cover.
14.Remove 2 terminal nuts and release leads from
terminals.
15.Release purge hose from ram pipe housing.
16.Position cloth to absorb fuel spillage.
17.Slacken clip securing fuel return hose to fuel rail.
18.Disconnect hose.
19.Plug connections.
20.Disconnect fuel feed hose union.
21.Plug connections. Position hoses aside.
22.Slacken clip securing heater return hose to pipe.
23.Disconnect hose.24.Slacken clip securing heater feed adaptor hose
to inlet manifold.
25.Remove bolt securing pipe bracket.
26.Disconnect feed hose from inlet manifold.
27.Disconnect hose/pipe assembly.
28.Disconnect leads from spark plugs and remove
ignition coils.
See FUEL SYSTEM SFI, Repair,
Ignition Coils
29.Disconnect fuel temperature sensor multiplug.
30.Disconnect coolant sensor multiplug.
31.Disconnect temperature gauge sensor lead.
32.Release camshaft sensor multiplug from bracket
and disconnect multiplug.
33.Disconnect oil pressure switch Lucar.
34.Disconnect air intake temperature sensor
multiplug.
35.Disconnect 8 injector multiplugs.
36.Remove 4 nuts securing harness brackets to
inlet manifold.
37.Release harness brackets.
38.Remove bolts securing gearbox breather pipes
to engine lifting bracket.

4.0 V8
7
REPAIR 171.Route drive belt around pulleys.
172.Pivot tensioner downwards.
173.Align belt to tensioner and release tensioner.
174.Connect battery positive lead and tighten.
175.Secure terminal cover.
176.Align gearbox breather pipe, clip to engine lifting
eye and fit bolt. Tighten to
9 Nm.
177.Align and secure engine harness brackets to
inlet manifold and fit nuts. Tighten to
9 Nm.
178.Connect injector multiplugs.
179.Connect air intake temperature sensor multiplug.
180.Connect fuel temperature sensor multiplug.
181.Connect coolant temperature multiplug.
182.Connect temperature gauge connector.
183.Connect oil pressure switch Lucar.
184.Connect camshaft sensor multiplug and secure
to bracket.
185.Fit ignition coil bracket.
See FUEL SYSTEM
SFI, Repair, Ignition Coils
186.Position heater hose/pipe assembly.
187.Connect hose to inlet manifold.
188.Align pipe to bracket and fit bolt. Tighten to
9
Nm.
189.Tighten hose clip.
190.Connect heater return hose and tighten clip.
191.Remove plugs from fuel feed and return hose
connections.
192.Clean feed unions.
193.Connect return hose and tighten clip.
194.Connect feed hose union and tighten.
195.Remove cloth.
196.Connect purge hose.
197.Connect leads to generator, tighten terminal nuts
and fit cover.
198.Connect sensing Lucar.
199.Connect servo vacuum hose.
200.Position expansion tank and secure with fixings.
201.Connect hose and tighten clip.
202.Lower ramp.
203.Fit mass air flow sensor.
See FUEL SYSTEM
SFI, Repair, Mass Air Flow Sensor (MAF
Sensor)
204.Fit plenum chamber.See FUEL SYSTEM SFI,
Repair, Plenum Chamber
205.Fit radiator.See COOLING SYSTEM, Repair,
Radiator
206.Fit bonnet.See CHASSIS AND BODY, Repair,
Bonnet [Hood]
207.Reconnect battery negative lead.
208.Bleed power steering system.
See STEERING,
Repair, Power Steering System - Bleed
209.Drain engine oil and refill.See LUBRICANTS,
FLUIDS AND CAPACITIES, Information,
Recommended Lubricants and Fluids - USA
Vehicles
210.Start engine. Check for fuel, coolant and oil
leaks.FRONT COVER GASKET
Service repair no - 12.65.04 - Front Cover Gasket
Remove
1.Disconnect battery negative lead.
2.Drain cooling system.
See COOLING SYSTEM
V8, Adjustment, Coolant
3.Remove radiatorSee COOLING SYSTEM,
Repair, Radiator
4.Remove water pump pulley.See COOLING
SYSTEM, Repair, Viscous Coupling, Fan
Blades, Pulley and Fan Cowl
5.Slacken bottom hose clip. Remove hose from
water pump.
6.Raise vehicle on ramp.
7.Disconnect oil cooler hoses from front cover and
position aside. Plug hoses and connections.
8.Disconnect Lucar from oil pressure switch.

MFI
15
REPAIR 11.Loosen clip and disconnect top hose from
thermostat housing.
12.Disconnect multiplug from distributor amplifier
module.
13.Loosen clip and disconnect hose from heater
valve.
14.Remove injector harnesses from behind fuel rail
and lay to one side.
15.Loosen union and disconnect fuel return hose
from fuel rail.
NOTE: The intake manifold can be
removed from the cylinder block without
removing the fuel rail and injectors.
16.Using the sequence shown, remove 12 bolts
securing the intake manifold to cylinder block.
17.Remove the intake manifold.
18.Noting their fitted position, remove bolts and
clamps securing intake manifold gasket to
cylinder block.
19.Remove and discard gasket.
20.Remove and discard gasket seals.
Do not carry out further dismantling if component
is removed for access only.
21.Remove 5 nuts securing fuel rail support
brackets to intake manifold.
22.Remove fuel rail and injectors.
23.Remove 2 bolts securing thermostat housing to
intake manifold.
24.Remove thermostat housing.
25.Remove bolt securing coolant pipe to intake
manifold. Loosen union and remove coolant
pipe. Remove and discard 'O' ring.
26.Fit new 'O' ring to coolant pipe. Position coolant
pipe to intake manifold. Fit bolt securing coolant
pipe support bracket to intake manifold and
tighten pipe union.
27.Clean mating faces of thermostat housing and
intake manifold.
28.Fit thermostat housing to intake manifold using a
new gasket, fit and tighten bolts.
29.Position fuel rail to intake manifold, fit and
tighten retaining bolts.

Mpi
5
DESCRIPTION AND OPERATION
Fuel pump
The electric fuel pump, located inside the fuel tank, is
a self-priming centrifugal 'wet' pump, the motor and
pump are filled with fuel.
The fuel pump supplies more fuel than the maximum
load requirement for the engine, so that pressure in
the fuel system can be maintained under all
conditions.
Fuel pressure regulator
The pressure regulator is a mechanical device
controlled by manifold depression and is mounted in
the fuel rail. The regulator ensures that fuel rail
pressure is maintained at a constant pressure
difference to that in the inlet manifold, as manifold
depression increases the regulated fuel pressure is
reduced in direct proportion.
When pressure exceeds the regulator setting excess
fuel is spill returned to the fuel tank swirl pot which
contains the fuel pick-up strainer.
Relay module
The relay module contains the main relay, fuel pump
relay, starter relay and oxygen sensor relay and is
mounted on the ECM mounting bracket.
The main relay is energised when the ignition is
switched on and supplies current to the ECM
The fuel pump relay is energised by the ECM for a
short period when the ignition is switched on, during
cranking and while the engine is running.
The starter relay is energised by the cranking signal
from the ignition switch.
This oxygen sensor relay is energised when the
ignition is switched on and supplies current to the
ECM
Intake air temperature sensor
The intake air temperature sensor is fitted in the side
of the inlet manifold and sends the ECM a signal
relating to air temperature. The ECM uses this signal
in its calculations on air flow.
Inertia switch
The fuel pump circuit incorporates an inertia switch
which in the event of sudden deceleration isolates the
power supply to the fuel pump. The inertia switch is
situated in the engine compartment on the bulkhead
and can, if tripped, be reset by depressing the central
plunger.
WARNING: Check the integrity of the fuel
system before the inertia switch is reset.
Diagnostic connector
A diagnostic connector is provided to enable
diagnosis to be carried out without disturbing the
system electrical connections and to allow the ECM's
ability to store certain faults to be utilised.
Oxygen sensor - Closed-loop emission control
The MEMS Mpi system operates a closed loop
emission system to ensure the most efficient level of
exhaust gas conversion.
An oxygen sensor fitted in the exhaust manifold
monitors the exhaust gases. It then supplies a small
voltage proportional to exhaust oxygen content to the
ECM As the air/fuel mixture weakens, the exhaust
oxygen content increases and so the voltage to the
ECM decreases. If the mixture becomes richer so the
oxygen content decreases and the voltage increases.
The ECM uses this signal voltage to determine the
air/fuel mixture being delivered to the engine, and
adjusts the injector duration to maintain the ratio
necessary for efficient gas conversion by the catalyst.
The oxygen sensor has an integral heating element to
ensure an efficient operating temperature is quickly
reached from cold. The electrical supply for the heater
element is controlled by the oxygen sensor relay.
Fuel temperature sensor
The fuel temperature sensor is inserted in the fuel rail
and measures fuel and fuel rail temperatures. During
engine cranking at high temperatures, the ECM
increases fuel supply, and opens the throttle disc via
the stepper motor to aid hot starting.

V8i
1
DESCRIPTION AND OPERATION ENGINE COOLING
Description
The V8i engine uses a pressurised cooling system
and cross flow radiator which is supplied from a
separate header tank. The coolant radiator also
incorporates a section at the left hand end for cooling
the transmission oil and a section at the other end for
cooling the engine oil.The belt driven viscous fan and centrifugal water
pump is located in the engine front cover with ports for
circulation of coolant to both banks of cylinders and
cylinder heads. Coolant returns to the top of the
radiator via ports in the inlet manifold where the
thermostat is mounted horizontally.
Coolant also circulates through the vehicle heating
system and is used to heat air entering the inlet
manifold plenum chamber.
Coolant circulation (engine hot)
1. Cross flow radiator
2. Header tank
3. Viscous fan and water pump
4. Heater pipes
5. Plenum chamber connection
6. Thermostat

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.