coolant temperature LAND ROVER DEFENDER 1996 Workshop Manual

01INTRODUCTION
10
INFORMATION CROSS REFERENCE OF EMISSION SYSTEM
TERMINOLOGY
NEW TERM (ACRONYM)
Accelerator pedal (AP).................................................
Air cleaner (ACL)..........................................................
Air conditioning (AC)....................................................
Battery positive voltage (B+)........................................
Closed loop (CL)..........................................................
Closed throttle position (CTP)......................................
Canister purge valve (CANPV)....................................
Data link connector (DLC)...........................................
Diagnostic trouble code (DTC).....................................
Distributor ignition (DI).................................................
Engine control module (ECM)......................................
Engine coolant level (ECL)...........................................
Engine coolant temperature (ECT)..............................
Engine coolant temperature sensor (ECTS)................
Engine speed (RPM)....................................................
Evaporative emission system (EVAP)..........................
Engine fuel temperature sensor (EFTS)......................
4th gear, 3rd gear etc. (4GR, 3GR)..............................
Fuel pump (FP)............................................................
Fan control module (FCM)...........................................
Generator (GEN)..........................................................
Ground (GND)..............................................................
Heated oxygen sensor (H02S)....................................
Idle air control (IAC)......................................................
Idle air control valve (IACV).........................................
Ignition control module (ICM).......................................
Intake air temperature (IAT).........................................
Manifold vacuum zone (MVZ)......................................
Mass air flow sensor (MAFS).......................................
Open loop (OL)............................................................
Relay module (RM)......................................................
Solid state relay module (SSRM).................................
Three way catalytic converter (TWC)..........................
Throttle body (TB)........................................................
Throttle position sensor (TPS)......................................
Transmission range (TR)..............................................
Wide open throttle (WOT)............................................OLD TERM (ACRONYM)
Throttle pedal (-)..........................................................
Air cleaner (-)...............................................................
Air conditioning (AC)....................................................
Battery plus, bat +, bat feed (B+).................................
Closed loop (-).............................................................
Closed throttle, idle position (-)....................................
Charcoal canister purge valve (-).................................
Serial link (-)................................................................
Fault code (-)...............................................................
Electronic ignition (-)....................................................
Electronic control unit (ECU)........................................
Coolant level (-)...........................................................
Coolant temperature (temp).........................................
Coolant temperature thermistor (-)..............................
Engine speed (rev/min)................................................
Evaporative loss system (ELC)...................................
Fuel temperature thermistor (-)....................................
Fourth gear, 3rd gear (-)..............................................
Fuel pump (-)...............................................................
Condenser fan timer (-)................................................
Alternator (-)................................................................
Ground, earth (B-)........................................................
Lambda (02) sensor (-)................................................
Idle speed control (ISC)................................................
Stepper motor (-).........................................................
Ignition module (-)........................................................
Intake temperature/ambient temperature (-)................
Manifold depression, vacuum (-).................................
Air flow meter (-)..........................................................
Fault code display unit (-)............................................
Open loop (-)...............................................................
Relay (-).......................................................................
Control unit (-)..............................................................
Catalyst, catalytic converter (CAT)..............................
Throttle housing (-)......................................................
Transmission gear (-)...................................................
Full throttle, wide open throttle (WOT).........................

LUBRICANTS, FLUIDS AND CAPACITIES
3
INFORMATION REV: 05/99 CAPACITIES
The following capacity figures are approximate and are provided as a guide only.
Capacities (approx.)* Litres Pints
Engine sump oil 5,8................................................................ 10.20
Extra when refilling after fitting new filter 0,85.......................... 1.50
Manual gearbox 2,67............................................................... 4.70
Transfer gearbox oil 2,30......................................................... 4.00
Front differential 1,70............................................................... 3.00
Rear differential 1,70................................................................ 3.00
Power steering box and reservoir LHD 2,90............................ 5.00
Power steering box and reservoir RHD 3,40............................ 6.00
Swivel pin housing oil/grease (each) 0,35................................ 0.60
Fuel tank usable fuel 79,5........................................................ 17.5 gall
Cooling system 11,50................................................................ 20.20
Washer bottle 3,0................................................................... 5.28
NOTE: * All levels must be checked by dipstick or level plugs as applicable.
ANTI-FREEZE
PERCENTAGE CONCENTRATION - 50%
PROTECTION - LOWER TEMPERATURE LIMIT
Complete protection
Vehicle may be driven away immediately from cold,
-33°C (-36°F).
Safe limit protection
Coolant in semi-frozen state. Engine may be started
and driven away after warm-up period, -41°C (-42°
F).Lower protection
Prevents frost damage to cylinder head, block and
radiator. Thaw out before starting engine, -47°C (-53°
F).
CAUTION: Anti-freeze content must never
be allowed to fall below 25% (pre 99MY) or
50% (99MY on) otherwise damage to the
engine is liable to occur. Anti-freeze content
should not exceed 60% (all models) as this will
greatly reduce cooling efficiency.

12ENGINE
20
REPAIR OIL FILTER HEAD GASKET
Service repair no - 12.60.03
Remove
1.Clean filter head adaptor.
2.Disconnect oil cooler pipes and plug to prevent
ingress of dirt.
3.Disconnect oil pressure switch lead.
4.Remove 4 bolts and withdraw filter head,
complete with gasket.
5.Clean mating faces of filter head and cylinder
block.
6.Fit head with new gasket.
7.Tighten bolts to
45 Nm (33 lbf/ft).
8.Reconnect oil pressure switch lead.
9.Reconnect oil cooler pipes.CYLINDER HEAD GASKET
Service repair no - 12.29.02
Remove
1.Disconnect battery
2.Remove bonnet.
3.Drain coolant.
See COOLING SYSTEM,
Repair, Drain and refill cooling system
4.Remove air cleaner.See FUEL SYSTEM,
Repair, Air cleaner
5.Detach crankcase ventilation valve and side
breather hose from rocker cover and move to
one side.
6.Remove fuel injectors and pipes.
See FUEL
SYSTEM, Repair, Fuel injectors
7.Remove heater plugs.See FUEL SYSTEM,
Repair, Heater plugs
8.Disconnect radiator top hose from thermostat.
9.Disconnect bleed hose at thermostat.
10.Disconnect water pump hose at thermostat.
11.Disconnect water temperature sensor lead.

19FUEL SYSTEM
2
DESCRIPTION AND OPERATION A mechanical lift pump, with a hand priming facility, is
driven by the camshaft, and is mounted on the RH
side of the engine.
A fuel filter, with a replaceable element and
incorporating a water separator, is mounted on the
front RH side of the engine compartment.
A fuel sedimentor may be fitted when the vehicle is
operating in more arduous conditions, and is used to
minimise water deposits in the fuel system before
reaching the fuel pump and filter.
Fuel injection is carried out by a Bosch direct injection
pump, incorporating a cold start advance unit and a
high idle setting. The pump is mounted on the RH side
of the engine and is driven directly by gears in the
front cover from the crankshaft. The pump meters and
distributes fuel to 4 pintle type injectors located in
pre-combustion chambers in the cylinder head. Four
heater plugs, located in the cylinder head directly
below each injector, are fitted to improve cold starting.
An optional hand throttle, for use with a centre power
take off, is located on the fascia to the LH side of the
fuse box, and is linked independently to the fuel
injection pump throttle lever.
Air intake
The air cleaner is mounted on the RH side of the
engine and is connected by hoses to the cold air
intake duct and turbocharger inlet. Fitted between the
air cleaner and turbocharger is the crankcase breather
hose which connects to a breather filter on the rocker
cover.
A single stage turbocharger, fitted between the
exhaust manifold and exhaust down pipe, is
connected by hoses to the air cleaner and an
intercooler which is mounted on the LH side of the
radiator. The intercooler is connected by a hose to the
inlet manifold. When an EGR valve is fitted to the
turbocharger, additional pipes/hoses are used to
connect the components.Exhaust gas recirculation (EGR), when fitted.
Exhaust gas recirculation is controlled by an ECU
mounted under the front centre seat or cubby box and
receives the following inputs:
·Engine temperature from coolant temperature
sender unit on LH side of cylinder head.
·Throttle position from potentiometer on injection
pump.
·Engine speed from speedometer.
When all correct signals are received, the EGR
solenoid allows vacuum to open EGR valve and
recirculate a portion of the exhaust gas. See J6196 for
the EGR system component location and 'Operation'
for full system function.

FUEL SYSTEM
7
DESCRIPTION AND OPERATION
FUEL SYSTEM COMPONENT LOCATION
1.Fuel filter bleed screw
2.Fuel filter
3.Turbocharger
4.Actuator
5.Air cleaner
6.Fuel injector7.Heater plug
8.Heater plug controller
9.Coolant temperature transmitter
10.Fuel injection pump
11.Fuel lift pump
12.Intercooler

FUEL SYSTEM
9
DESCRIPTION AND OPERATION OPERATION
Diesel engines operate by compression ignition. The
rapid compression of air in the cylinder during the
compression cycle heats the air and when fuel is
injected into the heated air, it ignites instantaneously.
During cold tarting, automatically controlled heater
plugs assist in raising the temperature of the
compressed air to ignition point.
A cold start advance unit advances the injection timing
to further assist starting. Idle quality is improved by
the high idle setting.
The engine is supplied with pre-compressed air by a
single stage turbocharger.
Exhaust gases passing over a turbine cause it to
rotate, driving a compressor mounted on the turbine
shaft. Air drawn from the cold air intake passes, via
the air cleaner, to the turbocharger where it is
compressed. Compression in the turbocharger warms
up the air considerably, so that it expands. As a result
the air mass per cylinder is reduced, having a
negative effect on power output. By fitting a charge-air
intercooler, located on the LH side of the radiator, the
air is cooled before reaching the cylinders. This
increases power output through increased mass of
oxygen in the combustion process, as well as
maximising engine durability, through maintaining
lower piston and head temperatures.
Fuel is drawn from the tank by a mechanical lift pump
and passes to the injection pump via a filter. In
addition to removing particle contamination from the
fuel, the filter incorporates a water separator, which
removes and stores water.
The sedimentor/s, when fitted, is located adjacent to
the fuel tank/s and separates contamination and water
particles in the fuel before reaching the fuel lift pump.
The injection pump meters a precisely timed, exact
quantity of fuel to the injectors in response to throttle
variations, injection timing varying with engine speed.
Any excess fuel delivered to the injection pump is
passed back to the tank via the spill return line.
Fuel is injected in a finely atomised form into the main
combustion chamber, the burning fuel expands
rapidly, creating extreme turbulence which mixes the
burning fuel thoroughly with the compressed air,
providing complete combustion.Cold Starting is assisted by heater plugs, a cold start
advance unit and a high idle setting.
Heater plugs
Heater plug operation is controlled by a timer unit,
start relay and resistor. When the ignition is turned on
the timer unit is energised, the heater plugs start to
operate and a warning light on the dashboard
illuminates, remaining on until the heater plugs are
automatically switched off.
The length of time the heater plugs will operate is
dependent on under bonnet temperature, which is
monitored by a sensor located in the timer unit.
Starting the engine results in the power supply to the
heater plugs passing through the resistor, which
reduces their operating temperature. The heater plugs
are cut out either by the temperature sensor in the
timer, or by a microswitch on the injection pump which
operates when the throttle is depressed.
Cold start advance
The cold start advance unit is connected to the engine
cooling system via hoses. It contains a temperature
sensitive element which is retracted when cold and
pulls the advance lever, via cable, towards the rear of
the pump against spring pressure. As coolant
temperature rises, the cold start element expands
releasing tension on the cable and allowing spring
pressure to move the advance lever forwards.
Exhaust gas recirculation (EGR), when fitted
Operation of the EGR system is dependent on the
following:
·Engine temperature - must be between 20°C and
100°C approx.
·Engine speed - must be between 630 and 2850
rev/min.
·Engine load - calculated by throttle position
sensor.
·EGR valve lift position.
·Duration of engine idling.

19FUEL SYSTEM
10
DESCRIPTION AND OPERATION Under varying engine speed and load condition the
control unit sends a signal to open the vacuum
modulator which allows a vacuum to be applied above
the EGR diaphragm. The vacuum supply is taken from
a 'T' connector in the brake servo hose. This process
is controlled by an engine speed/load map stored in
the EGR control unit memory.
Engine speed is measured by monitoring the
waveform present on one phase of the generator.
Throttle position is measured via a sensor mounted on
the fuel injection pump throttle lever. Closed loop
control is achieved by allowing the control unit (ECU)
to continually monitor EGR valve lift via the sensor
mounted on the valve; this valve lift is compared with
the actual valve lift required on the control unit map
and adjusted, if necessary.
With coolant temperature between 20°C and 100°C,
the engine having just returned to idle, EGR will shut
off after 25-30 seconds idling.

COOLING SYSTEM
3
DESCRIPTION AND OPERATION COOLANT CIRCULATION
Operation
When the engine is started from cold the thermostat
(2) prevents coolant circulation through the radiator by
closing off the top hose (6). During the engine warm
up period the water pump (5) circulates coolant to the
cylinders in the crankcase and through separate ports
to the cylinder head. At the rear of the cylinder head a
proportion of the flow is diverted through a heater feed
pipe (16) to the matrix of the heater unit (15). The
coolant is then carried, via a heater return rail (14) and
hoses (7), back to the water pump. The remaining
coolant flows through a by-pass hose (9) at the
thermostat housing and back to the water pump to
complete the first cycle.
When the normal engine running temperature is
reached, the thermostat opens, closing off the by-pass
hose (9). Coolant is then circulated via the top hose
(6) and through the radiator, where it is cooled and
drawn from the radiator bottom hose (3) by the water
pump (5). The coolant circulation through the
crankcase and cylinder head remains the same.
Two bleed pipes (10) and (11) help control the system
pressure by purging excess air and coolant to the
expansion tank via the 'Y'piece ejector (12).VISCOUS FAN
Description
The viscous drive unit for the engine cooling fan,
provides a means of controlling the speed of the fan
relative to the running temperature of the engine. The
viscous unit is a type of fluid coupling, which drives
the fan blades by means of 'silicone fluid'.
1.Input (drive) member
2.Output (driven) member
3.Sensing mechanism (bi-metal coil)
The fan drive has to be engaged only periodically,
between 5% and 10%, during normal operating
conditions, because the engine is cooled by ram air
for most of the time.

COOLING SYSTEM
5
REPAIR 28.Secure steering pump and bracket to auxiliary
mounting bracket.
29.Fit steering pump pulley.
30.Fit drive belt
See ELECTRICAL, Repair,
Auxiliary drive belt
.
31.Fit fan cowl
See Fan cowl.
32.Fit viscous fan unit
See Viscous coupling and
fan
.
33.Fit intercooler top hose.
34.Fit radiator top hose.
35.Refill cooling system.
See Adjustment, Drain
and refill cooling system
36.Reconnect battery.THERMOSTAT
Service repair no - 26.45.01
Remove
1.Partially drain cooling system, until coolant level
is below thermostat housing.
2.Disconnect top hose from outlet elbow.
3.Disconnect electrical connections to water
temperature switch.
4.Unscrew 2 bolts and remove outlet elbow.
5.Withdraw thermostat. Note 88°C rating of
thermostat.
6.Place thermostat in a container half full of water.
Heat water and observe temperature at which
thermostat begins to open. Thermostat is
satisfactory if it opens between 85°-89°C.
Refit
7.Fit thermostat with jiggle pin/vent hole upwards.
8.Secure outlet elbow to thermostat housing.
Tighten bolts to
25 Nm (18 lbf/ft).
9.Fit water temperature switch connections.
10.Fit top hose to outlet elbow.
11.Refill cooling system.
See Adjustment, Drain
and refill cooling system

ELECTRICAL
3
DESCRIPTION AND OPERATION Door and bonnet switches
Perimetric protection for the vehicle is provided by
ECU inputs connected to the starter switch, bonnet
switch and door switches.
Ultrasonic sensor
The ultrasonic sensor operates by emitting an air
pressure carrier wave which is subsequently received
by the sensor as it bounces back from objects inside
the vehicle. Once armed, the alarm will sound if wave
is disturbed by a door opening, or if movement is
detected inside the vehicle.
When the volumetric sensor is activated it monitors
movement within the vehicle for 15 seconds before
detecting and responding to intrusions. If the sensor
detects movement it delays arming until a quiet period
has lapsed; if continuous movement is detected, the
alarm will not arm volumetrically.
NOTE: Interior protection will not operate
until 15 seconds after alarm is set.
The ultrasonic sensor is positioned in a different
location, according to vehicle type, as follows:
·90/110 Station Wagon - RH cantrail trim
·90/110 Pick-up - On headlining, between interior
lamp and rear view mirror
·130 Crewcab - On headlining above RH door
Alarm sounder
Two types of alarm sounder can be fitted, one with a
battery back-up facility and or without battery back-up,
both providing an audible warning whenever the alarm
is triggered. The vehicle horn will also operate if the
alarm sounds.
The alarm sounder is fitted to LH inner front wing in
the engine compartment.
NOTE: Disconnecting the battery on
vehicles fitted with the battery backed-up
facility will result in the alarm sounding, if
correct procedure has not been followed.Engine immobilisation warning light
The engine immobilisation warning light is located on
the instrument panel, and provides a visual indication
that the engine is immobilised.
Anti-theft alarm indicator light
The anti-theft alarm indicator light is located on the
instrument panel, between the fuel and coolant
temperature indicators, and provides a visual
indication of the alarm/ immobiliser status.