1999 LAND ROVER DEFENDER wheel

ENGINE
21
OVERHAUL
7.Using sequence shown, tighten sump bolts to25
Nm (18 lbf.ft).
8.Fit new centrifuge oil drain pipe gasket.
CAUTION: Gasket must be fitted dry.
9.Fit centrifuge oil drain pipe, fit bolts and tighten
to10 Nm (7 lbf.ft).SEAL - CRANKSHAFT - REAR
Service repair no - 12.21.20.01
Remove
1.Remove flywheel.See Repair.
2.Remove sump gasket.See this Section.
3.Remove 5 bolts securing crankshaft rear oil seal
housing to cylinder block.
4.Remove and discard crankshaft rear oil seal and
housing.
NOTE: Dowel located.
ProCarManuals.com

12ENGINE
22
OVERHAUL Refit
1.Clean crankshaft rear oil seal housing mating
face on cylinder block, ensure bolt and dowel
holes are clean and dry. Remove all traces of oil
from oil seal running surface on crankshaft.
2.Position seal protectorLRT-12-061over
crankshaft boss. Fit new seal and housing,
removeLRT-12-061.
CAUTION: Oil seal must be fitted dry.
3.Fit oil seal housing bolts and using sequence
shown, tighten to9 Nm (7 lbf.ft).
4.Fit sump gasket.See this Section.
5.Fit flywheel.See Repair.STARTER RING GEAR
Service repair no - 12.53.19
Remove.
1.Remove flywheel.See Repair.
2.Drill a 3 mm (0.12 in) diameter hole at root of 2
teeth.
3.Apply a cold chisel to root of teeth, break ring
gear and remove from flywheel.
WARNING: SUITABLE EYE PROTECTION
MUST BE WORN.
Refit
1.Heat ring gear evenly to 350°C, indicated by
light blue colour.
2.Locate ring gear on flywheel and press on to
flange.
WARNING: Handle hot ring gear with care.
3.Allow ring gear to air cool.
4.Fit flywheel.See Repair.
ProCarManuals.com

18ENGINE MANAGEMENT SYSTEM
12
DESCRIPTION AND OPERATION SENSOR - CRANKSHAFT SPEED AND
POSITION (CKP)
The CKP sensor is located in the transmission housing with its tip adjacent to the outer circumference of the
flywheel. The CKP sensor works on the variable reluctance principal, which sends a signal back to the ECM in the
form of an ac voltage.
The ECM uses the signal from the CKP sensor for the following functions.
To calculate engine speed.
To determine engine crank position.
To determine fuel injection timing.
The CKP sensor works as a Variable Reluctance Sensor (VRS). It uses an electromagnet and a target ring to
generate a signal. As the target ring passes the tip of the CKP sensor the magnetic field produced by the sensor is
cut and then re-instated. The ECM measures the signal as an ac voltage.
The outer circumference of the flywheel acts as the target ring for the sensor. The flywheel is divided into 36
segments, each of 10°. 31 segments have drilled holes and 5 segments are spaces. This equals 360°or one
engine revolution. The 5 spaces correspond to the TDC position of the 5 cylinders. This allows the ECM to control
fuel injection timing for each of the cylinders.
Inputs / Outputs
The two pins of the CKP sensor (C1068-1 & C1068-2) are both outputs. The ECM (C0158-13 & C0158-36)
processes the outputs of the sensor. To protect the integrity of the CKP sensor signal, an earth screen is used.
The ECM measures the outputs from the CKP sensor. The ECM (C0158-13) measures a positive signal on a
pink/black wire, and a negative signal (C0158-36) on a white/blue wire. The earth path for the sensor is via the
ECM (C0158-16).
ProCarManuals.com

19FUEL SYSTEM
2
DESCRIPTION AND OPERATION DESCRIPTION
General
The fuel delivery system comprises a fuel tank, fuel pump, fuel pressure regulator, five injectors and a fuel filter.
The system is controlled by the ECM, which energises the fuel pump relay and controls the operation and timing
of each injector solenoid.
Unlike other Diesel engines, the Td5 has no injection pump. The diesel direct injection system receives fuel at
pressure from a two stage fuel pump located in the fuel tank. The system incorporates a fuel return to the fuel
pump, via a fuel cooler attached to the inlet manifold, and a fuel filter. A fuel pressure regulator is located in a
housing on the rear of the cylinder head. The regulator maintains the fuel delivered to the injectors at a constant
pressure and returns excess fuel back to the fuel filter and pump via the fuel cooler.
A fuel filter is positioned on the chassis longitudinal, below the RH rear wheel arch. The fuel feed and return to and
from the engine passes through the filter. The filter also incorporates a water sensor, which illuminates a warning
lamp in the instrument pack.
A moulded fuel tank is located at the rear underside of the vehicle between the chassis longitudinals. The tank
provides the attachment for the fuel pump and the fuel gauge sender unit, which is located inside the tank.
Fuel Tank and Breather
The fuel tank and breather system is a major part of the fuel delivery system. The fuel tank and breathers are
located at the rear of the vehicle between the chassis longitudinals.
Fuel Tank
The moulded fuel tank is made from High Molecular Weight (HMW) High Density Polyethylene (HDPE), and is
manufactured using a proportion of recycled plastic.
The tank is held in position by a metal cradle which is secured to the chassis cross members by four bolts, two
holding the front of the cradle in position, two holding the rear. The fuel tank has a useable capacity of 75 litres
(16.5 gallons).
An aperture in the top surface of the tank allows for the fitment of the fuel pump and fuel gauge sender unit, which
is retained with a locking ring. A reflective metallic covering is attached to the tank with three scrivets to shield the
tank from heat generated by the exhaust system.
Fuel Tank Breather System
The fuel tank filler tube incorporates a tank vent which allows air and fuel vapour displaced from the tank when
filling to vent to atmosphere via the filler neck.
A breather spout within the tank controls the tank’Full’height. When fuel covers the spout it prevents fuel vapour
and air from escaping from the tank. This causes the fuel to’back-up’in the filler tube and shuts off the filler gun.
The position of the spout ensures that when the filler gun shuts off, a vapour space of approximately 10% of the
tanks total capacity remains. The vapour space ensures that the Roll Over Value (ROV) is always above the fuel
level and vapour can escape and allow the tank to breathe.
The ROV is welded to the top surface of the tank. It is connected by a tube to the filler tube, which in turn is
connected to the atmospheric vent pipe. The ROV allows fuel vapour to pass through it during normal vehicle
operation. In the event of the vehicle being overturned the valve shuts off, sealing the tank and preventing fuel
from spilling from the atmospheric vent pipe.
ProCarManuals.com

FUEL SYSTEM
9
DESCRIPTION AND OPERATION FUEL FILTER
1.Filter body
2.Nut
3.Bolt
4.Rubber washer
5.Water sensor6.Filter element
7.Air bleed valve
8.Air bleed connection
9.Copper washer
10.Connector
The fuel filter is mounted on the chassis longitudinal below the rear RH wheel arch. The filter has four quick
release coupling connections; low pressure feed from the fuel pump, low pressure return to the fuel pump, return
line from the fuel pressure regulator and a bleed line to the fuel pump. The fuel filter removes particulate matter
from the fuel and also separates water which accumulates at the bottom of the filter.
An air bleed valve is located in the bleed line connection. The valve comprises a restrictor and a membrane. The
restrictor has a small hole in its centre. This allows air and fuel to pass through the membrane. Air can pass
through the membrane, but once the membrane is wet with fuel, it will not allow further fuel to pass through.
The fuel filter has a replaceable screw-on cannister type filter element which is sealed to the filter body with rubber
seals. The lower part of the cannister has a screw connection for a water sensor. The filter has a flow rate of 180
litres/hour (47.6 US Gallons/hour).
ProCarManuals.com

COOLING SYSTEM
9
DESCRIPTION AND OPERATION Viscous Fan
1.Idler pulley drive attachment
2.Fan blades3.Bi-metallic coil
4.Body
The viscous fan provides a means of controlling the speed of the fan relative to the operating temperature of the
engine. The fan rotation draws air through the radiator, reducing engine coolant temperatures when the vehicle is
stationary or moving slowly.
The viscous fan is attached to an idler pulley at the front of the engine which is driven at crankshaft speed by the
auxiliary drive belt. The fan is secured to the pulley by a right hand threaded nut. The nut is positively attached to
the fan spindle which is supported on bearings in the fan body. The viscous drive comprises a circular drive plate
attached to the spindle and driven from the idler pulley. The drive plate and body have interlocking annular
grooves with a small clearance which provides the drive when silicone fluid enters the fluid chamber. A bi-metallic
coil is fitted externally on the forward face of the body. The coil is connected to and operates a valve in the body.
The valve operates on a valve plate with ports that connect the reservoir to the fluid chamber. The valve plate also
has return ports which, when the valve is closed, scoop fluid from the fluid chamber and push it into the reservoir
under centrifugal force.
Silicone fluid is retained in a reservoir at the front of the body. When the engine is off and the fan is stationary, the
silicone fluid level stabilises between the reservoir and the fluid chamber. This will result in the fan operating when
the engine is started, but the drive will be removed quickly after the fan starts rotating and the fan will’freewheel’.
ProCarManuals.com

26COOLING SYSTEM
10
DESCRIPTION AND OPERATION At low radiator temperatures, the fan operation is not required and the bi-metallic coil keeps the valve closed,
separating the silicone fluid from the drive plate. This allows the fan to’freewheel’reducing the load on the engine,
improving fuel consumption and reducing noise generated by the rotation of the fan.
When the radiator temperature increases, the bi-metallic coil reacts and moves the valve, allowing silicone fluid to
flow into the fluid chamber. The resistance to shear of the silicone fluid creates drag on the drive plate and
provides drive to the body and the fan blades.
ProCarManuals.com

26COOLING SYSTEM
12
DESCRIPTION AND OPERATION Viscous Fan Operation
A = Cold
B = Hot
1.Drive plate
2.Fan body
3.Clearance
4.Valve plate
5.Valve
6.Bi-metallic coil7.Fluid seals
8.Ball race
9.Fluid chamber
10.Reservoir
11.Return port
When the engine is off and the fan is not rotating, the silicone fluid stabilises within the fluid chamber and the
reservoir. The fluid levels equalise due to the return port in the valve plate being open between the fluid chamber
and the reservoir. In this condition, when the engine is started, silicone fluid is present in the fluid chamber and
causes drag to occur between the drive plate and the body. This causes the fan to operate initially when the
engine is started.
As the fan speed increases, centrifugal force and a scoop formed on the fluid chamber side of the valve plate,
pushes the silicone fluid through the return port in the valve plate into the reservoir. As the fluid chamber empties,
the drag between the drive plate and the body is reduced, causing the drive plate to slip. This reduces the
rotational speed of the fan and allows it to’freewheel’.
ProCarManuals.com