low oil pressure LAND ROVER DEFENDER 1996 Workshop Manual

GENERAL SPECIFICATION DATA
3
INFORMATION FUEL SYSTEM
Fuel lift pump type Mechanical with hand primer............................................................
Fuel lift pump pressure 42 - 55 Kgf/cm
2(3 - 4 lbf/in2) at 1800 rpm .....................................................
Fuel filter Paper element in disposable canister..........................................................................
Air cleaner Paper element type........................................................................
COOLING SYSTEM
System type Pressurised, spill return, thermostatically controlled.....................................................................
water and anti freeze mixture. Pump assisted thermo
syphon. Coolant radiator combined with oil cooler and
turbo intercooler.
Cooling fan 11 blade axial flow 433 mm diameter, 1.29:1 drive.......................................................................
ratio, with viscous coupling.
Pump type Centrifugal, impellor, belt driven........................................................................
Thermostat opening 88°C .........................................................
Expansion tank cap pressure 1,06 Kgf/cm
2(15 Ibf/in2) (system pressure) ...........................................
CLUTCH
Type Valeo diaphragm spring.................................................................................
Centre plate diameter 235 mm.......................................................
Facing material Verto F202 grooved.................................................................
Release bearing Ball journal...............................................................
TRANSMISSION
Main gearbox
Type R380 Single helical constant mesh.......................................................................
Speeds 5 forward, 1 reverse, all synchromesh.............................................................................
Transfer box
Type LT230 Two speed reduction on main gearbox output. Front......................................................................
and rear drive permanently engaged via a lockable
differential
Rear axle
Type Spiral bevel, fully floating shafts.................................................................................
Ratio 3.54:1.................................................................................

GENERAL FITTING REMINDERS
5
INFORMATION JOINTS AND JOINT FACES
1.Always use correct gaskets where they are
specified.
2.Use jointing compound only when
recommended. Otherwise fit joints dry.
3.When jointing compound is used, apply in a thin
uniform film to metal surfaces; take great care to
prevent it from entering oilways, pipes or blind
tapped holes.
4.Remove all traces of old jointing materials prior
to reassembly. Do not use a tool which could
damage joint faces.
5.Inspect joint faces for scratches or burrs and
remove with a fine file or oil stone; do not allow
removed material or dirt to enter tapped holes or
enclosed parts.
6.Blow out any pipes, channels or crevices with
compressed air, fit new 'O' rings or seals
displaced by air blast.FLEXIBLE HYDRAULIC PIPES, HOSES
1.Before removing any brake or power steering
hose, clean end fittings and area surrounding
them as thoroughly as possible.
2.Obtain appropriate plugs or caps before
detaching hose end fittings, so that ports can be
immediately covered to exclude dirt.
3.Clean hose externally and blow through with
airline. Examine carefully for cracks, separation
of plies, security of end fittings and external
damage. Reject any hose found faulty.
4.When refitting hose, ensure that no unnecessary
bends are introduced, and that hose is not
twisted before or during tightening of union nuts.
5.Containers for hydraulic fluid must be kept
absolutely clean.
6.Do not store brake fluid in an unsealed
container. It will absorb water, and fluid in this
condition would be dangerous to use due to a
lowering of its boiling point.
7.Do not allow brake fluid to be contaminated with
mineral oil, or use a container which has
previously contained mineral oil.
8.Do not re-use brake fluid bled from system.
9.Always use clean brake fluid to clean hydraulic
components.
10.Fit a cap to seal a hydraulic union and a plug to
its socket after removal to prevent ingress of dirt.
11.Absolute cleanliness must be observed with
hydraulic components at all times.
12.After any work on hydraulic systems, inspect
carefully for leaks underneath the vehicle while a
second operator applies maximum pressure to
the brakes (engine running) and operates the
steering.

12ENGINE
2
REPAIR ENGINE OIL PRESSURE TEST
Service repair no - 12.90.09/01
WARNING: Use suitable exhaust
extraction equipment if an engine test is
being carried out in a workshop.
WARNING: If vehicle has been running,
engine wil be hot; care must be taken
when fitting test equipment to prevent
personal injury.
1.Check that engine lubricant is to correct level.
2.Remove oil pressure switch .
3.Connect pressure test gaugeLRT-12-052A,as
shown.
4.Start and run engine to normal operating
temperature.
5.With engine running at idle check oil pressure,
which should read 1.76 bar (25.87 lbf/in
2).6.If pressure is low it can be caused by the
following:-
Thin or diluted oil.
Low oil in sump.
Choked oil strainer.
Faulty oil pressure relief valve.
Excessively worn or damaged oil pump
displacement gears.
Excessive crankshaft bearing clearance.
7.If excessive pressure is indicated it can be
caused by :-
Overfilling engine with lubricant.
Sticking oil pressure relief valve.
Blockage in breather system.

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.

30MANIFOLD AND EXHAUST SYSTEM
2
REPAIR Refit
11.Fit new gasket over manifold studs.
12.Loosely fit induction manifold lower nuts to
studs.
13.Fit exhaust manifold and secure with central
upper and lower nuts.
14.Locate heater rail to its correct position and
secure with outer exhaust manifold nuts.
15.Tighten all exhaust manifold nuts to
45 Nm (33
lbf/ft).
16.Tighten exhaust front pipe to intermediate
silencer nuts to
50 Nm (37 lbf/ft).
17.Fit turbocharger outlet pipe.
18.Fit induction manifold
See Induction manifold
.EXHAUST MANIFOLD/TURBOCHARGER
ASSEMBLY
Service repair no - 30.15.10
Remove
1.Remove induction manifold
See Induction
manifold
.
2.Disconnect turbocharger inlet hose.
3.Disconnect boost pressure pipe at turbocharger.
4.Remove intercooler bottom hose.
5.Place suitable container under engine and
disconnect turbocharger oil feed and return
pipes at cylinder block.
6.Remove 3 nuts securing exhaust front pipe to
manifold flange.
7.Remove 7 nuts and lift exhaust manifold and
turbocharger assembly from cylinder head.
8.Discard manifold gasket.
Refit
9.Fit new manifold gasket.
10.Position exhaust manifold assembly onto
location studs and secure to cylinder head.
Tighten nuts to
45 Nm (33 lbf/ft).
11.Secure exhaust front pipe to manifold flange.
Tighten fixings to
50 Nm (37 lbf/ft).
12.Reconnect turbocharger oil feed and return
pipes at cylinder block.
13.Fit intercooler bottom hose.
14.Fit boost pressure pipe at turbocharger.
15.Fit turbocharger inlet hose.
16.Fit induction manifold
See Induction manifold
.

CLUTCH
1
FAULT DIAGNOSIS CLUTCH ASSEMBLY CONDITIONS
For the clutch to operate correctly it is important the
following conditions are satisfied:-
·The primary shaft (15) must be free in the
crankshaft spigot bush (17).
·The friction plate (2) must be able to slide easily on
the splines on the primary shaft (15), to a position
where it does not contact either the flywheel or the
pressure plate.
·The friction plate must not be distorted or the
linings contaminated with oil, which may cause it to
stick or continue to run in contact with the flywheel
or pressure plate.
A number of faults can develop in the operation of the
clutch for a variety of reasons and most faults are due
to normal wear at high mileage. Problems can also
occur if the unit has been renewed by an unskilled
operator.
Recognising and diagnosing a particular clutch fault is
therefore of paramount importance in ensuring that
the problem is rectified at the first attempt.
Problems which develop in the clutch are as follows:-
·Clutch spin/drag
·Clutch slip
·Clutch judder/fierceCLUTCH SPIN - DRAG
Symptoms
Clutch spin is that, with engine running and clutch
pedal depressed, the gears cannot be immediately
engaged without making a grinding noise. This
indicates the clutch is not making a clean break.
However, if the clutch pedal is held depressed for
several seconds the friction plate will eventually break
free from the engine and the gear will engage silently.
Clutch spin as it becomes more severe develops into
clutch drag, making the silent engagement of a gear
impossible, regardless of how long the pedal is held
depressed.
CLUTCH SLIP
Symptoms
Clutch slip is most evident climbing a hill or when the
vehicle is moving off from stationary with a heavy
load. As the clutch is released, slip occurs between
the engine and the transmission, allowing the engine
speed to increase without a corresponding increase in
vehicle speed.
Clutch slip can develop to the stage where no power
is transmitted through the clutch as the pedal is
released.
CLUTCH JUDDER - FIERCE
Symptoms
Clutch judder or fierce engagement, like slip, is most
likely to occur when the vehicle is moving off from
stationary. As the clutch pedal is released the vehicle
will move rapidly or in a series of jerks, which cannot
be controlled even by careful operation of the clutch
by the driver.
It should be noted that a vehicle may display all the
symptoms or any combination of the symptoms
described, depending on the driving conditions vehicle
load and operating temperatures.

33CLUTCH
2
OVERHAUL
18.Place coil spring over valve stem.
19.Insert retainer into spring.
20.Compress spring and engage valve stem in
keyhole slot in retainer.
21.Fit seal, large diameter last, to piston.
22.Insert piston into spring retainer and engage
locking prong.
23.Smear piston with suitable rubber grease and
insert assembly, valve end first, into cylinder.
24.Fit push-rod, retaining washer and circlip.
25.Fit clutch master cylinder to vehicle
See Repair,
Master cylinder
.SLAVE CYLINDER - OVERHAUL
Service repair no - 33.35.07
Dismantle
1.Remove slave cylinder
See Repair, Slave
cylinder
.
2.Withdraw dust cover.
3.Expel piston assembly, applying low pressure air
to fluid inlet.
4.Withdraw spring.
5.Remove seal from piston.
6.Remove bleed valve.
Inspection
7.Clean all components with new hydraulic fluid
fluid and allow to dry.
8.Examine cylinder bore and piston, ensure that
they are smooth to touch with no corrosion,
score marks or ridges. If there is any doubt, fit
new components.
9.Renew seal and dust cover from slave cylinder
overhaul kit.

MANUAL GEARBOX
1
DESCRIPTION AND OPERATION R380 GEARBOX
Description
The all synchromesh five speed manual gearbox unit,
is married to a two speed transfer gearbox.
All the gears, including reverse, run on needle roller
bearings and the main, layshaft and primary shafts
are supported by tapered roller bearings.The whole of the geartrain is lubricated through
drillings in the shafts, supplied by a low pressure
pump driven from the rear of the layshaft. The gear
change has a single rail selector and spool type
interlock. The main and transfer gearboxes ventilate
through nylon pipes, which terminate high up in the
engine compartment to prevent water entry when the
vehicle is operating in adverse conditions.
R380 Gearbox Components
1.Mainshaft 1st gear
2.Mainshaft 2nd gear
3.Mainshaft 3rd gear
4.Primary input shaft/4th gear
5.Mainshaft 5th gear
6.Layshaft
7.Mainshaft
8.Lubrication pump
9.Oil filter10.Ventilation pipe
11.Single rail gear shift
12.1st/2nd synchromesh
13.Oil seals
14.3rd/4th synchromesh
15.5th/reverse gear synchromesh
16.Selective spacers (mainshaft/layshaft end float)
17.Selective spacer (5th gear/reverse hub)

REAR AXLE AND FINAL DRIVE
1
FAULT DIAGNOSIS FAULT DIAGNOSIS
Complaint - Oil leaks
An external leak of lubrication from the hub seals can
be caused by a faulty internal seal. For example, if the
seals which separate the differential from the hubs are
faulty and the vehicle is operating or parked on an
embankment, oil from the differential may flood one
hub resulting in a lack of lubrication in the differential.
When a seal is found to be leaking check the axle
ventilation system, as a blockage can cause internal
pressure to force oil past the seals.
See 'Description and Operation' for illustrations of oil
seal locations.
When investigating hub seal leaks check the grease
for dilution with oil. Also check the differential oil level,
for signs of metal particles in the oil and the condition
of internal seals.
If the vehicle is driven in deep water with defective oil
seals, water may contaminate the lubricants and raise
the differential oil level, giving a false impression that
the housing has been overfilled.
Do not assume that a high oil level in the
differential is due to over filling or, that a low level
is because of an external leak.

FRONT AXLE AND FINAL DRIVE
1
FAULT DIAGNOSIS FAULT DIAGNOSIS
Complaint - Oil leaks
An external leak of lubrication can be caused by a
faulty internal seal. For example, if the seals which
separate the differential from the swivel housings are
faulty and the vehicle is operating or parked on an
embankment, oil may leak across the axle leaving one
swivel with a high level and the opposite swivel and
differential lacking lubrication.
See 'Description and Operation' for illustrations of oil
seal locations.
When investigating leaks or checking oil levels, it is
essential that all the lubrication is drained from any
housing with a high level and that the other levels are
checked.
Swivel oil should be checked for signs of grease
leaking from the hub bearings and oil contamination of
the hub grease.
Check that the axle ventilation system is clear, as a
blockage can cause internal pressure to force oil past
the seals.
If the vehicle is driven in deep water with defective oil
seals, water may contaminate the lubricants and when
checked, give a false impression that the housing has
been overfilled with oil.
Do not assume that a high oil level is due to over
filling or, that a low level is because of an external
leak.