1996 LAND ROVER DEFENDER heater

COOLING SYSTEM
1
DESCRIPTION AND OPERATION ENGINE COOLING SYSTEM
Description
The complete cooling system of the 300Tdi engine
incorporates three independent functions:- Engine
(coolant) cooling; Turbo (charge air) intercooling;
Engine oil cooling.The intercooler is a separate aluminium unit, located
on the LH side of the engine compartment adjacent to
the radiator, sharing the same upper and lower
mountings. For details of turbo intercooling
See
FUEL SYSTEM, Description and operation,
Operation
. The oil cooler matrix is an integral part of
the radiator. Pre-formed pipes/hoses are used to link
the components within the separate systems as
shown below.
Engine cooling system
1.Radiator
2.Thermostat housing
3.Radiator bottom hose
4.Viscous fan
5.Water pump
6.Radiator top hose
7.Heater return hose
8.Coolant supply hose
9.By-pass hose
10.Radiator bleed (purge) hose
11.Bleed (purge) hose, thermostat housing
12.'Y' piece ejector
13.Expansion tank14.Heater rail
15.Heater unit
16.Heater feed hose
17.Intercooler
18.Air cleaner
19.Air feed hose
20.Turbocharger
21.Charge air supply pipe/hose
22.Cooled charge air supply hose
23.Exhaust manifold
24.Engine oil cooler
25.Feed pipe, engine oil cooler
26.Return pipe, engine oil cooler
27.Oil filter

26COOLING SYSTEM
2
DESCRIPTION AND OPERATION ENGINE (COOLANT) COOLING
Description
The 300Tdi engine uses a pressurised cooling system
and cross flow radiator which is supplied with coolant
from an expansion tank mounted on the RH side of
the engine compartment. A belt driven centrifugal
water pump, fitted to an auxiliary mounting assembly,pumps coolant to the engine crankcase, cylinder head
and vehicle heater unit.
An eleven bladed fan, incorporating a viscous
coupling, is driven by an independent pulley secured
to the front cover plate. The thermostat housing,
bolted to the front of the cylinder head, is fitted with a
vent valve that purges excessive air pressure and
coolant back to the expansion tank.
Engine coolant circulation (engine warm - thermostat open).
1.Radiator
2.Thermostat/housing
3.Radiator bottom hose
4.Viscous fan
5.Water pump
6.Radiator top hose
7.Heater return hose
8.Coolant supply hose9.By-pass hose
10.Radiator bleed (purge) hose
11.Thermostat housing bleed (purge) hose
12.'Y' piece ejector
13.Expansion tank
14.Heater rail
15.Heater unit
16.Heater feed hose

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
3
REPAIR WATER PUMP
Service repair no - 26.50.01
Remove
1.Disconnect battery.
2.Drain cooling system.
See Adjustment, Drain
and refill cooling system
3.Remove radiator top hose.
4.Remove intercooler top hose.
5.Slacken water pump and power steering pump
pulley retaining bolts.
6.Remove drive belt.
See ELECTRICAL, Repair,
Auxiliary drive belt
7.Unscrew flange nut and remove belt tensioner.
8.Remove oil filler cap and remove rocker cover
insulation.
9.Slacken retaining clip and disconnect hose at
heater rail.
10.Unscrew 3 bolts and remove water pump pulley.
11.Unscrew 3 bolts and remove power steering
pump pulley.
12.Remove 8 bolts securing water pump, noting
location of 3 through bolts into cylinder block.
13.Withdraw pump and gasket from auxiliary
mounting bracket.
14.Clean all gasket material from mating faces.
Refit
15.Using new gasket, fit water pump to mounting
bracket. Tighten bolts to
25 Nm (18 lbf/ft).
16.Fit power steering pump pulley.
17.Fit water pump pulley. Tighten bolts of both
pulleys to
25 Nm (18 lbf/ft).
18.Fit drive belt.See ELECTRICAL, Repair,
Auxiliary drive belt
19.Fit hose at heater rail.
20.Fit rocker cover insulation and oil filler cap.
21.Fit drive belt tensioner. Tighten retaining nut to
45 Nm (33 lbf/ft).
22.Fit intercooler top hose.
23.Fit radiator top hose.
24.Refill cooling system.
See Adjustment, Drain
and refill cooling system
25.Reconnect battery.

26COOLING SYSTEM
4
REPAIRREV: 05/99 AUXILIARY MOUNTING BRACKET AND GASKET
Service repair no - 26.50.04
Remove
1.Disconnect battery.
2.Drain cooling system
See Adjustment, Drain
and refill cooling system
.
3.Remove radiator top hose.
4.Remove intercooler top hose.
5.Remove viscous fan unit.
See Viscous
coupling and fan
6.Remove fan cowl.See Fan cowl
7.Slacken power steering pump pulley retaining
bolts.
8.Remove drive belt.
See ELECTRICAL, Repair,
Auxiliary Drive belt
9.Unscrew 3 bolts and remove power steering
pump pulley.
10.Remove 4 bolts securing power steering pump
mounting bracket.
11.Lower pump and bracket. Do not disconnect fluid
pipes.
12.Remove generator.
See ELECTRICAL, Repair,
Generator
13.Unscrew retaining nut and remove drive belt
tensioner.
14.Release hose clip from bracket above water
pump.15.Disconnect bottom hose/heater return hose at
water pump and heater rail.
16.Disconnect by-pass hose from water pump and
thermostat housing.
17.Remove 5 bolts (one with nut) and single
retaining nut, securing auxiliary mounting
bracket to cylinder block.
18.Withdraw mounting bracket, complete with water
pump.
19.Remove gasket and clean mating faces.
Refit
20.Using 2 slave studs, fit new gasket.
NOTE: All fixing bolts and nuts should be
tightened to
25 Nm (18 lbf/ft)unless
otherwise stated.
21.Locate mounting bracket, complete with water
pump on slave studs and secure with 4 other
fixings.
22.Remove slave studs and fit remaining bolts/nuts.
23.Fit by-pass hose to thermostat housing and
water pump.
24.Fit bottom hose/heater return hose to water
pump and heater rail.
25.Fit heater hose clip to mounting bracket.
26.Fit drive belt tensioner. Tighten nut to
45 Nm (33
lbf/ft).
27.Fit generator.See ELECTRICAL, Repair,
Generator
Do not fit drive belt at this stage.

MANIFOLD AND EXHAUST SYSTEM
1
REPAIR INDUCTION MANIFOLD
Service repair no - 30.15.02
Remove
1.Disconnect battery.
2.Remove oil filler cap and remove rocker cover
insulation.
3.Remove hose intercooler to induction manifold. If
fitted, remove EGR valve.
See FUEL SYSTEM,
Repair, EGR valve
4.Remove 2 screws and release heat shield from
induction manifold.
5.Slacken induction manifold lower securing nuts,
located below exhaust manifold.
6.Remove induction manifold upper securing bolts.
7.Remove induction manifold. Plug apertures in
cylinder head with clean rag to prevent any items
falling into engine.
8.Check gasket is satisfactory for further use.
Refit
9.Clean induction manifold mating face.
10.Position induction manifold and secure with
upper and lower fixings.
11.Tighten securing nuts and bolts to
25 Nm (18
lbf/ft).
12.Fit manifold heat shield.
13.Fit hose intercooler to induction manifold.
14.Fit rocker cover insulation.
15.Reconnect battery.INDUCTION/EXHAUST MANIFOLD GASKET
Service repair no - 30.15.15
Remove
1.Remove induction manifold
See Induction
manifold
.
2.Remove turbocharger outlet hose.
3.Raise vehicle and slacken exhaust front pipe to
intermediate silencer flange nuts. Ensure pipe is
free to turn.
NOTE: If removing exhaust manifold and
turbocharger assembly from vehicle,
remove manifold to exhaust front pipe
nuts while working under vehicle.
4.Remove exhaust manifold securing nuts,
removing centre lower nut first.
5.Move heater rail clear of exhaust manifold.
6.With exhaust manifold and turbocharger still
attached to exhaust front pipe, withdraw from
head by turning front pipe until sufficient access
is gained to remove gasket.
7.Suitably support exhaust manifold and
turbocharger assembly to prevent damage.
8.Remove induction manifold lower nuts.
9.Remove gasket.
10.Clean mating faces.

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
.

76CHASSIS AND BODY
34
REPAIRREV: 05/99 LOWER FASCIA PANEL (HEATER DUCT)
ASSEMBLY
Service repair no - 76.46.05
Remove
1.Disconnect battery.
2.Remove steering wheel
See STEERING,
Repair, Steering wheel
.
3.Remove steering column nacelle
See
STEERING, Repair, Steering column nacelle
.
4.Remove instrument panel
See INSTRUMENTS,
Repair, instrument panel
.
5.Release heater cable at control lever
See
HEATING AND VENTILATION, Repair, Heater
control cable - air distribution
.
6.Remove 2 screws, withdraw switch panel from
lower fascia and disconnect switch multi-plugs.
7.Prise out Land Rover decal and remove screw
securing grab handle to crash pad.
8.Remove lower screw and lift grab handle from
lower fascia panel.
9.On RH drive vehicles only, remove screw
securing LH side of finisher to wiper motor cover.
10.Remove 4 screws and remove both demister
vents from crash pad.
11.Remove 3 screws securing crash pad to fascia
bulkhead.
12.Remove crash pad.
13.Remove radio, if fitted.
14.Remove 2 trim studs securing radio housing to
trim panel. Remove radio housing.