COOLING SYSTEM
7
DESCRIPTION AND OPERATION Radiator
The 44 row radiator is located at the front of the vehicle in the engine compartment. The cross flow type radiator is
manufactured from aluminium with moulded plastic end tanks interconnected with tubes. The bottom four rows are
separate from the upper radiator and form the lower radiator for the fuel cooler. Aluminium fins are located
between the tubes and conduct heat from the hot coolant flowing through the tubes, reducing the coolant
temperature as it flows through the radiator. Air intake from the front of the vehicle when moving carries the heat
away from the fins. When the vehicle is stationary, the viscous fan draws air through the radiator fins to prevent
the engine from overheating.
Two connections at the top of the radiator provide for the attachment of the top hose from the outlet housing and
bleed pipe to the expansion tank. Three connections at the bottom of the radiator allow for the attachment of the
bottom hose to the thermostat housing and the return hose from the oil cooler and the feed hose to the fuel cooler.
The bottom four rows of the lower radiator are dedicated to the fuel cooler. The upper of the two connections at
the bottom of the radiator receives coolant from the oil cooler. This is fed through the four rows of the lower
radiator in a dual pass and emerges at the lower connection. The dual pass lowers the coolant temperature by up
to 24°C before being passed to the fuel cooler. Two smaller radiators are located in front of the cooling radiator.
The upper radiator is the intercooler for the air intake system and the lower radiator provides cooling of the
gearbox oil.
Pipes and Hoses
The coolant circuit comprises flexible hoses and metal formed pipes which direct the coolant into and out of the
engine, radiator and heater matrix. Plastic pipes are used for the bleed and overflow pipes to the expansion tank.
A bleed screw is installed in the radiator top hose and is used to bleed air during system filling. A drain plug to
drain the heater and cylinder block circuit of coolant is located on the underside of the coolant pump feed pipe.
Oil Cooler
The oil cooler is located on the left hand side of the engine block behind the oil centrifuge and oil filter. Oil from the
oil pump is passed through a heat exchanger which is surrounded by coolant in a housing on the side of the
engine.
Full water pump flow is directed along the cooler housing which also distributes the flow evenly along the block
into three core holes for cylinder cooling. This cools the engine oil before it is passed into the engine. A small
percentage of the coolant from the oil cooler passes into a metal pipe behind the engine. It then flows into the
lower radiator via a hose.
Fuel Cooler
The fuel cooler is located on the right hand side of the engine and is attached to the inlet manifold. The cooler is
cylindrical in design and has a coolant feed connection at its forward end. A’T’connection at the rear of the cooler
provides a connection for the coolant return from the heater matrix and coolant return from the fuel cooler.
The’T’connection houses a thermostat which opens at approximately 82°C. This prevents the cooler operating in
cold climates. Two quick release couplings on the cooler allow for the connection of the fuel feed from the
pressure regulator and return to the fuel tank. A counter flow system is used within the cooler.
Fuel flows around a coolant jacket within the cooler and flows from the back to the front of the cooler. As the hot
fuel cools travelling slowly forwards it meets progressively colder coolant travelling in the opposite direction
maintaining a differential cooling effect.
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86ELECTRICAL
12
DESCRIPTION AND OPERATION IMMOBILISATION SYSTEM - FROM 02MY
Engine immobilisation is available on all 2002MY engine derivatives, although it is not available in selected
markets. On Td5 models, the immobilisation system is controlled directly by the anti-theft alarm ECU. On 300Tdi
models, the immobilisation system is controlled by an engine immobilisation ECU in conjunction with the anti-theft
alarm ECU.
When immobilisation occurs on Td5 models, engine crank is disabled by the anti-theft alarm ECU breaking the
earth path for the starter relay coil and the ECM disables the fuel pump relay and the glow plug relay.
When immobilisation occurs on 300Tdi models, engine crank is disabled by the anti-theft alarm ECU breaking the
earth path for the starter relay coil and the engine immobilisation ECU disables the fuel cut-off solenoid, the starter
motor solenoid and the glow plug relay.
Two types of immobilisation are available; passive and active.
Engine Immobilised Warning Lamp
The engine immobilised warning lamp is located in the instrument pack. The lamp is used by the anti-theft alarm
ECU to show that the engine is immobilised during an attempted engine start.
The warning lamp receives a battery supply from the ignition switch position I (aux) via the passenger
compartment fusebox. The anti-theft alarm ECU controls the warning lamp. When the warning lamp is not
required, the ECU supplies a battery supply to the warning lamp. When warning lamp operation is required, the
ECU provides an earth for the bulb.
If the ignition switch is moved to the crank position, but operation of the starter motor is prohibited and the engine
immobilised warning lamp flashes, then the anti-theft alarm ECU has not received the correct code from the
remote handset and the vehicle will remain immobilised. Ensure that the remote handset is in the proximity of the
transponder coil. If the remote handset is not available or inoperative, the immobilisation system can be disarmed
using the EKA procedure outlined later in this section.
If the ignition switch is turned to the crank position III and the remote handset is not in the proximity of the
transponder coil, engine immobilisation will remain active and the warning lamp will flash to inform the driver.
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