Range Rover P38
26
COOLING SYSTEM
NEW RANGE ROVER
4
DESCRIPTION AND OPERATION
ECT sensor and temperature gauge sender unit -
up to 99MY
An Engine Coolant Temperature (ECT) sensor and a
temperature gauge sender unit are located on the inlet
manifold adjacent to the outlet pipe. The ECT sensor
monitors coolant temperature emerging from the
engine and sends signals relating to coolant
temperature to the ECM for engine management. The
temperature gauge sender unit operates the warning
lamp and temperature gauge in the instrument pack.
See FUEL SYSTEM - Engine Management,
Description and operation.
ECT sensor - from 99MY
An Engine Coolant Temperature (ECT) sensor is
located on the inlet manifold adjacent to the outlet
pipe. The ECT sensor monitors coolant temperature
emerging from the engine and sends signals relating
to coolant temperature to the ECM for engine
management and to the instrument pack for
temperature gauge operation.
See FUEL SYSTEM -
Engine Management, Description and operation.
Expansion tank
The expansion tank is located in the engine
compartment and attached to the right hand inner
wing. The tank is made from moulded plastic and has
a maximum coolant level when cold mark moulded on
the side.
Excess coolant created by heat expansion is returned
to the expansion tank from the bleed pipe at the top of
the radiator. An outlet pipe is connected into the
thermostat housing and replaces coolant displaced by
heat expansion into the system when the engine is
cool.
The tank is fitted with a sealed pressure cap. The cap
contains a pressure relief valve which opens to allow
excessive pressure and coolant to vent through the
overflow pipe. The relief valve opens at a pressure of
1.4 bar (20 lbf.in) and above.
Heater matrix
The heater matrix is fitted in the distribution unit of the
heating and ventilation system inside the passenger
compartment. Two pipes pass through the bulkhead
and provide coolant flow to and from the matrix.
The matrix is constructed from aluminium with two
end tanks interconnected with tubes. Aluminium fins
are located between the tubes and conduct heat away
from the hot coolant flowing through the tubes. Air
from the heater assembly is warmed as it passes
through the matrix fins. The warm air is then
distributed into the passenger compartment as
required.
See HEATING AND VENTILATION,
Description and operation.
Radiator
The radiator is located at the front of the vehicle. The
vertical flow radiator is manufactured from aluminium
with moulded plastic tanks at the top and bottom,
interconnected with tubes. Aluminium fins are located
between the tubes and conduct heat from the hot
coolant flowing through the tubes, reducing the
coolant temperature as it passes through the radiator.
Air intake from the front of the vehicle when moving
carries heat away from the fins. When the vehicle is
stationary, the viscous fan draws air through the fins
to prevent the engine from overheating.
Two connections at the top of the radiator provide for
the attachment of the top hose and bleed pipe. A
connection at the bottom of the radiator allows for the
attachment of the bottom hose to the thermostat
housing.
Two coolers are located in front of the cooling
radiator. The upper cooler provides cooling of the
engine oil and the lower cooler provides cooling for
the gearbox oil.
See MANUAL GEARBOX, Description and
operation.
See AUTOMATIC GEARBOX, Description and
operation.
See ENGINE, Description and operation.
Pipes and hoses
The coolant circuit comprises flexible hoses and metal
formed pipes which direct 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 drain plug is fitted to each cylinder bank in the
cylinder block. These are used to drain the block of
coolant.
