Freelander System Description and Operation
COOLING SYSTEM - K SERIES KV6
26-3-6
DESCRIPTION AND OPERATION
Description
General
The engine cooling system maintains the engine within the optimum operating temperature range under varying
ambient temperature and engine load conditions. In addition, the system cools the engine oil, the Intermediate
Reduction Drive (IRD) and the transmission fluid, and provides the heat source for passenger compartment heating.
The system consists of:
l
A coolant pump.
l
A radiator.
l
A Pressure Relief Thermostat (PRT).
l
An expansion tank.
l
Interconnecting hoses and coolant rail.
l
Two cooling fans
l
Heater diverter valve (From 2003 Model Year)
Engine oil and transmission fluid are cooled by plate type heat exchangers. The engine oil cooler is attached to the
sump at the front of the engine. The transmission oil cooler is attached to the front of the gearbox. The IRD is cooled
by an internal plate type heat exchanger incorporated into the IRD lubrication circuit.
Coolant Pump
The rotor type coolant pump is integrated into the front of the engine, between the cylinder blocks. The pump is driven
by the camshaft timing belt via a plain pulley installed on the pump rotor shaft. The pulley also acts as an idler pulley
for the camshaft timing belt.
Radiator
The radiator is a cross flow type with an aluminium matrix and moulded plastic end tanks. The bottom of the radiator
is located in rubber bushes on the front lower crossmember. The top of the radiator is secured to the bonnet locking
platform by threaded retainers. The top hose connects the radiator to a coolant outlet elbow in the cylinder block. The
bottom hose connects the radiator to the thermostat housing.
Pressure Relief Thermostat (PRT)
The PRT is installed in a housing located in a coolant outlet port in the cylinder block, between the cylinder banks.
The thermostat housing incorporates inlet connections for the bottom hose and the return hose from the IRD cooler/
heater/ transmission cooler. A pipe connects the outlet side of the thermostat housing to the coolant pump inlet.
The thermostat is located in the inlet side of the cooling circuit, which provides a more stable control of the coolant
temperature in the engine. The housing contains a wax element and a spring loaded by-pass flow valve. The PRT
senses all parameters such as engine speed, engine heat input and ambient temperature and reacts according to the
actual operating conditions of the engine.
The wax element thermostat is used to maintain the coolant at the optimum temperature for efficient combustion and
assist engine warm-up. The thermostat is closed at low coolant temperatures with the flow being controlled by the by-
pass valve. When the coolant temperature reaches approximately 88
°
C (190
°
F), the thermostat begins to open and
is fully open at approximately 102
°
C (216
°
F).