Jeep Liberty KJ. Manual — part 1391
INSTALLATION
UPPER RADIATOR HOSE - 2.8L DIESEL
1. Install upper radiator hose on radiator and thermostat housing.
2. Reposition hose clamps in proper position.
3. Refill cooling system to proper level (Refer to 7 - COOLING/ENGINE/COOLANT - STANDARD PROCEDURE).
HEATER CORE HOSES - 2.8L DIESEL
1. Connect heater core supply hose to heater core and viscous heater. Position hose clamps into proper position.
2. Connect heater core return hose to heater core and EGR cooler. Position hose clamps into proper position.
3. Install engine cover to engine (Refer to 9 - ENGINE COVER - INSTALLATION).
4. Refill cooling system to proper level (Refer to 7 - COOLING/ENGINE/COOLANT - STANDARD PROCEDURE).
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ENGINE
KJ
ENGINE BLOCK HEATER
DESCRIPTION
The block heater is operated by ordinary house current (110 Volt A.C.) through a power cord and connector located
in the engine compartment. The heater is mounted in a core hole (in place of a core hole plug) in the engine block,
with the heating element immersed in coolant.
CAUTION: The power cord must be secured in its retainer clips, and not positioned so it could contact
linkages or exhaust manifolds and become damaged.
OPERATION
The block heater element is submerged in the cooling system’s coolant. When electrical power (110 volt A.C.) is
applied to the element, it creates heat. This heat is transferred to the engine coolant. This provides easier engine
starting and faster warm-up when vehicle is operated in areas having extremely low temperatures.
REMOVAL - 3.7L
1. Drain cooling system (Refer to 7 - COOLING - STANDARD PROCEDURE).
2. Raise vehicle on hoist.
3. Detach power cord plug from heater.
4. Loosen screw in center of heater. Remove heater assembly.
INSTALLATION - 3.7L
1. Thoroughly clean core hole and heater seat.
2. Insert heater assembly (2) with element loop posi-
tioned upward .
3. With heater seated, tighten center screw securely
to assure a positive seal.
CAUTION: To prevent damage, the power cord
must be secured in it’s retaining clips, and not
positioned so it could contact linkages or exhaust
manifold.
4. Connect power cord to heater.
5. Lower vehicle.
6. Fill cooling system (Refer to 7 - COOLING - STAN-
DARD PROCEDURE).
KJ
ENGINE
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ENGINE COOLANT TEMPERATURE SENSOR
DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is used to sense engine coolant temperature. The sensor protrudes
into an engine water jacket.
The ECT sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as engine coolant temperature
increases, resistance (voltage) in the sensor decreases. As temperature decreases, resistance (voltage) in the sen-
sor increases.
OPERATION
At key-on, the Powertrain Control Module (PCM) sends out a regulated 5 volt signal to the ECT sensor. The PCM
then monitors the signal as it passes through the ECT sensor to the sensor ground (sensor return).
When the engine is cold, the PCM will operate in Open Loop cycle. It will demand slightly richer air-fuel mixtures
and higher idle speeds. This is done until normal operating temperatures are reached.
The PCM uses inputs from the ECT sensor for the following calculations:
•
for engine coolant temperature gauge operation through CCD or PCI (J1850) communications
•
Injector pulse-width
•
Spark-advance curves
•
ASD relay shut-down times
•
Idle Air Control (IAC) motor key-on steps
•
Pulse-width prime-shot during cranking
•
O2 sensor closed loop times
•
Purge solenoid on/off times
•
EGR solenoid on/off times (if equipped)
•
Leak Detection Pump operation (if equipped)
•
Radiator fan relay on/off times (if equipped)
•
Target idle speed
REMOVAL
3.7L ENGINE
The Engine Coolant Temperature (ECT) sensor (3) is
installed into a water jacket at front of intake manifold
near rear of generator.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR.
1. Partially drain cooling system.
2. Disconnect electrical connector from sensor.
3. Remove sensor from intake manifold.
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ENGINE
KJ
2.8L DIESEL ENGINE
WARNING: DO NOT REMOVE OR LOOSEN THE
COOLANT
PRESSURE/VENT
CAP,
CYLINDER
BLOCK DRAIN PLUGS, OR THE DRAINCOCK
WHEN THE SYSTEM IS HOT AND UNDER PRES-
SURE BECAUSE SERIOUS BURNS FROM THE
COOLANT CAN OCCUR.
1. Disconnect negative battery cable.
2. Drain the cooling system. (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE)
3. Disconnect coolant temperature sensor electrical
connector.
4. Remove coolant temperature sensor (3) from cylin-
der head.
INSTALLATION
3.7L ENGINE
1. Apply thread sealant to sensor threads.
2. Install sensor to engine.
3. Tighten coolant temperature sensor to 11 N·m (8 ft. lbs.) torque.
4. Replace any lost engine coolant.
2.8L DIESEL ENGINE
1. Install coolant temperature sensor in thermostat housing.
2. Connect coolant temperature sensor electrical connector.
3. Refill cooling system. (Refer to 7 - COOLING/ENGINE/COOLANT - STANDARD PROCEDURE)
4. Connect negative battery cable.
KJ
ENGINE
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