2002 JEEP LIBERTY engine block

LUBRICATION
DESCRIPTION
The lubrication system is a full-flow filtration,
pressure feed type. The oil pump is mounted in the
front engine cover and driven by the crankshaft.
OPERATION
Engine oil drawn up through the pickup tube and
is pressurized by the oil pump and routed through
the full-flow filter to the main oil gallery running the
length of the cylinder block. A diagonal hole in each
bulkhead feeds oil to each main bearing. Drilled pas-
sages within the crankshaft route oil from main bear-
ing journals to connecting rod journals. Balance shaft
lubrication is provided through an oil passage from
the number one main bearing cap through the bal-
ance shaft carrier support leg. This passage directly
supplies oil to the front bearings and internal
machined passages in the shafts that routes oil from
front to the rear shaft bearing journals. A vertical
hole at the number five bulkhead routes pressurized
oil through a restrictor (integral to the cylinder head
gasket) up past a cylinder head bolt to an oil gallery
running the length of the cylinder head. The cam-
shaft journals are partially slotted to allow a prede-
termined amount of pressurized oil to pass into the
bearing cap cavities. Lubrication of the camshaft
lobes are provided by small holes in the camshaft
bearing caps that are directed towards each lobe. Oil
returning to the pan from pressurized components
supplies lubrication to the valve stems. Cylinder
bores and wrist pins are splash lubricated from
directed slots on the connecting rod thrust collars.
DIAGNOSIS AND TESTING - ENGINE OIL
PRESSURE CHECKING
(1) Disconnect and remove oil pressure switch.
(Refer to 9 - ENGINE/LUBRICATION/OIL PRES-
SURE SENSOR/SWITCH - REMOVAL)
(2) Install Special Tools C-3292 Gauge with 8406
Adaptor fitting.
(3) Start engine and record oil pressure. Refer to
Specifications for correct oil pressure requirements.
(Refer to 9 - ENGINE - SPECIFICATIONS)
CAUTION: If oil pressure is 0 at idle, do not perform
the 3000 RPM test
(4) If oil pressure is 0 at idle. Shut off engine,
check for pressure relief valve stuck open, a clogged
oil pick-up screen or a damaged oil pick-up tube
O-ring.
(5) After test is complete, remove test gauge and
fitting.
Fig. 76 TRANSMISSION MOUNT 3.7L 2WD AUTO
TRANS
1 - BOLT
2 - MOUNT
Fig. 77 TRANSMISSION MOUNT 3.7L 4WD AUTO
TRANS
1 - MOUNT
2 - BOLT
9s - 46 ENGINEKJ
LUBRICATION (Continued)

(3) Screw oil filter on until the gasket contacts
base. Tighten to 21 N´m (15 ft. lbs.).
OIL PAN
REMOVAL
(1) Remove air cleaner assembly.
(2) Raise vehicle on hoist and drain engine oil.
(3) Loosen the engine mount thru bolts.
(4) Disconnect exhaust pipe at manifold.
(5) Remove structural collar, if equipped.
(6) Remove front axle mounting bolts, and lower
axle as far possible, if equipped.
(7) Using suitable jack, raise engine as needed.
(8) Remove oil pan attaching bolts.
(9) Remove oil pan.
(10) Clean oil pan and all gasket surfaces.
INSTALLATION
(1) Install the oil pan gasket to the block.
(2) Apply a 3MM (1/8 inch) bead of MopartEngine
RTV at the oil pump to engine block parting line
(Fig. 80).
(3) Install pan and tighten the screws to 12 N´m
(105 in. lbs.).
(4) Lower engine, and remove jack.
(5) Tighten engine mount thru bolts.
(6) Raise the front axle into position, and reinstall
front axle mounting bolts. If equipped.
(7) Reconnect exhaust pipe to manifold.
(8) Install structural collar, if equipped.
(9) Lower vehicle.(10) Fill engine crankcase with proper oil to cor-
rect level.
(11) Reinstall air cleaner assembly.
OIL PRESSURE SENSOR/
SWITCH
DESCRIPTION
The 3±wire, electrical/mechanical engine oil pres-
sure sensor (sending unit) is located in an engine oil
pressure gallery.
OPERATION
The oil pressure sensor uses three circuits. They
are:
²A 5±volt power supply from the Powertrain Con-
trol Module (PCM)
²A sensor ground through the PCM's sensor
return
²A signal to the PCM relating to engine oil pres-
sure
The oil pressure sensor has a 3±wire electrical
function very much like the Manifold Absolute Pres-
sure (MAP) sensor. Meaning different pressures
relate to different output voltages.
A 5±volt supply is sent to the sensor from the PCM
to power up the sensor. The sensor returns a voltage
signal back to the PCM relating to engine oil pres-
sure. This signal is then transferred (bussed) to the
Fig. 79 2.4 OIL FILTERFig. 80 OIL PAN GASKET INSTALLATION
1 - SEALER LOCATION
9s - 48 ENGINEKJ
OIL FILTER (Continued)

INSPECTION
(1) Inspect the mating surface of the oil pump.
Surface should be smooth. Replace pump cover if
scratched or grooved.
(2) Lay a straightedge across the pump cover sur-
face (Fig. 84). If a 0.025 mm (0.001 in.) feeler gauge
can be inserted between cover and straight edge,
cover should be replaced.
(3) Measure thickness and diameter of outer rotor.
If outer rotor thickness measures 9.40 mm (0.370 in.)
or less (Fig. 85), or if the diameter is 79.95 mm
(3.148 in.) or less, replace outer rotor.
(4) If inner rotor measures 9.40 mm (0.370 in.) or
less replace inner rotor (Fig. 86).
ASSEMBLY
(1) Assemble pump, using new parts as required.
Install the inner rotor with chamfer facing the
cast iron oil pump cover.
(2) Prime oil pump before installation by filling
rotor cavity with engine oil.
(3) Install cover and tighten fasteners to 12 N´m
(105 in. lbs.).
CAUTION: Oil pump pressure relief valve must be
installed correctly or serious engine damage may
occur.
(4) Install relief valve, spring, gasket and cap.
Tighten cap to 41 N´m (30 ft. lbs.).
INSTALLATION
(1) Make sure all surfaces are clean and free of oil
and dirt.
(2) Apply MopartGasket Maker to oil pump as
shown in (Fig. 87). Install O-ring into oil pump body
discharge passage.
(3) Prime oil pump with engine oil before installa-
tion.
(4) Align oil pump rotor flats with flats on crank-
shaft. Install the oil pump to the block.
CAUTION: To align, the front crankshaft seal MUST
be out of pump, or damage may result.
(5) Install new front crankshaft seal using Special
Tool 6780 (Fig. 88).
(6) Install crankshaft key (Fig. 82).
CAUTION: The crankshaft sprocket is set to a pre-
determined depth from the factory for correct tim-
ing belt tracking. If removed, use of Special Tool
6792 is required to set the sprocket to original
installation depth. An incorrectly installed sprocket
will result in timing belt and engine damage.
Fig. 84 Checking Oil Pump Cover Flatness
1 - STRAIGHT EDGE
2 - FEELER GAUGE
3 - OIL PUMP COVER
Fig. 85 Measuring Outer Rotor Thickness
Fig. 86 Measuring Inner Rotor Thickness
9s - 50 ENGINEKJ
OIL PUMP (Continued)

EXHAUST MANIFOLD
DESCRIPTION
The exhaust manifold is made of Hi-Silicone Moly
nodular cast iron for strength and high tempera-
tures. The manifold attaches to the cylinder head.
OPERATION
The exhaust manifold collects the exhaust gasses
exiting the combustion chambers. Then it channels
the exhaust gasses to the exhaust pipe attached to
the manifold.
REMOVAL
(1) Raise vehicle and disconnect exhaust pipe from
the exhaust manifold.
(2) Lower the vehicle.
(3) Disconnect upstream oxygen sensor connector
at the rear of exhaust manifold.
(4) Remove the air cleaner bracket (Fig. 91).
(5) Remove the heat shield.
(6) Remove the bolts attaching the manifold to the
cylinder head.
(7) Remove exhaust manifold.
(8) Inspect the manifold. (Refer to 9 - ENGINE/
MANIFOLDS/EXHAUST MANIFOLD - INSPEC-
TION)
CLEANING
(1) Discard gasket (if equipped) and clean all sur-
faces of manifold and cylinder head.
INSPECTION
(1) Inspect manifold gasket surfaces for flatness
with straight edge. Surface must be flat within 0.15
mm per 300 mm (0.006 in. per foot) of manifold
length.
(2) Inspect manifolds for cracks or distortion.
Replace manifold as necessary.
INSTALLATION
(1) Clean the manifold mating surfaces.
(2) Install exhaust manifold with a new gasket.
Tighten attaching nuts to 20 N´m (175 in. lbs.).
(3) Attach exhaust pipe to exhaust manifold and
tighten fasteners to 37 N´m (27 ft. lbs.).
(4) Install and connect the oxygen sensor. (Refer to
14 - FUEL SYSTEM/FUEL INJECTION/O2 SENSOR
- COMPONENT LOCATION)
(5) Install the heat shield.
(6) Install the air cleaner bracket.
TIMING BELT COVER(S)
REMOVAL
FRONT COVER
(1) Remove crankshaft vibration damper. (Refer to
9 - ENGINE/ENGINE BLOCK/VIBRATION
DAMPER - REMOVAL)
(2) Remove generator drive belt tensioner assem-
bly. (Refer to 7 - COOLING/ACCESSORY DRIVE/
BELT TENSIONERS - REMOVAL)
(3) Remove timing belt front cover bolts, and
remove covers.
REAR COVER
(1) Remove front covers.
(2) Remove timing belt. (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - REMOVAL)
(3) Hold camshaft sprocket with Special Tool 6847
while removing center bolt.
(4) Remove timing belt idler pulley.
(5) Remove rear cover fasteners and remove cover
from engine.
INSTALLATION
REAR COVER
(1) Install timing belt rear cover and bolts (Fig.
92). Torque bolts to 12 N´m (105 in. lbs).
Fig. 91 AIR CLEANER BRACKET
1 - AIR CLEANER BRACKET
2 - BOLT (2)
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CAUTION: Do not use an impact wrench for tighten-
ing camshaft sprocket bolt. Damage to the timing
locating pin can occur. Hand tighten using a
wrench ONLY.
(2) Install camshaft sprockets, and camshaft target
ring. Hold sprockets with Special Tool 6848 and
tighten center bolt to 101 N´m (75 ft. lbs.).
(3) Install timing belt idler pulley and tighten
mounting bolt to 61 N´m (45 ft. lbs.).
(4) Install timing belt. (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - INSTALLATION)
(5) Install accessory drive bracket (Fig. 93).
(6) Install front covers.
FRONT COVER
(1) Install timing belt front covers (Fig. 94).
Tighten fasteners to 7 N´m (60 in. lbs.).
(2) Install generator drive belt tensioner. (Refer to
7 - COOLING/ACCESSORY DRIVE/BELT TEN-
SIONERS - INSTALLATION)
(3) Install crankshaft vibration damper. (Refer to 9
- ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
INSTALLATION)
Fig. 92 TIMING BELT REAR COVER FASTENERS
1 - OUTER COVER TO REAR COVER FASTENERS (3)
2 - REAR COVER TO CYLINDER HEAD FASTENERS
3 - OUTER COVER TO REAR COVER FASTENERS (3)
4 - INNER COVER TO BLOCK FASTENERS
Fig. 93 ACCESSORY DRIVE BRACKET
1- UPPER TIMING BELT COVER
2- LOWER TIMING BELT COVER
3- BELT TENSIONER
4- ACCESSORY DRIVE BRACKET
Fig. 94 TIMING BELT COVERS
1- UPPER TIMING BELT COVER
2- REAR TIMING BELT COVER
3- LOWER TIMING BELT COVER
4- ACCESSORY DRIVE BRACKET NOT SHOWN
9s - 54 ENGINEKJ
TIMING BELT COVER(S) (Continued)

TIMING BELT AND
SPROCKET(S)
REMOVAL
REMOVAL - TIMING BELT
(1) Remove air cleaner upper cover, housing, and
clean air tube.
(2) Raise vehicle on hoist.
(3) Remove accessory drive belts. (Refer to 7 -
COOLING/ACCESSORY DRIVE/BELT TENSION-
ERS - REMOVAL)
(4) Remove crankshaft vibration damper. (Refer to
9 - ENGINE/ENGINE BLOCK/VIBRATION
DAMPER - REMOVAL)
(5) Remove air conditioner/generator belt tensioner
and pulley assembly. (Refer to 7 - COOLING/ACCES-
SORY DRIVE/BELT TENSIONERS - REMOVAL)
(6) Remove timing belt lower front cover bolts and
remove cover. (Refer to 9 - ENGINE/VALVE TIMING/
TIMING BELT / CHAIN COVER(S) - REMOVAL)
(7) Lower vehicle.
(8) Remove bolts attaching timing belt upper front
cover and remove cover. (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT / CHAIN COVER(S)
- REMOVAL)
CAUTION: When aligning crankshaft and camshaft
timing marks always rotate engine from crankshaft.
Camshaft should not be rotated after timing belt is
removed. Damage to valve components may occur.
Always align timing marks before removing timing
belt.
(9) Before the removal of the timing belt, rotate
crankshaft until the TDC mark on oil pump housing
aligns with the TDC mark on crankshaft sprocket
(trailing edge of sprocket tooth) (Fig. 95).
NOTE: The crankshaft sprocket TDC mark is
located on the trailing edge of the sprocket tooth.
Failure to align trailing edge of sprocket tooth to
TDC mark on oil pump housing will cause the cam-
shaft timing marks to be misaligned.
(10) Install 6 mm Allen wrench into belt tensioner.
Before rotating the tensioner, insert the long end of a
1/8º or 3 mm Allen wrench into the pin hole on the
front of the tensioner (Fig. 96). While rotating the
tensioner counterclockwise, push in lightly on the
1/8º or 3 mm Allen wrench, until it slides into the
locking hole.
(11) Remove timing belt.
REMOVAL - CRANKSHAFT SPROCKET
(1) Disconnect negative battery cable.
(2) Remove timing belt (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - REMOVAL).
(3) Remove crankshaft sprocket using Special
Tools 6793 and insert C-4685-C2 (Fig. 97).
CLEANING
Do Not attempt to clean a timing belt. If contami-
nation from oil, grease, or coolants have occurred, the
timing belt should be replaced.
Clean all sprockets using a suitable solvent. Clean
all sprocket grooves of any debris.
Fig. 95 Crankshaft and Camshaft Timing
1 - CAMSHAFT TIMING MARKS
2 - CRANKSHAFT TDC MARKS
3 - TRAILING EDGE OF SPROCKET TOOTH
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(8) Check if the spring tang is within the tolerance
window (Fig. 103). If the spring tang is within the
tolerance window, the installation process is complete
and nothing further is required. If the spring tang is
not within the tolerance window, repeat Steps 5
through 7.
(9) Install timing belt front covers and bolts.
(Refer to 9 - ENGINE/VALVE TIMING/TIMING
BELT / CHAIN COVER(S) - INSTALLATION)
(10) Install air conditioning/generator belt ten-
sioner and pulley. (Refer to 7 - COOLING/ACCES-
SORY DRIVE/BELT TENSIONERS -
INSTALLATION)
(11) Install crankshaft vibration damper. (Refer to
9 - ENGINE/ENGINE BLOCK/VIBRATION
DAMPER - INSTALLATION)
(12) Install accessory drive belts. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION)
(13) Install drive belt splash shield.
(14) Install air cleaner housing, upper cover, and
clean air tube.
Fig. 101 Timing Belt Tension Adjustment
1 - ALIGN SETTING NOTCH WITH SPRING TANG
2 - TOP PLATE
3 - 6mm ALLEN WRENCH
4 - LOCK NUT
5 - SETTING NOTCH
6 - SPRING TANG
Fig. 102 Crankshaft and Camshaft Timing
1 - CAMSHAFT TIMING MARKS
2 - CRANKSHAFT TDC MARKS
3 - TRAILING EDGE OF SPROCKET TOOTH
Fig. 103 Timing Belt Tension Verification
1 - SPRING TANG
2 - TOLERANCE WINDOW
9s - 58 ENGINEKJ
TIMING BELT AND SPROCKET(S) (Continued)

TIMING BELT TENSIONER &
PULLEY
REMOVAL
(1) Remove the timing belt. (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - REMOVAL)
(2) Remove timing belt idler pulley.
(3) Hold camshaft sprocket with Special Tool 6847
while removing bolt (Fig. 104). Remove both cam
sprockets.
(4) Remove rear timing belt cover fasteners and
remove cover from engine (Fig. 105).
(5) Remove lower bolt attaching timing belt ten-
sioner assembly to engine and remove tensioneras
an assembly.
INSTALLATION
(1) Align timing belt tensioner assembly to engine
and install lower mounting boltbut do not tighten.
To properly align tensioner assemblyÐinstall one of
the engine bracket mounting bolts (M10) 5 to 7 turns
into the tensioner's upper mounting location.
(2) Torque the tensioner's lower mounting bolt to
61 N´m (45 ft. lbs.). Remove the upper bolt used for
tensioner alignment.
(3) Install rear timing belt cover and fasteners.
(4) Install timing belt idler pulley and torque
mounting bolt to 61 N´m (45 ft. lbs.).(5) Install camshaft sprockets. Use Special Tool
6847 to hold sprockets, torque bolts to 101 N´m (75
ft. lbs.).
(6) Install the timing belt. (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - INSTALLATION)
BALANCE SHAFT
DESCRIPTION
The 2.4L engine is equipped with two nodular cast
iron balance shafts installed in a cast aluminum car-
rier attached to the lower cylinder block (Fig. 106).
OPERATION
The balance shafts are driven by the crankshaft
via a roller chain and sprockets. The balance shafts
are connected by helical gears. The dual counter
rotating shafts decrease second order vertical shak-
ing forces caused by component movement.
Fig. 104 Camshaft Sprocket - Removal/Installation
1 - SPECIAL TOOL 6847
Fig. 105 TIMING BELT REAR COVER FASTENERS
1 - OUTER COVER TO REAR COVER FASTENERS (3)
2 - REAR COVER TO CYLINDER HEAD FASTENERS
3 - OUTER COVER TO REAR COVER FASTENERS (3)
4 - INNER COVER TO BLOCK FASTENERS
KJENGINE9s-59