2002 JEEP LIBERTY check engine

INSPECTION
The crankshaft journals should be checked for
excessive wear, taper and scoring (Fig. 42). Limits of
taper or out of round on any crankshaft journals
should within specitifications. (Refer to 9 - ENGINE -
SPECIFICATIONS) Journal grinding should not
exceed 0.305 mm (0.012 in.) under the standard jour-
nal diameter. DO NOT grind thrust faces of No. 3
main bearing. DO NOT nick crank pin or bearing fil-
lets. After grinding, remove rough edges from crank-
shaft oil holes and clean out all passages.
CAUTION: With the nodular cast iron crankshafts, it
is important that the final paper or cloth polish be
in the same direction as normal rotation in the
engine.
INSTALLATION
(1) Install the main bearing shells with the lubri-
cation groove in the cylinder block (Fig. 43).
(2) Make certain oil holes in block line up with oil
hole in bearings and bearing tabs seat in the block
tab slots.
CAUTION: Do not get oil on the bedplate mating
surface. It will affect the sealer ability to seal the
bedplate to cylinder block.
(3) Oil the bearings and journals. Install crank-
shaft.
CAUTION: Use only the specified anaerobic sealer
on the bedplate or damage may occur to the
engine.
(4) Apply 1.5 to 2.0 mm (0.059 to 0.078 in.) bead of
MopartBed Plate Sealant to cylinder block as shown
in (Fig. 44).
(5) Install lower main bearings into main bearing
cap/bedplate. Make certain the bearing tabs areseated into the bedplate slots. Install the main bear-
ing/bedplate into engine block.
Fig. 42 Crankshaft Journal Measurements
Fig. 43 Installing Main Bearing Upper Shell
1 - LUBRICATION GROOVES
2 - OIL HOLES
Fig. 44 Bedplate Sealing
Fig. 45 Bedplate Bolt Torque Sequence
9s - 34 ENGINEKJ
CRANKSHAFT (Continued)

(6) Before installing the bolts the threads should
be oiled with clean engine oil, wipe off any excess oil.
(7) Install main bearing bedplate to engine block
bolts 11, 17, and 20 finger tight. Tighten these bolts
down together until the bedplate contacts the cylin-
der block.
(8) To ensure correct thrust bearing alignment,
perform the following steps:
²Step 1: Rotate crankshaft until number 4 piston
is at TDC.
²Step 2: Move crankshaft rearward to limits of
travel.
²Step 3: Then, move crankshaft forward to limits
of travel.
²Step 4: Wedge an appropriate tool between the
rear of the cylinder block(NOT BED PLATE)and
the rear crankshaft counterweight. This will hold the
crankshaft in it's furthest forward position.
²Step 5: Install and tighten bolts (1±10) in
sequence shown in (Fig. 45) to 41 N´m (30 ft. lbs.).
²Step 6: Remove wedge tool used to hold crank-
shaft.
(9) Tighten bolts (1±10) again to 41 N´m (30 ft.
lbs.) +1/4 turn in sequence shown in (Fig. 45).
(10) Install main bearing bedplate to engine block
bolts (11±20), and torque each bolt to 28 N´m (20 ft.
lbs.) in sequence shown in (Fig. 45).
(11) After the main bearing bedplate is installed,
check the crankshaft turning torque. The turning
torque should not exceed 5.6 N´m (50 in. lbs.).
(12) Install balance shafts and housing assembly.
(Refer to 9 - ENGINE/VALVE TIMING/BALANCE
SHAFT - INSTALLATION)
(13) Install the oil pump and pickup tube. (Refer
to 9 - ENGINE/LUBRICATION/OIL PUMP -
INSTALLATION)
(14) Install the timing belt rear cover. (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION)
(15) Install the timing belt. (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - INSTALLATION)
(16) Install the timing belt front covers. (Refer to 9
- ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION)
(17) Install engine support bracket.
(18) Install the oil pan. (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - INSTALLATION)
(19) Install the oil filter.
(20) Install crankshaft rear oil seal. (Refer to 9 -
ENGINE/ENGINE BLOCK/CRANKSHAFT OIL
SEAL - REAR - INSTALLATION)
(21) Install flex plate. Apply MopartLock & Seal
Adhesive to bolt threads and tighten to 95 N´m (70
ft. lbs.).(22) Install the engine assembly. (Refer to 9 -
ENGINE - INSTALLATION)
CRANKSHAFT MAIN
BEARINGS
STANDARD PROCEDURE - MAIN BEARING -
FITTING
For crankshaft specifications (Refer to 9 - ENGINE
- SPECIFICATIONS).
CRANKSHAFT MAIN BEARINGS
The crankshaft is supported in five main bearings.
All upper and lower bearing shells in the crankcase
have oil grooves. Crankshaft end play is controlled by
a flanged bearing on the number three main bearing
journal (Fig. 46).
Upper and lower Number 3 bearing halves are
flanged to carry the crankshaft thrust loads and are
NOT interchangeable with any other bearing halves
in the engine (Fig. 46). All bearing cap bolts removed
during service procedures are to be cleaned and oiled
before installation. Bearing shells are available in
standard and the following undersized: 0.025 mm
(0.001 in.) and 0.250 mm (0.010 in.). Never install an
undersize bearing that will reduce clearance below
specifications. Replace or machine the crankshaft as
necessary to obtain proper bearing clearances.
MAIN BEARING INSTALLATION
(1) Install the main bearing shells with the lubri-
cation groove in the cylinder block (Fig. 47).
Fig. 46 Main Bearing Identification
1 - OIL GROOVE
2 - MAIN BEARINGS
3 - OIL HOLE
KJENGINE9s-35
CRANKSHAFT (Continued)

(2) Make certain oil holes in block line up with oil
holes in bearings. Bearing tabs must seat in the
block tab slots.
CAUTION: Do not get oil on the bedplate mating
surface. It will may effect the sealer ability to seal
the bedplate to cylinder block.
(3) Oil the bearings and journals and install
crankshaft.
CAUTION: Use only the specified anaerobic sealer
on the bedplate or damage may occur to the
engine. Ensure that both cylinder block and bed-
plate surfaces are clean.
(4) Apply 1.5 to 2.0 mm (0.059 to 0.078 in.) bead
of anaerobic sealer MopartBed Plate Sealant to cyl-
inder block as shown in (Fig. 48).(5) Install lower main bearings into main bearing
cap/bedplate. Make certain the bearing tabs are
seated into the bedplate slots.
(6) Position the main bearing/bedplate onto the
engine block.
(7) Before installing bolts, lubricate the threads
with clean engine oil, wipe off any excess oil.
(8) Install main bearing bedplate to engine block
bolts 11, 17 and 20 finger tight. Tighten these bolts
down together until the bedplate contacts the cylin-
der block.
(9) To ensure correct thrust bearing alignment,
perform the following steps:
²Step 1: Rotate crankshaft until number 4 piston
is at TDC.
²Step 2: Move crankshaft rearward to limits of
travel.
²Step 3: Then, move crankshaft forward to limits
of travel.
²Step 4: Wedge an appropriate tool between the
rear of the cylinder block(NOT BED PLATE)and
the rear crankshaft counterweight. This will hold the
crankshaft in it's furthest forward position.
²Step 5: Install and tighten bolts (1±10) in
sequence shown in (Fig. 49) to 41 N´m (30 ft. lbs.).
²Step 6: Remove wedge tool used to hold crank-
shaft.
(10) Tighten bolts (1±10) again to 41 N´m (30 ft.
lbs.)PLUS1/4 turn in sequence shown in (Fig. 49).
(11) Install main bearing bedplate to engine block
bolts (11±20), and torque each bolt to 28 N´m (20 ft.
lbs.) in sequence shown in (Fig. 49).
(12) After the main bearing bedplate is installed,
check the crankshaft turning torque. The turning
torque should not exceed 5.6 N´m (50 in. lbs.).
Fig. 47 Installing Main Bearing Upper Shell
1 - LUBRICATION GROOVES
2 - OIL HOLES
Fig. 48 Main Bearing Caps/Bedplate Sealing
Fig. 49 Main Bearing Caps/Bedplate Tightening
Sequence
9s - 36 ENGINEKJ
CRANKSHAFT MAIN BEARINGS (Continued)

INSTALLATION
(1) Before installing pistons and connecting rod
assemblies into the bore, be sure that compression
ring gaps are staggered so that neither is in line with
oil ring rail gap.
(2) Before installing the ring compressor, make
sure the oil ring expander ends are butted and the
rail gaps located as shown in (Fig. 62). As viewed
from top.
(3) Immerse the piston head and rings in clean
engine oil, slide the ring compressor, over the piston
(Fig. 63).Be sure position of rings does not
change during this operation.
(4) The directional stamp on the piston should face
toward the front of the engine.
(5) Rotate crankshaft so that the connecting rod
journal is on the center of the cylinder bore. Insert
rod and piston assembly into cylinder bore and guide
rod over the crankshaft journal.(6) Tap the piston down in cylinder bore, using a
hammer handle. At the same time, guide connecting
rod into position on connecting rod journal.
NOTE: The connecting rod cap bolts should not be
reused.
(7) Before installing theNEWbolts the threads
should be coated with clean engine oil.
(8) Install each bolt finger tight than alternately
torque each bolt to assemble the cap properly.
CAUTION: Do not use a torque wrench for second
part of last step.
(9) Tighten the bolts to 54 N´m PLUS 1/4 turn (40
ft. lbs. PLUS 1/4 turn).
(10) Using a feeler gauge, check connecting rod
side clearance (Fig. 64).
Fig. 61 Identify Connecting Rod to Cylinder
Fig. 62 Piston Ring End Gap Position
1 - GAP OF LOWER SIDE RAIL
2 - NO. 1 RING GAP
3 - GAP OF UPPER SIDE RAIL
4 - NO. 2 RING GAP AND SPACER EXPANDER GAP
Fig. 63 PistonÐInstallation
Fig. 64 Checking Connecting Rod Side Clearance
KJENGINE9s-41
PISTON & CONNECTING ROD (Continued)

PISTON RINGS
STANDARD PROCEDURE
PISTON RING - FITTING
(1) Wipe cylinder bore clean. Insert ring and push
down with piston to ensure it is square in bore. The
ring gap measurement must be made with the ring
positioning at least 12 mm (0.50 inch) from bottom of
cylinder bore. Check gap with feeler gauge (Fig. 65).
Refer to Engine Specifications.
(2) Check piston ring to groove side clearance (Fig.
66). Refer to Engine Specifications.
PISTON RINGS - INSTALLATION
(1) Install rings with manufacturers I.D. mark fac-
ing up, to the top of the piston (Fig. 67).
CAUTION: Install piston rings in the following
order:
a. Oil ring expander.
b. Upper oil ring side rail.
c. Lower oil ring side rail.
d. No. 2 Intermediate piston ring.
e. No. 1 Upper piston ring.
(2) Install the side rail by placing one end
between the piston ring groove and the expander.
Hold end firmly and press down the portion to be
installed until side rail is in position.Do not use a
piston ring expander(Fig. 68).
(3) Install upper side rail first and then the lower
side rail.
(4) Install No. 2 piston ring and then No. 1 piston
ring.
(5) Position piston ring end gaps as shown in (Fig.
69).
(6) Position oil ring expander gap at least 45É
from the side rail gaps butnoton the piston pin cen-
ter or on the thrust direction. Staggering ring gap is
important for oil control.
Fig. 65 Piston Ring Gap
1 - FEELER GAUGE
Fig. 66 Piston Ring Side Clearance
1 - FEELER GAUGE
Fig. 67 Piston Ring Installation
1 - NO. 1 PISTON RING
2 - NO. 2 PISTON RING
3 - SIDE RAIL
4 - OIL RING
5 - SPACER EXPANDER
9s - 42 ENGINEKJ

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)

(6) Install oil pressure switch and connector. (Refer
to 9 - ENGINE/LUBRICATION/OIL PRESSURE
SENSOR/SWITCH - INSTALLATION)
OIL
STANDARD PROCEDURE
ENGINE OIL LEVEL CHECK
The best time to check engine oil level is after it
has sat overnight, or if the engine has been running,
allow the engine to be shut off for at least 5 minutes
before checking oil level.
Checking the oil while the vehicle is on level
ground will improve the accuracy of the oil level
reading. Remove dipstick and observe oil level. Add
oil only when the level is at or below the ADD mark
(Fig. 78).
STANDARD PROCEDURE - ENGINE OIL AND
FILTER CHANGE
Change engine oil at mileage and time intervals
described in the Maintenance Schedule. (Refer to
LUBRICATION & MAINTENANCE/MAINTE-
NANCE SCHEDULES - DESCRIPTION)
WARNING: NEW OR USED ENGINE OIL CAN BE
IRRITATING TO THE SKIN. AVOID PROLONGED OR
REPEATED SKIN CONTACT WITH ENGINE OIL.
CONTAMINANTS IN USED ENGINE OIL, CAUSED BY
INTERNAL COMBUSTION, CAN BE HAZARDOUS TO
YOUR HEALTH. THOROUGHLY WASH EXPOSED
SKIN WITH SOAP AND WATER. DO NOT WASH
SKIN WITH GASOLINE, DIESEL FUEL, THINNER, OR
SOLVENTS, HEALTH PROBLEMS CAN RESULT. DO
NOT POLLUTE, DISPOSE OF USED ENGINE OIL
PROPERLY. CONTACT YOUR DEALER OR GOVERN-
MENT AGENCY FOR LOCATION OF COLLECTION
CENTER IN YOUR AREA.
Run engine until achieving normal operating tem-
perature.
(1) Position the vehicle on a level surface and turn
engine off.(2) Hoist and support vehicle on safety stands.
Refer to Hoisting and Jacking Recommendations.
(Refer to LUBRICATION & MAINTENANCE/HOIST-
ING - STANDARD PROCEDURE)
(3) Remove oil fill cap.
(4) Place a suitable drain pan under crankcase
drain.
(5) Remove drain plug from crankcase and allow
oil to drain into pan. Inspect drain plug threads for
stretching or other damage. Replace drain plug and
gasket if damaged.
(6) Remove oil filter. (Refer to 9 - ENGINE/LUBRI-
CATION/OIL FILTER - REMOVAL)
(7) Install and tighten drain plug in crankcase.
(8) Install new oil filter. (Refer to 9 - ENGINE/LU-
BRICATION/OIL FILTER - INSTALLATION)
(9) Lower vehicle and fill crankcase with specified
type and amount of engine oil. (Refer to LUBRICA-
TION & MAINTENANCE/FLUID TYPES -
DESCRIPTION)
(10) Install oil fill cap.
(11) Start engine and inspect for leaks.
(12) Stop engine and inspect oil level.
NOTE: Care should be exercised when disposing
used engine oil after it has been drained from a
vehicle engine. Refer to the WARNING listed above.
OIL FILTER
DESCRIPTION
The engine oil filter is a high quality full-flow, dis-
posable type. Replace the oil filter with a Mopartor
the equivalent.
REMOVAL
(1) Raise vehicle on hoist.
(2) Position an oil collecting container under oil fil-
ter location.
CAUTION: When servicing the oil filter avoid
deforming the filter can by installing the remove/in-
stall tool band strap against the can to base lock
seam. The lock seam joining the can to the base is
reinforced by the base plate.
(3) Using a suitable filter wrench, turn oil filter
counterclockwise to remove (Fig. 79).
INSTALLATION
(1) Clean and check filter mounting surface. The
surface must be smooth, flat and free of debris or
pieces of gasket.
(2) Lubricate new oil filter gasket with clean
engine oil.
Fig. 78 Oil Level
1 - ENGINE OIL LEVEL DIPSTICK
KJENGINE9s-47
LUBRICATION (Continued)

instrument panel on either a CCD or PCI bus circuit
(depending on vehicle line) to operate the oil pressure
gauge and the check gauges lamp. Ground for the
sensor is provided by the PCM through a low-noise
sensor return.
OIL PUMP
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove timing belt. (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - REMOVAL)
(3) Remove timing belt rear cover. (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL)
(4) Remove oil pan. (Refer to 9 - ENGINE/LUBRI-
CATION/OIL PAN - REMOVAL)
(5) Remove crankshaft sprocket using Special
Tools 6793 and C-4685-C2 (Fig. 81).
(6) Remove crankshaft key (Fig. 82).
(7) Remove oil pick-up tube.
(8) Remove oil pump (Fig. 83) and front crankshaft
seal.
DISASSEMBLY
(1) To remove the relief valve, proceed as follows:
(a) Remove the threaded plug and gasket from
the oil pump.
(b) Remove spring and relief valve.
(2) Remove oil pump cover fasteners, and lift off
cover.
(3) Remove pump rotors.
(4) Wash all parts in a suitable solvent and
inspect carefully for damage or wear.
CLEANING
(1) Clean all parts thoroughly in a suitable sol-
vent.
Fig. 81 Crankshaft Sprocket - Removal
1 - SPECIAL TOOL 6793
2 - SPECIAL TOOL C-4685±C2
3 - CRANKSHAFT SPROCKET
Fig. 82 Crankshaft Key
1 - CRANKSHAFT KEY
Fig. 83 2.4L OIL PUMP
1 - BOLTS
2 - BOLTS
KJENGINE9s-49
OIL PRESSURE SENSOR/SWITCH (Continued)