2002 JEEP LIBERTY Egr

DESCRIPTION SPECIFICATION
Exhaust 6.60 mm
(0.259 t>
Intake Valve Timing*
Closes (ABDC) 51É
Opens (BTDC) 1É
Duration 232É
Exhaust Valve Timing*
Closes (ATDC) 7É
Opens (BBDC) 47É
Duration 234É
Valve Overlap 8É
*All readings in crankshaft degrees. Timing points @
4É from top of Ramps.
Cylinder Head
Material Cast Aluminum
Gasket Thickness
(Compressed)0.71 mm
(0.028 in.)
Valve Seat
Angle 44.5±45É
Seat DiameterÐIntake 34.37±34.63 mm
(1.353±1.363 in.)
Seat DiameterÐExhaust 27.06±27.32 mm
(1.065±1.075 in.)
Runout (Max.) 0.05 mm
(0.002 in.)
Valve Seat WidthÐIntake
and Exhaust0.9±1.3 mm
(0.035±0.051 in.)
Service LimitÐIntake 2.0 mm
(0.079 in.)
Service LimitÐExhaust 2.5 mm
(0.098 in.)
Valve Guide
Diameter I.D. 5.975±6.000 mm
(0.235±0.236 in.)
Guide Bore Diameter 11.0±11.02 mm
(0.4330±0.4338 in.)
Guide Height (spring seat
to guide tip)13.25±13.75 mm
(0.521±0.541 in.)
Valves
Face AngleÐIntake and
Exhaust44.5Ð45ÉDESCRIPTION SPECIFICATION
Head DiameterÐIntake 34.67±34.93 mm
1.364±1.375 in.)
Head DiameterÐExhaust 28.32±28.52 mm
(1.114±1.122 in.)
Valve Length (Overall)
ÐIntake 112.76±113.32 mm
(4.439±4.461 in.)
ÐExhaust 110.89±111.69 mm
(4.365±4.397 in.)
Valve Stem Diameter
ÐIntake 5.934±5.952 mm
(0.2337±0.2344 in.)
ÐExhaust 5.906±5.924 mm
(0.2326±0.2333 in.)
Valve Margin
Intake 1.2±1.7 mm
(0.047±0.066 in.)
Service Limit 0.95 mm
(1/32 in.)
Exhaust 0.985±1.315 mm
(0.038±0.051 in.)
Service Limit 1.05 mm
(3/64 in.)
Valve Stem Tip
Intake 48.04 mm
(1.891 in.)
Exhaust 47.99 mm
(1.889 in.)
Valve Stem to Guide Clearance
Intake 0.048±0.066 mm
(0.0018±0.0025 in.)
Max. Allowable 0.076 mm
(0.003 in.)
Service Limit 0.25 mm
(0.010 in.)
Exhaust 0.0736±0.094 mm
(0.0029±0.0037 in.)
Max. Allowable 0.101 mm
(0.004 in.)
Service Limit 0.25 mm
(0.010 in.)
KJENGINE9s-15
ENGINE - 2.4L (Continued)

AIR CLEANER ELEMENT
REMOVAL - 2.4L
Housing removal is not necessary for element (fil-
ter) replacement.
(1) Disconnect air intake duct at side of element
cover.
(2) Pry up 2 spring clips from front of housing
cover (spring clips retain cover to housing).
(3) Release housing cover from locating tabs
located on rear of housing, and remove cover.
(4) Remove air cleaner element (filter) from hous-
ing.
(5) Clean inside of housing before replacing ele-
ment.
INSTALLATION - 2.4L
(1) Install element into housing.
(2) Position housing cover into housing locating
tabs.
(3) Pry up spring clips and lock cover to housing.
(4) Connect air intake duct.
If any air filter, air resonator, air intake tubes or
air filter housing clamps had been loosened or
removed, tighten them to 5 N´m (40 in. lbs.) torque.
CYLINDER HEAD
DESCRIPTION
The cross flow designed, aluminum cylinder head
contains dual over-head camshafts with four valves
per cylinder (Fig. 5). The valves are arrange in two
in-line banks. The intake valves face toward the left
side of the vehicle. The exhaust valves face the right
side. The cylinder head incorporates powdered metalvalve guides and seats. The cylinder head is sealed to
the block using a multi-layer steel head gasket and
retaining bolts.
Integral oil galleries providing lubrication passages
to the hydraulic lash adjusters, camshafts, and valve
mechanisms.
OPERATION
The cylinder head closes the combustion chamber,
allowing the pistons to compress the fuel/air mixture
for ignition. The valves are actuated by the lobe pro-
files on the camshaft to open and close at specified
duration to either allow clean air in the combustion
chamber or the exhaust gases out; depending on the
stroke of the engine.
DIAGNOSIS AND TESTING - CYLINDER HEAD
GASKET
A cylinder head gasket leak can be located between
adjacent cylinders or between a cylinder and the
adjacent water jacket.
Possible indications of the cylinder head gasket
leaking between adjacent cylinders are:
²Loss of engine power
²Engine misfiring
²Poor fuel economy
Combustion Leak Tester C-3685-A
Cylinder Compression Pressure Adaptor 8116
Fig. 5 Cylinder Head and Camshafts
CAM PLUG - NOT SHOWN
1 - CAMSHAFT BEARING CAPS
2 - PLUG
3 - CAMSHAFT
4 - CYLINDER HEAD
5 - CAMSHAFT OIL SEAL
KJENGINE9s-19
ENGINE - 2.4L (Continued)

(4) Install cylinder head cover assembly to cylin-
der head. Install all bolts, ensuring the two (2) bolts
containing the sealing washer are located in the cen-
ter locations of cover. Tighten bolts in sequence
shown in (Fig. 25). Using a 3 step torque method as
follows:
(a) Tighten all bolts to 4.5 N´m (40 in. lbs.).
(b) Tighten all bolts to 9.0 N´m (80 in. lbs.).
(c) Tighten all bolts to 12 N´m (105 in. lbs.).
(5) Install intake manifold.
(6) Install ignition coil and spark plug wires.
Tighten fasteners to 12 N´m (105 in. lbs.).
(7) If the PCV valve was removed, apply Mopart
Thread Sealant with Teflon to threads and install
valve to cylinder head cover. Tighten PCV valve to 8
N´m (70 in. lbs.).
(8) Connect PCV and make-up air hoses to cylin-
der head cover.
INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
The four valves per cylinder are opened by using
roller rocker arms which pivot on hydraulic lash
adjusters. The valves have chrome plated valve
stems. Viton rubber valve stem seals are integral
with the spring seats.They have chrome plated stems
to prevent scuffing. Viton rubber valve stem seals are
integral with the spring seats. The valves, spring
retainers,and locks, are the 3 - bead lock design
CLEANING
(1) Clean all valves thoroughly and discard
burned, warped and cracked valves.
VALVE SPRINGS
REMOVAL
REMOVAL - CYLINDER HEAD ON
(1) Remove camshafts.
(2) Rotate crankshaft until piston is at TDC on
compression.
(3) With air hose attached to adapter tool installed
in spark plug hole, apply 90-120 psi air pressure.
(4) Using Special Tool MD-998772-A with adapter
6779 (Fig. 26), compress valve springs and remove
valve locks.
(5) Remove valve spring(s).
(6) Remove valve stem seal(s) by a using valve
stem seal tool (Fig. 28).
REMOVAL - CYLINDER HEAD OFF
(1) With cylinder head removed from cylinder
block, compress valve springs using a universal valve
spring compressor.
(2) Remove valve retaining locks, valve spring
retainers, valve stem seals and valve springs.
(3) Before removing valves,remove any burrs
from valve stem lock grooves to prevent dam-
age to the valve guides.Identify valves, locks and
retainers to insure installation in original location.
(4) Inspect the valves. (Refer to 9 - ENGINE/CYL-
INDER HEAD/VALVE SPRINGS - INSPECTION)
Fig. 25 CYLINDER HEAD TIGHTENING SEQUENCE
Fig. 26 Valve Spring - Removal/Installation
1 - VALVE SPRING COMPRESSOR MD 998772A
2 - AIR HOSE
KJENGINE9s-27
CYLINDER HEAD COVER (Continued)

(2) Insufficient running time after rebuilding cylin-
der head. Low speed running up to 1 hour may be
required.
(3) During this time, turn engine off and let set for
a few minutes before restarting. Repeat this several
times after engine has reached normal operating
temperature.
(4) Low oil pressure.
(5) The oil restrictor (integral to the head gasket)
in the vertical oil passage to the cylinder head is
plugged with debris.
(6) Air ingested into oil due to broken or cracked
oil pump pick up.
(7) Worn valve guides.
(8) Rocker arm ears contacting valve spring
retainer.
(9) Rocker arm loose, adjuster stuck or at maxi-
mum extension and still leaves lash in the system.
(10) Faulty lash adjuster.
a. Check lash adjusters for sponginess while
installed in cylinder head. Depress part of rocker
arm over adjuster. Normal adjusters should feel very
firm. Spongy adjusters can be bottomed out easily.
b. Remove suspected lash adjusters, and replace as
necessary.
REMOVAL
NOTE: This procedure is for in-vehicle service with
camshafts installed.
(1) Remove cylinder head cover. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL)
(2) Remove the camshafts (Refer to 9 - ENGINE/
CYLINDER HEAD/CAMSHAFT(S) - REMOVAL).
(3) Remove rocker arm. (Refer to 9 - ENGINE/
CYLINDER HEAD/ROCKER ARMS - REMOVAL)
(4) Remove hydraulic lifter (Fig. 30).(5) Repeat removal procedure for each hydraulic
lifter.
(6) If reusing, mark each hydraulic lifter for reas-
sembly in original position. Lifters are serviced as an
assembly.
INSTALLATION
(1) Install hydraulic lifter (Fig. 30). Ensure the
lifters are at least partially full of engine oil. This is
indicated by little or no plunger travel when the
lifter is depressed.
(2) Install rocker arm. (Refer to 9 - ENGINE/CYL-
INDER HEAD/ROCKER ARMS - INSTALLATION)
(3) Repeat installation procedure for each hydrau-
lic lifter.
(4) Install camshafts (Refer to 9 - ENGINE/CYL-
INDER HEAD/CAMSHAFT(S) - INSTALLATION).
(5) Install cylinder head cover. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION)
ROCKER ARMS
REMOVAL
NOTE: This procedure is for in-vehicle service with
camshafts installed.
(1) Remove cylinder head cover. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL)
(2) Remove fuel rail. (Refer to 14 - FUEL SYS-
TEM/FUEL DELIVERY/FUEL RAIL - REMOVAL)
(3) Remove spark plugs.
(4) Rotate engine until the camshaft lobe, on the
follower being removed, is position on its base circle
(heel). Also, the piston should be a minimum of 6.3
mm (0.25 in) below TDC position.
Fig. 29 Checking Spring Installed Height and Valve
Tip Height Dimensions
1 - GARTER SPRING
2 - VALVE SPRING SEAT
3 - CYLINDER HEAD SURFACE
Fig. 30 Hydraulic Lash Adjuster
KJENGINE9s-29
HYDRAULIC LIFTERS (Continued)

CAUTION: If cam follower assemblies are to be
reused, always mark position for reassembly in
their original positions.
(5) Using Special Tools 8215 and 8436 slowly
depress valve assembly until rocker arm can be
removed (Fig. 31).
NOTE: It may be necessary to remove additional
brackets or components to allow clearance for tool
handle movement.
(6) Repeat removal procedure for each rocker arm.
INSPECTION
Inspect the rocker arm for wear or damage (Fig.
32). Replace as necessary.
INSTALLATION
(1) Lubricate rocker arm with clean engine oil.
(2) Using Special Tools 8215 and 8436 slowly
depress valve assembly until rocker arm can be
installed on the hydraulic lifter and valve stem.
(3) Repeat installation procedure for each rocker
arm.
(4) Install spark plugs.
(5) Install fuel rail. (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/FUEL RAIL - INSTALLATION)
(6) Install cylinder head cover. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION)
ENGINE BLOCK
DESCRIPTION
The cast iron cylinder block is a two-piece assem-
bly, consisting of the cylinder block and bedplate (Fig.
33). The bedplate incorporates the main bearing caps
and bolts to the cylinder block. This design offers a
much stronger lower end and increased cylinder
block rigidity. The rear oil seal retainer is integral
with the block. The bedplate and block are serviced
as an assembly.
STANDARD PROCEDURE
STANDARD PROCEDURE - PISTON TO
CYLINDER BORE FITTING
Piston and cylinder wall must be clean and dry.
Piston diameter should be measured 90 degrees to
piston pin about 14 mm (9/16 inch.) from the bottom
of the skirt as shown in (Fig. 35). Cylinder bores
should be measured halfway down the cylinder bore
and transverse to the engine crankshaft center line
Fig. 31 Rocker Arm - Removal/Installation
1 - SPECIAL TOOL 8215
2 - ROCKER ARM
3 - SPECIAL TOOL 8436
Fig. 32 Rocker Arm - Typical
1 - TIP
2 - LASH ADJUSTER POCKET
3 - ROLLER
Fig. 33 2.4L Cylinder Block and Bedplate - Typical
1 - CYLINDER BLOCK
2 - BEDPLATE
9s - 30 ENGINEKJ
ROCKER ARMS (Continued)

shown in (Fig. 34). Refer to for Engine Specifications
(Refer to 9 - ENGINE - SPECIFICATIONS). Correct
piston to bore clearance must be established in order
to assure quiet and economical operation.
NOTE: Pistons and cylinder bores should be mea-
sured at normal room temperature, 21ÉC (70ÉF).
STANDARD PROCEDURE - CYLINDER BORE
HONING
(1) Used carefully, the cylinder bore resizing hone,
recommended tool C-823 or equivalent, equipped
with 220 grit stones, is the best tool for this honing
procedure. In addition to deglazing, it will reduce
taper and out-of-round as well as removing light
scuffing, scoring or scratches. Usually a few strokes
will clean up a bore and maintain the required lim-
its.
(2) Deglazing of the cylinder walls may be done
using a cylinder surfacing hone, recommended toolC-3501 or equivalent, equipped with 280 grit stones,
if the cylinder bore is straight and round. 20±60
strokes depending on the bore condition, will be suf-
ficient to provide a satisfactory surface. Use a light
honing oil.Do not use engine or transmission oil,
mineral spirits or kerosene.Inspect cylinder walls
after each 20 strokes.
(3) Honing should be done by moving the hone up
and down fast enough to get a cross-hatch pattern.
When hone marksintersectat 40-60 degrees, the
cross hatch angle is most satisfactory for proper seat-
ing of rings (Fig. 36).
(4) A controlled hone motor speed between
200±300 RPM is necessary to obtain the proper cross-
hatch angle. The number of up and down strokes per
minute can be regulated to get the desired 40±60
degree angle. Faster up and down strokes increase
the cross-hatch angle.
(5) After honing, it is necessary that the block be
cleaned again to remove all traces of abrasive.
CAUTION: Ensure all abrasives are removed from
engine parts after honing. It is recommended that a
solution of soap and hot water be used with a
brush and the parts then thoroughly dried. The bore
can be considered clean when it can be wiped
clean with a white cloth and cloth remains clean.
Oil the bores after cleaning to prevent rusting.
CLEANING
Clean cylinder block thoroughly using a suitable
cleaning solvent.
Fig. 34 Checking Cylinder Bore -Typical
Fig. 35 Piston Measurement - Typical
Fig. 36 Cylinder Bore Cross-Hatch Pattern
1 - CROSS-HATCH PATTERN
2 - 40ɱ60É
KJENGINE9s-31
ENGINE BLOCK (Continued)

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)

(2) Spray a small stream of water (Spray Bottle) at
the suspected leak area.
(3) If engine RPM'S change, the area of the sus-
pected leak has been found.
(4) Repair as required.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Disconnect connector from inlet air tempera-
ture sensor.
(3) Disconnect air intake tube at throttle body and
remove upper air cleaner housing.
(4) Disconnect connector from throttle position
sensor (TPS).
(5) Disconnect connector from idle air control (IAC)
motor.
(6) Disconnect connector from MAP sensor.
(7) Remove vacuum lines for purge solenoid and
PCV valve at intake manifold.
(8) Remove vacuum lines for power brake booster,
LDP, EGR transducer, and speed control vacuum res-
ervoir (if equipped) at intake manifold fittings.
(9) Disconnect throttle, speed control (if equipped),
and transaxle control (if equipped) and cables from
throttle lever and bracket. (Refer to 14 - FUEL SYS-
TEM/FUEL INJECTION/THROTTLE CONTROL
CABLE - REMOVAL)
(10) Perform fuel system pressure release proce-
durebefore attempting any repairs.(Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY - STANDARD
PROCEDURE)
(11) Disconnect fuel line. (Refer to 14 - FUEL SYS-
TEM/FUEL DELIVERY/QUICK CONNECT FIT-
TING - STANDARD PROCEDURE)
(12) Disconnect coolant temperature sensor/fuel
injector wire harness connector.
(13) Disconnect fuel injector harness.
(14) Remove intake manifold to cylinder head fas-
teners.
(15) Remove the manifold from engine.
CAUTION: Cover intake manifold openings to pre-
vent foreign material from entering engine.
(16) Inspect the manifold. (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - INSPECTION)
INSPECTION
(1) Check manifold 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 manifold for cracks or distortion.
Replace manifold if necessary.
INSTALLATION
(1) Clean manifold sealing surfaces.
(2) Install new manifold to cylinder head seals.
(3) Install manifold to head.
(4) Install and tighten intake manifold fasteners to
28 N´m (250 in. lbs.) in the sequence shown (Fig. 90).
Repeat procedure until all bolts are at specified
torque.
(5) Install throttle cables in bracket.
(6) Connect throttle, speed control, (if equipped),
cables to throttle lever.
(7) Connect vacuum lines for power brake booster,
LDP, EGR transducer, and speed control vacuum res-
ervoir (if equipped) at upper intake manifold fittings.
(8) Connect vacuum lines for purge solenoid and
PCV valve.
(9) Connect electrical connectors for MAP sensor,
throttle position sensor (TPS), and idle air control
(IAC) motor.
(10) Connect the fuel line. (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY/QUICK CONNECT FIT-
TING - STANDARD PROCEDURE)
(11) Connect coolant temperature sensor/fuel injec-
tor wiring harness electrical connector.
(12) Install the air cleaner housing and air intake
tube to throttle body.
(13) Connect inlet air temperature sensor connec-
tor.
(14) Connect negative cable to battery.
Fig. 90 LOWER INTAKE MANIFOLD TIGHTENING
SEQUENCE
9s - 52 ENGINEKJ
INTAKE MANIFOLD (Continued)