JEEP XJ 1995 Service And Repair Manual

(26) Connect the speed control cable, if equipped.
(27) Connect the throttle cable linkages.
(28) Connect the heater hoses at the engine ther-
mostat housing and water pump.
(29) Install the fan assembly to the idler pulley.
(30) Install the radiator or radiator and condenser
(if equipped with A/C).
(31) Connect the service valves to the A/C compres-
sor ports, if equipped with A/C.
(32) Charge the air conditioner system.
(33) Connect radiator fan switch wire.
(34) Connect automatic transmission fluid cooler
lines, if equipped.
(35) Install the fan shroud, electric cooling fan and
radiator and condenser (if equipped with A/C).
(36) Install upper radiator support.
(37) Connect the upper radiator hose.
(38) Connect the lower radiator hose.
(39) Fill the cooling system with reusable coolant
and/or new coolant.
(40) Align the hood to the scribe marks. Install the
hood.
(41) Connect the vacuum harness connector.
(a) Firmly push the connectors together ensuring
that the retaining tabs are engaged.
(b) Insert the vacuum connector assembly into
the retaining bracket on the intake manifold.
(42) Install the air cleaner assembly.
(43) Install the battery and connect the battery ca-
ble.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
(44) Start the engine, inspect for leaks and correct
the fluid levels, as necessary.
ENGINE ASSEMBLYÐYJ VEHICLES
REMOVAL
(1) Place a protective cloth over the windshield
frame. Raise the hood and rest it on the windshield
frame (Fig. 17).
(2) Disconnect the battery cables. Remove the bat-
tery.
WARNING: THE COOLANT IN A RECENTLY OPERATED
ENGINE IS HOT AND PRESSURIZED. USE CARE TO
PREVENT SCALDING BY HOT COOLANT. CAREFULLY
RELEASE THE PRESSURE BEFORE REMOVING THE
RADIATOR DRAIN COCK AND CAP.
(3) Remove the radiator drain cock and radiator
cap to drain the coolant. DO NOT waste reusablecoolant. If the solution is clean, drain the coolant into
a clean container for reuse.
(4) Disconnect the wire connectors from the gener-
ator.
(5) Disconnect the ignition coil and distributor wire
connectors.
(6) Disconnect the oil pressure sender wire connec-
tor.
(7) Disconnect the wires at the starter motor sole-
noid and injection wire harness connector.
(8) Perform the Fuel System Pressure Release pro-
cedure (refer to Group 14, Fuel System).
(9) Disconnect the quick-connect fuel lines at the
fuel rail and return line by squeezing the retaining
tabs against the fuel tube (Fig. 18). Pull the fuel tube
and retainer from the quick-connect fitting (refer to
Group 14, Fuel System for the proper procedure).
(10) Remove the fuel line bracket from the intake
manifold.
(11) Disconnect the engine ground strap.
(12) Remove the air cleaner (Fig. 18).
(13) Disconnect the vacuum purge hose at the fuel
vapor canister tee.
(14) Disconnect the idle speed actuator wire con-
nector.
(15) Disconnect the throttle cable and remove it
from the bracket (Fig. 18).
(16) Disconnect the throttle rod at the bellcrank.
(17) Disconnect the speed control cable, if equipped
(Fig. 18).
Fig. 17 Hood on Windshield Frame
9 - 62 4.0L ENGINEJ

(18) Disconnect the oxygen sensor wire connector.
(19) Remove the upper radiator hose and coolant
recovery hose (Fig. 19).
(20) Disconnect lower radiator hoses at the radia-
tor.
(21) Disconnect the coolant hoses from the rear of
the intake manifold and thermostat housing.
(22) Remove the fan shroud screws.
(23) Remove the radiator attaching bolts.
(24) Remove the radiator and fan shroud (Fig. 19).
Refer to Group 7, Cooling System for the proper pro-
cedure.
(25) Remove the fan and spacer or Tempatrol fan
assembly.
(26) Install a 5/16 X 1/2-inch SAE capscrew
through fan pulley into water pump flange. This will
maintain the pulley and water pump in alignment
when crankshaft is rotated.
(27) Remove the power brake vacuum check valve
from the booster, if equipped.
(28) If equipped with power steering (Fig. 19):
(a) Disconnect the hoses from the fittings at the
steering gear.
(b) Drain the pump reservoir.
(c) Cap the fittings on the hoses and steering
gear to prevent foreign objects from entering the
system.
(29) Lift the vehicle and support it with support
stands.
(30) Remove the starter motor.
(31) Remove the flywheel housing access cover.
(32) Remove the engine support cushion-to-bracket
through bolts.
(33) Disconnect the exhaust pipe from the mani-
fold.
(34) Remove the upper flywheel housing bolts and
loosen the bottom bolts.
(35) Lower the vehicle.
(36) Attach a lifting device to the engine.(37) Raise the engine off the front supports.
(38) Place a support stand under the flywheel
housing.
(39) Remove the remaining flywheel housing bolts.
(40) Lift the engine out of the engine compartment
and install on an engine stand.
INSTALLATION
(1) Lift the engine off the stand and lower it into
the engine compartment. For easier installation, it
may be useful to remove the engine support cushions
from the engine support brackets as an aide for
alignment of the engine-to-transmission.
(2) Insert the transmission shaft into the clutch
spline.
(3) Align the flywheel housing with the engine.
(4) Install and finger tighten the flywheel housing
lower bolts.
(5) Install the engine support cushions (if re-
moved).
(6) Remove the support stand from beneath the
flywheel housing.
(7) Lower the engine and engine support cushions
onto the engine compartment brackets. Ensure that
the bolt holes are aligned. Install the bolts and
tighten the nuts.
(8) Remove the engine lifting device.
(9) Raise the vehicle.
(10) Attach the exhaust pipe to the manifold. In-
stall and tighten the nuts to 31 Nzm (23 ft. lbs.)
torque.
(11) Install the flywheel housing access cover.
(12) Install the remaining flywheel housing bolts.
Tighten the bolts to 38 Nzm (28 ft. lbs.) torque.
(13) Install the starter motor and connect the ca-
ble. Tighten the bolts to 45 Nzm (33 ft. lbs.) torque.
(14) Lower the vehicle.
(15) Connect the coolant hoses and tighten the
clamps.
Fig. 18 Fuel Line Quick-Connect Couplings, Air
Cleaner Assembly, Throttle & Speed Control CablesFig. 19 Upper Radiator Hose, Coolant Recovery
Hose, Fan Shroud & Power Steering Pump
J4.0L ENGINE 9 - 63

(16) Remove the pulley-to-water pump flange
alignment capscrew and install the fan and spacer or
Tempatrol fan assembly.
(17) Tighten the serpentine drive belt according to
the specifications listed in Group 7, Cooling System.
(18) Install the fan shroud and radiator (refer to
Group 7, Cooling System for the proper procedure).
(19) Connect the radiator hoses.
(20) Connect the throttle valve rod and retainer.
(21) Connect the throttle cable and install the rod.
(22) Install the throttle valve rod spring.
(23) Connect the speed control cable, if equipped.
(24) Connect the oxygen sensor wire connector.
(25) Install the vacuum hose and check valve on
the brake booster.
(26) Connect the coolant temperature sensor wire
connector.
(27) Connect the idle speed actuator wire connec-
tor.
(28) Connect the fuel inlet and return hoses at the
fuel rail. Verify that the quick-connect fitting assem-
bly fits securely over the fuel lines by giving the fuel
lines a firm tug.
(29) Install the fuel line bracket to the intake man-
ifold.
(30) Connect all fuel injection wire connections.
(31) Install the engine ground strap.
(32) Connect the ignition coil wire connector.
(33) Remove the coolant temperature sending unit
to permit air to escape from the block. Fill the cool-
ing system with coolant. Install the coolant tempera-
ture sending unit when the system is filled.
(34) If equipped with power steering:
(a) Remove the protective caps
(b) Connect the hoses to the fittings at the steer-
ing gear. Tighten the nut to 52 Nzm (38 ft. lbs.)
torque.
(c) Fill the pump reservoir with fluid.
(35) Install the battery and connect the battery ca-
bles.
(36) Install the air cleaner bonnet to the throttle
body.
(37) Install the air cleaner.
(38) Lower the hood and secure in place.
(39) Start the engine and inspect for leaks.
(40) Stop the engine and check the fluid levels.
Add fluid, as required.
ENGINE CYLINDER HEAD COVER
A cured gasket is part of the engine cylinder head
cover.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Disconnect the Crankcase Ventilation (CCV)
vacuum hose from engine cylinder head cover (Fig.
1).(3) Disconnect the fresh air inlet hose from the en-
gine cylinder head cover (Fig. 1).
(4) Remove the engine cylinder head cover mount-
ing bolts.
(5) Remove the engine cylinder head cover.
CLEANING
Remove any original sealer from the cover sealing
surface of the engine cylinder head and clean the
surface using a fabric cleaner.
Remove all residue from the sealing surface using
a clean, dry cloth.
INSPECTION
Inspect the engine cylinder head cover for cracks.
Replace the cover, if cracked.
The original dark grey gasket material should NOT
be removed. If sections of the gasket material are
missing or are compressed, replace the engine cylin-
der head cover. However, sections with minor damage
such as small cracks, cuts or chips may be repaired
with a hand held applicator. The new material must
be smoothed over to maintain gasket height. Allow
the gasket material to cure prior to engine cylinder
head cover installation.
INSTALLATION
(1) If a replacement cover is installed, transfer the
CCV valve grommet and oil filler cap from the origi-
nal cover to the replacement cover.
(2) Install engine cylinder head cover. Tighten the
mounting bolts to 13 Nzm (115 in. lbs.) torque.
(3) Connect the CCV hoses (Fig. 1).
(4) Connect negative cable to battery.
Fig. 1 Engine Cylinder Head Cover
9 - 64 4.0L ENGINEJ

VALVE COMPONENT REPLACEÐCYLINDER HEAD
NOT REMOVED
ROCKER ARMS AND PUSH RODS
This procedure can be done with the engine in or
out of the vehicle.
REMOVAL
(1) Remove the engine cylinder head cover.
(2) Remove the capscrews at each bridge and pivot
assembly (Fig. 2). Alternately loosen the capscrews
one turn at a time to avoid damaging the bridges.
(3) Check for rocker arm bridges which are causing
misalignment of the rocker arm to valve tip area.
(4) Remove the bridges, pivots and corresponding
pairs of rocker arms (Fig. 2). Place them on a bench
in the same order as removed.
(5) Remove the push rods and place them on a
bench in the same order as removed.
CLEANING
Clean all the components with cleaning solvent.
Use compressed air to blow out the oil passages in
the rocker arms and push rods.
INSPECTION
Inspect the pivot surface area of each rocker arm.
Replace any that are scuffed, pitted, cracked or ex-
cessively worn.
Inspect the valve stem tip contact surface of each
rocker arm and replace any rocker arm that is deeply
pitted.
Inspect each push rod end for excessive wear and
replace as required. If any push rod is excessivelyworn because of lack of oil, replace it and inspect the
corresponding hydraulic tappet for excessive wear.
Inspect the push rods for straightness by rolling
them on a flat surface or by shining a light between
the push rod and the flat surface.
A wear pattern along the length of the push rod is
not normal. Inspect the engine cylinder head for ob-
struction if this condition exists.
INSTALLATION
(1) Lubricate the ball ends of the push rods with
Mopar Engine Oil Supplement, or equivalent and in-
stall push rods in their original locations. Ensure
that the bottom end of each push rod is centered in
the tappet plunger cap seat.
(2) Using Mopar Engine Oil Supplement, or equiv-
alent, lubricate the area of the rocker arm that the
pivot contacts. Install rocker arms, pivots and bridge
above each cylinder in their originally position.
(3) Loosely install the capscrews through each
bridge.
(4) At each bridge, tighten the capscrews alter-
nately, one turn at a time, to avoid damaging the
bridge. Tighten the capscrews to 28 Nzm (21 ft. lbs.)
torque.
(5) Install the engine cylinder head cover.
VALVE STEM SEAL AND SPRING REPLACEMENT
This procedure can be done with the engine cylin-
der head installed on the block.
REMOVAL
Each valve spring is held in place by a retainer and
a set of conical valve locks. The locks can be removed
only by compressing the valve spring.
(1) Remove the engine cylinder head cover.
(2) Remove capscrews, bridge and pivot assemblies
and rocker arms for access to each valve spring to be
removed.
(3) Remove push rods. Retain the push rods,
bridges, pivots and rocker arms in the same order
and position as removed.
(4) Inspect the springs and retainer for cracks and
possible signs of weakening.
(5) Remove the spark plug(s) adjacent to the cylin-
der(s) below the valve springs to be removed.
(6) Connect an air hose to the adapter and apply
air pressure slowly. Maintain at least 621 kPa (90
psi) of air pressure in the cylinder to hold the valves
against their seats. For vehicles equipped with an air
conditioner, use a flexible air adaptor when servicing
the No.1 cylinder.
(7) Tap the retainer or tip with a rawhide hammer
to loosen the lock from the retainer. Use Valve Spring
Compressor Tool MD-998772A to compress the spring
and remove the locks (Fig. 3).
(8) Remove valve spring and retainer (Fig. 3).
Fig. 2 Rocker Arm Assembly
J4.0L ENGINE 9 - 65

(9) Remove valve stem oil seals (Fig. 3). Note the
valve seals are different for intake and exhaust
valves. The top of each seal is marked either INT (In-
take) or EXH (Exhaust). DO NOT mix the seals.
INSPECTION
Inspect the valve stems, especially the grooves. An
Arkansas smooth stone should be used to remove
nicks and high spots.
INSTALLATION
CAUTION: Install oil seals carefully to prevent dam-
age from the sharp edges of the valve spring lock
grove.
(1) Lightly push the valve seal over the valve stem
and valve guide boss. Be sure the seal is completely
seated on the valve guide boss.
(2) Install valve spring and retainer.
(3) Compress the valve spring with Valve Spring
Compressor Tool MD-998772A and insert the valve
locks. Release the spring tension and remove the
tool. Tap the spring from side-to-side to ensure that
the spring is seated properly on the engine cylinder
head.
(4) Disconnect the air hose. Remove the adaptor
from the spark plug hole and install the spark plug.
(5) Repeat the procedures for each remaining valve
spring to be removed.
(6) Install the push rods. Ensure the bottom end of
each rod is centered in the plunger cap seat of the
hydraulic valve tappet.
(7) Install the rocker arms, pivots and bridge at
their original location.(8) Tighten the bridge capscrews alternately, one
at a time, to avoid damaging the bridge. Tighten the
capscrews to 28 Nzm (21 ft. lbs.) torque.
(9) Install the engine cylinder head cover.
HYDRAULIC TAPPETS
Retain all the components in the same order as re-
moved.
REMOVAL
(1) Remove the engine cylinder head cover.
(2) Remove the bridge and pivot assemblies and
rocker arms by removing the capscrews at each
bridge. Alternately loosen each capscrew, one turn at
a time, to avoid damaging the bridges.
(3) Remove the push rods.
(4) Remove the tappets through the push rod open-
ings in the cylinder block with Hydraulic Valve Tap-
pet Removal/Installation Tool C-4129-A (Fig. 4).
CLEANING
Clean each tappet assembly in cleaning solvent to
remove all varnish, gum and sludge deposits.
INSPECTION
Inspect for indications of scuffing on the side and
base of each tappet body.
Inspect each tappet base for concave wear with a
straightedge positioned across the base. If the base is
concave, the corresponding lobe on the camshaft is
also worn. Replace the camshaft and defective tap-
pets.
Fig. 3 Valve and Valve Components
Fig. 4 Hydraulic Valve Tappet RemovalÐInstallation
Tool C-4129-A
9 - 66 4.0L ENGINEJ

LEAK-DOWN TEST
After cleaning and inspection, test each tappet for
specified leak-down rate tolerance to ensure zero-lash
operation (Fig. 5).
Swing the weighted arm of the hydraulic valve tap-
pet tester away from the ram of the Leak-Down
Tester.
(1) Place a 7.925-7.950 mm (0.312-0.313 inch) di-
ameter ball bearing on the plunger cap of the tappet.
(2) Lift the ram and position the tappet (with the
ball bearing) inside the tester cup.
(3) Lower the ram, then adjust the nose of the ram
until it contacts the ball bearing. DO NOT tighten
the hex nut on the ram.
(4) Fill the tester cup with hydraulic valve tappet
test oil until the tappet is completely submerged.
(5) Swing the weighted arm onto the push rod and
pump the tappet plunger up and down to remove air.
When the air bubbles cease, swing the weighted arm
away and allow the plunger to rise to the normal po-
sition.
(6) Adjust the nose of the ram to align the pointer
with the SET mark on the scale of the tester and
tighten the hex nut.
(7) Slowly swing the weighted arm onto the push
rod.
(8) Rotate the cup by turning the handle at the
base of the tester clockwise one revolution every 2
seconds.
(9) Observe the leak-down time interval from the
instant the pointer aligns with the START mark on
the scale until the pointer aligns with the 0.125
mark. A normally functioning tappet will require 20-
110 seconds to leak-down. Discard tappets with leak-
down time interval not within this specification.
INSTALLATION
It is not necessary to charge the tappets with en-
gine oil. They will charge themselves within a very
short period of engine operation.(1) Dip each tappet in Mopar Engine Oil Supple-
ment, or equivalent.
(2) Use Hydraulic Valve Tappet Removal/Installa-
tion Tool C-4129-A to install each tappet in the same
bore from where it was originally removed.
(3) Install the push rods in their original locations.
(4) Install the rocker arms and bridge and pivot
assemblies at their original locations. Loosely install
the capscrews at each bridge.
(5) Tighten the capscrews alternately, one turn at
a time, to avoid damaging the bridges. Tighten the
capscrews to 28 Nzm (21 ft. lbs.) torque.
(6) Pour the remaining Mopar Engine Oil Supple-
ment, or equivalent over the entire valve actuating
assembly. The Mopar Engine Oil Supplement, or
equivalent must remain with the engine oil for at
least 1 609 km (1,000 miles). The oil supplement
need not be drained until the next scheduled oil
change.
(7) Install the engine cylinder head cover.
ENGINE CYLINDER HEAD
This procedure can be done with the engine in or
out of the vehicle.
REMOVAL
(1) Disconnect negative cable from battery.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAIN COCK WITH THE SYSTEM HOT AND PRES-
SURIZED BECAUSE SERIOUS BURNS FROM THE
COOLANT CAN OCCUR.
(2) Drain the coolant and disconnect the hoses at
the engine thermostat housing. DO NOT waste reus-
able coolant. If the solution is clean and is being
drained only to service the engine or cooling system,
drain the coolant into a clean container for reuse.
(3) Remove the air cleaner assembly.
(4) Remove the engine cylinder head cover.
(5) Remove the capscrews, bridge and pivot assem-
blies and rocker arms (Fig. 2).
(6) Remove the push rods (Fig. 2).Retain the
push rods, bridges, pivots and rocker arms in
the same order as removed.
(7) Loosen the serpentine drive belt at the power
steering pump, if equipped or at the idler pulley (re-
fer to Group 7, Cooling System for the proper proce-
dure).
(8) If equipped with air conditioning, perform the
following:
(a) Remove the bolts from the A/C compressor
mounting bracket and set the compressor aside.
(b) Remove the air conditioner compressor
bracket bolts from the engine cylinder head.
(c) Loosen the through bolt at the bottom of the
bracket.
Fig. 5 Leak-Down Tester
J4.0L ENGINE 9 - 67

(9) If equipped, disconnect the power steering
pump bracket. Set the pump and bracket aside. DO
NOT disconnect the hoses.
(10) Perform the Fuel System Pressure Release
procedure (refer to Group 14, Fuel System).
(11) Remove the fuel lines and vacuum advance
hose.
(12) Remove the intake and engine exhaust mani-
folds from the engine cylinder head (refer to Group
11, Exhaust System and Intake Manifold for the
proper procedures).
(13) Disconnect the ignition wires and remove the
spark plugs.
(14) Disconnect the temperature sending unit wire
connector.
(15) Remove the ignition coil and bracket assem-
bly.
(16) Remove the engine cylinder head bolts. Bolt
No.14 cannot be removed until the head is moved for-
ward (Fig. 6). Pull bolt No.14 out as far as it will go
and then suspend the bolt in this position (tape
around the bolt).
(17) Remove the engine cylinder head and gasket
(Fig. 6).
(18) If this was the first time the bolts were re-
moved, put a paint dab on the top of the bolt. If the
bolts have a paint dab on the top of the bolt or it
isn't known if they were used before, discard the
bolts.
(19) Stuff clean lint free shop towels into the cylin-
der bores.
CLEANING
Thoroughly clean the engine cylinder head and cyl-
inder block mating surfaces. Clean the intake and
engine exhaust manifold and engine cylinder head
mating surfaces. Remove all gasket material and car-
bon.
Check to ensure that no coolant or foreign material
has fallen into the tappet bore area.Remove the carbon deposits from the combustion
chambers and top of the pistons.
INSPECTION
Use a straightedge and feeler gauge to check the
flatness of the engine cylinder head and block mating
surfaces.
INSTALLATION
The engine cylinder head gasket is a composition
gasket. The gasket is to be installed DRY.DO NOT
use a gasket sealing compound on the gasket.
If the engine cylinder head is to be replaced and
the original valves used, measure the valve stem di-
ameter. Only standard size valves can be used with a
service replacement engine cylinder head unless the
replacement head valve stem guide bores are reamed
to accommodate oversize valve stems. Remove all
carbon buildup and reface the valves.
(1) Remove the shop towels from the cylinder
bores. Coat the bores with clean engine oil.
(2) Position the engine cylinder head gasket (with
the numbers facing up) onto the cylinder block.
CAUTION: Engine cylinder head bolts should be re-
used only once. Replace the head bolts if they were
used before or if they have a paint dab on the top
of the bolt.
(3) With bolt No.14 held in place (tape around
bolt), install the engine cylinder head. Remove the
tape from bolt No.14.
(4) Coat the threads of stud bolt No.11 with Loctite
592 sealant, or equivalent.
(5) Tighten the engine cylinder head bolts in se-
quence according to the following procedure (Fig. 7):
(a) Tighten all bolts in sequence (1 through 14)
to 30 Nzm (22 ft. lbs.) torque.
(b) Tighten all bolts in sequence (1 through 14)
to 61 Nzm (45 ft. lbs.) torque.
(c) Check all bolts to verify they are set to 61
Nzm (45 ft. lbs.) torque.
(d) Tighten bolts (in sequence):
²Bolts 1 through 10 to 149 Nzm (110 ft. lbs.) torque.
²Bolt 11 to 13 Nzm (100 ft. lbs.) torque.
²Bolts 12 through 14 to 149 Nzm (110 ft. lbs.)
torque.
CAUTION: During the final tightening sequence,
bolt No.11 will be tightened to a lower torque than
the rest of the bolts. DO NOT overtighten bolt
No.11.
(e) Check all bolts in sequence to verify the cor-
rect torque.
(f) If not already done, clean and mark each bolt
with a dab of paint after tightening. Should you en-
Fig. 6 Engine Cylinder Head Assembly
9 - 68 4.0L ENGINEJ

counter bolts which were painted in an earlier ser-
vice operation, replace them.
(6) Install the ignition coil and bracket assembly.
(7) Connect the temperature sending unit wire
connector.
(8) Install the spark plugs and tighten to 37 Nzm
(27 ft. lbs.) torque. Connect the ignition wires.
(9) Install the intake and engine exhaust mani-
folds (refer to Group 11, Exhaust System and Intake
Manifold for the proper procedures).
(10) Install the fuel lines and the vacuum advance
hose.
(11) If equipped, attach the power steering pump
and bracket.
(12) Install the push rods, rocker arms, pivots and
bridges in the order they were removed (refer to
Rocker Arms and Push Rods in this section).
(13) Install the engine cylinder head cover.
(14) Attach the air conditioner compressor mount-
ing bracket to the engine cylinder head and block.
Tighten the bolts to 40 Nzm (30 ft. lbs.) torque.
(15) Attach the air conditioning compressor to the
bracket. Tighten the bolts to 27 Nzm (20 ft. lbs.)
torque.
CAUTION: The serpentine drive belt must be routed
correctly. Incorrect routing can cause the water
pump to turn in the opposite direction causing the
engine to overheat.
(16) Install the serpentine drive belt and correctly
tension the belt (refer to Group 7, Cooling System for
the proper procedure).
(17) Install the air cleaner and ducting.
(18) Install the engine cylinder head cover.
(19) Connect the hoses to the engine thermostat
housing and fill the cooling system to the specified
level (refer to Group 7, Cooling Systems for the
proper procedure).
(20) The automatic transmission throttle linkage
and cable must be adjusted after completing the en-
gine cylinder head installation (refer to Group 21,
Transmissions for the proper procedures).(21) Install the temperature sending unit and con-
nect the wire connector.
(22) Connect the fuel line.
(23) Connect negative cable to battery.
(24) Connect the upper radiator hose and heater
hose at the engine thermostat housing.
(25) Fill the cooling system. Check for leaks.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN DIRECT
LINE WITH THE FAN. DO NOT PUT HANDS NEAR
THE PULLEYS, BELTS OR FAN. DO NOT WEAR
LOOSE CLOTHING.
(26) Operate the engine with the radiator cap off.
Inspect for leaks and continue operating the engine
until the engine thermostat opens. Add coolant, if re-
quired.
VALVES AND VALVE SPRINGS
This procedure is done with the engine cylinder
head removed from the block.
REMOVAL
(1) Remove the engine cylinder head from the cyl-
inder block.
(2) Use Valve Spring Compressor Tool
MD-998772A and compress each valve spring.
(3) Remove the valve locks, retainers, springs and
valve stem oil seals. Discard the oil seals.
(4) Use an Arkansas smooth stone or a jewelers
file to remove any burrs on the top of the valve stem,
especially around the groove for the locks.
(5) Remove the valves, and place them in a rack in
the same order as removed.
VALVE CLEANING
Clean all carbon deposits from the combustion
chambers, valve ports, valve stems, valve stem
guides and head.
Clean all grime and gasket material from the en-
gine cylinder head machined gasket surface.
INSPECTION
Inspect for cracks in the combustion chambers and
valve ports.
Inspect for cracks on the exhaust seat.
Inspect for cracks in the gasket surface at each
coolant passage.
Inspect valves for burned, cracked or warped
heads.
Inspect for scuffed or bent valve stems.
Replace valves displaying any damage.
VALVE REFACING
(1) Use a valve refacing machine to reface the in-
take and exhaust valves to the specified angle.
Fig. 7 Engine Cylinder Head Bolt Tightening
Sequence
J4.0L ENGINE 9 - 69

(2) After refacing, a margin of at least 0.787 mm
(0.031 inch) must remain (Fig. 8). If the margin is
less than 0.787 mm (0.031 inch), the valve must be
replaced.
VALVE SEAT REFACING
(1) Install a pilot of the correct size in the valve
guide bore. Reface the valve seat to the specified an-
gle with a good dressing stone. Remove only enough
metal to provide a smooth finish.
(2) Use tapered stones to obtain the specified seat
width when required.
(3) Control valve seat runout to a maximum of
0.0635 mm (0.0025 in.) (Fig. 9).
VALVE STEM OIL SEAL REPLACEMENT
Valve stem oil seals are installed on each valve
stem to prevent rocker arm lubricating oil from en-
tering the combustion chamber through the valve
guide bores. One seal is marked INT (intake valve)
and the other is marked EXH (exhaust valve).
Replace the oil seals whenever valve service is per-
formed or if the seals have deteriorated.
VALVE GUIDES
The valve guides are an integral part of the engine
cylinder head and are not replaceable.
When the valve stem guide clearance is excessive,
the valve guide bores must be reamed oversize. Ser-
vice valves with oversize stems are available in 0.076
mm (0.003 inch) and 0.381 mm (0.015 inch) incre-
ments.
Corresponding oversize valve stem seals are also
available and must be used with valves having 0.381
mm (0.015 inch) oversize stems.
If the valve guides are reamed oversize, the
valve seats must be ground to ensure that the
valve seat is concentric to the valve guide.
VALVE STEM-TO-GUIDE CLEARANCE
MEASUREMENT
Valve stem-to-guide clearance may be measured by
either of the following two methods.
PREFERRED METHOD:
(1) Remove the valve from the head.
(2) Clean the valve stem guide bore with solvent
and a bristle brush.
(3) Insert a telescoping gauge into the valve stem
guide bore approximately 9.525 mm (.375 inch) from
the valve spring side of the head (Fig. 10).
(4) Remove and measure telescoping gauge with a
micrometer.
(5) Repeat the measurement with contacts length-
wise to engine cylinder head.
(6) Compare the crosswise to lengthwise measure-
ments to determine out-of-roundness. If the measure-
Fig. 10 Measurement of Valve Guide Bore Diameter
Fig. 8 Valve Facing Margin
Fig. 9 Measurement of Valve Seat Runout
9 - 70 4.0L ENGINEJ

ments differ by more than 0.0635 mm (0.0025 in.),
ream the guide bore to accommodate an oversize
valve stem.
(7) Compare the measured valve guide bore diam-
eter with specifications (7.95-7.97 mm or 0.313-0.314
inch). If the measurement differs from specification
by more than 0.076 mm (0.003 inch), ream the guide
bore to accommodate an oversize valve stem.
ALTERNATIVE METHOD:
(1) Use a dial indicator to measure the lateral
movement of the valve stem (stem-to-guide clear-
ance). This must be done with the valve installed in
its guide and just off the valve seat (Fig. 11).
(2) Correct clearance is 0.025-0.0762 mm (0.001-
0.003 inch). If indicated movement exceeds the spec-
ification ream the valve guide to accommodate an
oversize valve stem.
Valve seats must be ground after reaming the
valve guides to ensure that the valve seat is
concentric to the valve guide.
VALVE SPRING TENSION TEST
Use a universal Valve Spring Tester and a torque
wrench to test each valve spring for the specified ten-
sion value (Fig. 12).
Replace valve springs that are not within specifica-
tions.
INSTALLATION
(1) Thoroughly clean the valve stems and the valve
guide bores.
(2) Lightly lubricate the stem.
(3) Install the valve in the original valve guide
bore.
(4) Install the replacement valve stem oil seals on
the valve stems. If the 0.381 mm (0.015 inch) over-
size valve stems are used, oversize oil seals are re-
quired.(5) Position the valve spring and retainer on the
engine cylinder head and compress the valve spring
with Valve Spring Compressor Tool MD-998772A.
(6) Install the valve locks and release the tool.
(7) Tap the valve spring from side to side with a
hammer to ensure that the spring is properly seated
at the engine cylinder head. Also tap the top of the
retainer to seat the valve locks.
(8) Install the engine cylinder head.
VALVE TIMING
Disconnect the spark plug wires and remove the
spark plugs.
Remove the engine cylinder head cover.
Remove the capscrews, bridge and pivot assembly,
and rocker arms from above the No.1 cylinder.
Alternately loosen each capscrew, one turn at a
time, to avoid damaging the bridge.
Rotate the crankshaft until the No.6 piston is at
top dead center (TDC) on the compression stroke.
Rotate the crankshaft counterclockwise (viewed
from the front of the engine) 90É.
Install a dial indicator on the end of the No.1 cyl-
inder intake valve push rod. Use rubber tubing to se-
cure the indicator stem on the push rod.
Set the dial indicator pointer at zero.
Rotate the crankshaft clockwise (viewed from the
front of the engine) until the dial indicator pointer
indicates 0.305 mm (0.012 inch) travel distance (lift).
The timing notch index on the vibration damper
should be aligned with the TDC mark on the timing
degree scale.
If the timing notch is more than 13 mm (1/2 inch)
away from the TDC mark in either direction, the
valve timing is incorrect.
If the valve timing is incorrect, the cause may be a
broken camshaft pin. It is not necessary to replace
the camshaft because of pin failure. A spring pin is
available for service replacement.
Fig. 11 Measurement of Lateral Movement of Valve
Stem
Fig. 12 Valve Spring Tester
J4.0L ENGINE 9 - 71