Jeep XJ. Manual — part 307

(18) Lower the vehicle.
(19) Connect the battery negative cable.
(20) Start the engine and check for leaks.

EXHAUST MANIFOLD—4.0L ENGINE

The intake and engine exhaust manifolds on the

4.0L engine must be removed and installed together.
The manifolds use a common gasket at the cylinder
head.

Refer to Intake Manifold—4.0L Engine in this sec-

tion for the proper removal and installation proce-
dures.

CYLINDER HEAD COVER

The cylinder head cover is isolated from the cylin-

der head via grommets and a reusable molded rubber
gasket. The grommet and limiter are retained in the
cylinder head cover.

There are two cylinder head bolts that have a pin

to locate the cylinder head cover gasket, they are
located at position 8 and 9 (Fig. 52)

REMOVAL

(1) Disconnect negative cable from battery.
(2) Disconnect the Crankcase Ventilation (CCV)

vacuum hose from engine cylinder head cover.

(3) Disconnect the fresh air inlet hose from the

engine cylinder head cover.

(4) Disconnect the accelerator, transmission, and

speed (if equipped) control cables from the throttle
body (Fig. 51).

(5) Remove the three bolts that fasten the control

cable bracket to the intake manifold.

(6) Remove control cables from cylinder head cover

clip.

(7) Position control cables and bracket away from

cylinder head cover secure with tie straps.

(8) Remove the engine cylinder head cover mount-

ing bolts.

(9) Remove the engine cylinder head cover and

gasket.

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 cylinder head cover and gasket. Tighten

the mounting bolts to 10 N·m (85 in. lbs.) torque.

(3) Connect the CCV hoses.
(4) Install control cables and bracket on intake

manifold and tighten bolts to 8.7 N·m (77 in. lbs.)
torque.

(5) Connect control cables to throttle body linkage.
(6) Snap control cables into cylinder head cover

clip.

(7) Connect negative cable to battery.

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) Check for rocker arm bridges which are caus-

ing misalignment of the rocker arm to valve tip area.

(3) Remove the capscrews at each bridge and pivot

assembly (Fig. 53). Alternately loosen the capscrews
one turn at a time to avoid damaging the bridges.

(4) Remove the bridges, pivots and corresponding

pairs of rocker arms (Fig. 53). 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.

INSTALLATION

(1) Lubricate the ball ends of the push rods with

Mopar Engine Oil Supplement, or equivalent and
install push rods in their original locations. Ensure

Fig. 51 Engine Cylinder Head Cover

1 – TRANS CONTROL CABLE
2 – ACCELERATOR CABLE
3 – CONTROL CABLE BRACKET
4 – CYLINDER HEAD COVER

Fig. 52 Cylinder Head Cover Gasket Locator Pins at

#8 & #9

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4.0L ENGINE

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REMOVAL AND INSTALLATION (Continued)

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 N·m (21 ft. lbs.)
torque.

(5) Install the engine cylinder head cover.

VALVE SPRINGS AND OIL SEALS

This procedure can be done with the engine cylin-

der head installed on the block.

REMOVAL

Inspect the valve stems, especially the grooves. An

Arkansas smooth stone should be used to remove
nicks and high spots.

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 cap screws, bridge and pivot assem-

blies 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. 54).

(8) Remove valve spring and retainer (Fig. 54).
(9) Remove valve stem oil seals (Fig. 54). Note the

valve seals are different for intake and exhaust
valves. The top of each seal is marked either INT
(intake/black in color) or EXH (exhaust/brown in
color). DO NOT mix the seals.

Fig. 53 Rocker Arm Assembly

1 – CAPSCREWS
2 – BRIDGE
3 – PIVOT ASSEMBLY
4 – PUSH RODS
5 – ROCKER ARMS

Fig. 54 Valve and Valve Components

1 – VALVE LOCKS

(3–BEAD)

2 – RETAINER
3 – VALVE STEM OIL SEAL
4 – INTAKE VALVE
5 – EXHAUST VALVE
6 – VALVE SPRING

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4.0L ENGINE

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REMOVAL AND INSTALLATION (Continued)

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) Release air pressure and 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 cap screws alternately, one

at a time, to avoid damaging the bridge. Tighten the
cap screws to 28 N·m (21 ft. lbs.) torque.

(9) Install the engine cylinder head cover.

CYLINDER HEAD

This procedure can be done with the engine in or

out of the vehicle.

REMOVAL

(1) Disconnect the battery negative cable.

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 and the water pump
inlet. DO NOT waste reusable 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.

(6) Remove the push rods. Retain the push rods,

bridges, pivots and rocker arms in the same
order as removed.

(7) Loosen the accessory drive belt at the power

steering pump. (Refer to Group 7, Cooling System for
the correct procedure). Slip the belt off of the power
steering pulley.

(8) Remove the A/C compressor mounting bolts

and secure the compressor to the side.

(9) Remove the power steering pump and bracket

from the intake manifold and water pump. 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) Disconnect the fuel supply line at the fuel rail.

(Refer to Group 14, Quick-Connect Fittings for the
correct procedures)

(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 coil rail electrical connectors

and remove the coil rail.

(14) Remove spark plugs.
(15) Disconnect the temperature sending unit wire

connector.

(16) Remove the engine cylinder head bolts. Bolt

No.14 cannot be removed until the head is moved for-
ward (Fig. 55). 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. 55).

(18) If this was the first time the bolts were

removed, 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 cyl-

inder bores.

NOTE: If the valves, springs, or seals are to be
inspected/replaced at this time, refer to Valves and
Valve Springs in this section for proper inspection
procedures.

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
diameter. 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.

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4.0L ENGINE

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REMOVAL AND INSTALLATION (Continued)

(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) using the alignment dowels
in the cylinder block, to position the gasket.

CAUTION: Engine cylinder head bolts should be
reused 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 over the same
dowels used to locate the gasket. Remove the tape
from bolt No.14.

(4) Coat the threads of stud bolt No.11 with Loc-

tite 592 sealant, or equivalent.

(5) Tighten the engine cylinder head bolts in

sequence according to the following procedure (Fig.
56).

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.

(a) Tighten all bolts in sequence (1 through 14)

to 30 N·m (22 ft. lbs.) torque.

(b) Tighten all bolts in sequence (1 through 14)

to 61 N·m (45 ft. lbs.) torque.

(c) Check all bolts to verify they are set to 61

N·m (45 ft. lbs.) torque.

(d) Tighten bolts in sequence:

• Bolts 1 through 10 to 149 N·m (110 ft. lbs.)

torque.

• Bolt 11 to 135 N·m (100 ft. lbs.) torque.

• Bolts 12 through 14 to 149 N·m (110 ft. lbs.)

torque.

(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
encounter bolts which were painted in an earlier
service operation, replace them.

(6) Install the spark plugs and tighten to 37 N·m

(27 ft. lbs.) torque.

(7) Connect the temperature sending unit wire

connector.

(8) Install the ignition coil rail and coil rail electri-

cal connectors.

(9) Install the intake and engine exhaust mani-

folds (refer to procedures in this section).

(10) Install the fuel line and the vacuum advance

hose.

(11) 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 N·m (30 ft. lbs.) torque.

(15) Attach the air conditioning compressor to the

bracket. Tighten the bolts to 27 N·m (20 ft. lbs.)
torque.

Fig. 55 Engine Cylinder Head Assembly

1 – CYLINDER HEAD BOLTS
2 – CYLINDER HEAD GASKET
3 – CYLINDER HEAD

CYLINDER HEAD BOLTS

POSITION

DESCRIPTION

1,4,5,12,13

1/2 in.-13 BOLT

8,9

1/2 in.-13 BOLT WITH DOWEL
POINT

2,3,6,7,10,11,14

1/2 in.-13 WITH 7/16 in.-14 STUD
END

All bolts are 12 point drives for rocker cover clearance

Fig. 56 Engine Cylinder Head Bolt Tightening

Sequence

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4.0L ENGINE

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REMOVAL AND INSTALLATION (Continued)