1994 JEEP CHEROKEE Service Repair Manual

ENGINE SPECIFICATIONS (CONT.)
9 - 48 2.5L ENGINEJ

ENGINE SPECIFICATIONS (CONT.)
TORQUE SPECIFICATIONS
J2.5L ENGINE 9 - 49

4.0L ENGINE SERVICE PROCEDURES
INDEX
page page
Camshaft............................... 69
Camshaft Pin Replacement................. 71
Crankshaft Main Bearings.................. 80
Cylinder Block........................... 85
Engine AssemblyÐXJ Vehicles.............. 54
Engine AssemblyÐYJ Vehicles.............. 57
Engine Cylinder Head..................... 60
Engine Cylinder Head Cover................ 59
Engine MountÐRear...................... 52
Engine MountsÐFront..................... 51
General Information....................... 50
Hydraulic Tappets........................ 65
Oil Pan ................................ 72Oil Pump............................... 73
Pistons and Connecting Rods............... 74
Rear Main Oil Seals...................... 84
Rocker Arms............................ 59
Specifications........................... 87
Timing Case Cover....................... 67
Timing Case Cover Oil Seal Replacement...... 67
Timing Chain and Sprockets................ 68
Valve Springs and Oil Seals................ 62
Valve Timing............................ 66
Valves and Valve Springs.................. 63
Vibration Damper........................ 67
GENERAL INFORMATION
The 4.0 Liter (242 CID) six-cylinder engine is an
In-line, lightweight, overhead valve engine (Fig. 1).
This engine is designed for unleaded fuel.
The engine cylinder head has dual quench-type
combustion chambers that create turbulence and fast
burning of the air/fuel mixture. This results in good
fuel economy.
The cylinders are numbered 1 through 6 from front
to rear. The firing order is 1-5-3-6-2-4 (Fig. 2).The crankshaft rotation is clockwise, when viewed
from the front of the engine. The crankshaft rotates
within seven main bearings. The camshaft rotates
within four bearings.
BUILD DATE CODE
The engine Build Date Code is located on a ma-
chined surface on the right side of the cylinder block
between the No.2 and No.3 cylinders (Fig. 3).
The digits of the code identify:
(1) 1st DigitÐThe year (4 = 1994).
(2) 2nd & 3rd DigitsÐThe month (01 - 12).
(3) 4th & 5th DigitsÐThe engine type/fuel system/
compression ratio (MX = A 4.0 Liter (242 CID) 8.7:1
compression ratio engine with a multi-point fuel in-
jection system).
(4) 6th & 7th DigitsÐThe day of engine build (01 -
31).
FOR EXAMPLE:Code * 401MX12 * identifies a
4.0 liter (242 CID) engine with a multi-point fuel in-
jection system, 8.7:1 compression ratio and built on
January 12, 1994.
Fig. 2 Engine Firing Order
Fig. 1 Engine Description
9 - 50 4.0L ENGINEJ

OVERSIZE AND UNDERSIZE COMPONENT
CODES
Some engines may be built with oversize or under-
size components such as:
²Oversize cylinder bores.
²Oversize camshaft bearing bores.
²Undersize crankshaft main bearing journals.
²Undersize connecting rod journals.
These engines are identified by a letter code (Fig.
4) stamped on a boss between the ignition coil and
the distributor (Fig. 5).
ENGINE MOUNTSÐFRONT
The front mounts support the engine at each side.
These supports are made of resilient rubber.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Raise the vehicle.
(3) Support the engine.
(4) Remove the nut from the through bolt (Figs. 6
and 7). DO NOT remove the through bolt.
(5) Remove the retaining bolts/nuts from the sup-
port cushions (Figs. 6 and 7).
(6) Remove the through bolt.
(7) Remove the support cushions.
INSTALLATION
(1) If the engine support bracket was removed, po-
sition the bracket onto the block and install the at-
taching bolts (Figs. 6 and 7). Tighten the engine
support bracket bolts:
²XJ VehiclesÐ61 Nzm (45 ft. lbs.) torque.
²YJ VehiclesÐ62 Nzm (46 ft. lbs.) torque.
(2) ON XJ VEHICLES, if the support cushion
bracket was removed, position the bracket onto the
lower front sill (Fig. 8). Install support cushion
bracket bolts/nuts. Tighten the bolts to 54 Nzm (40 ft.
lbs.) torque. Tighten the nuts to 41 Nzm (30 ft. lbs.)
torque.
(3) Place the support cushion into position on the
support cushion bracket (Figs. 6 and 7). Install and
tighten the bolts/nuts:
²XJ VehiclesÐ41 Nzm (30 ft. lbs.) torque.
²YJ VehiclesÐ52 Nzm (38 ft. lbs.) torque.
Fig. 3 Build Date Code Location
Fig. 4 Oversize and Undersize Component Codes
Fig. 5 Oversize and Undersize Component Code
Location
J4.0L ENGINE 9 - 51

(4) Install the through bolt and the retaining nut
(Figs. 6 and 7). Tighten the through bolt nut:
²XJ VehiclesÐ65 Nzm (48 ft. lbs.) torque.
²YJ VehiclesÐ69 Nzm (51 ft. lbs.) torque.
(5) Remove the engine support.
(6) Lower the vehicle.
(7) Connect negative cable to battery.
ENGINE MOUNTÐREAR
A resilient rubber cushion supports the transmis-
sion at the rear between the transmission extension
housing and the rear support crossmember or skid
plate.
REMOVALÐXJ VEHICLES
(1) Disconnect negative cable from battery.
(2) Raise the vehicle and support the transmission.
(3) Remove the nuts holding the support cushion to
the crossmember (Figs. 9 and 10). Remove the cross-
member.
(4)MANUAL TRANSMISSION (Fig. 9):
(a) Remove the support cushion nuts and remove
the cushion.
(b) Remove the transmission support bracket
bolts and remove the bracket from the transmis-
sion.
(5)AUTOMATIC TRANSMISSION (Fig. 10):
Fig. 6 Front MountsÐXJ Vehicles
Fig. 7 Front MountsÐYJ Vehicles
Fig. 8 Support Cushion BracketÐXJ Vehicles
9 - 52 4.0L ENGINEJ

(a) Remove the support cushion bolts and remove
the cushion and the support bracket from the
transmission (4WD) or from the adaptor bracket
(2WD).
(b) On 2WD vehicles, remove the bolts holding
the transmission support adaptor bracket to the
transmission (Fig. 10). Remove the adaptor
bracket.
INSTALLATIONÐXJ VEHICLES
(1)MANUAL TRANSMISSION:
(a) Install the transmission support bracket to
the transmission. Install the bolts and tighten to
46 Nzm (34 ft. lbs.) torque.
(b) Install the support cushion to the support
bracket. Install the nuts and tighten to 75 Nzm (55
ft. lbs.) torque.
(2)AUTOMATIC TRANSMISSION:
(a) On 2WD vehicles, position the transmission
support adaptor bracket to the transmission. Install
the bolts and tighten to 75 Nzm (55 ft. lbs.) torque.
(b) Position the transmission support bracket
and support cushion to the adaptor bracket (2WD)
or the transmission (4WD). Install the bolts and
tighten to 75 Nzm (55 ft. lbs.) torque.
(3) Position the crossmember onto the support
cushion studs. Install the stud nuts and tighten to 22
Nzm (192 in. lbs) torque.
(4) Install crossmember-to-sill bolts and tighten to
41 Nzm (30 ft. lbs.) torque.
(5) Remove the transmission support.
(6) Lower the vehicle.
(7) Connect negative cable to battery.
REMOVALÐYJ VEHICLES
(1) Disconnect negative cable from battery.
(2) Raise the vehicle and support the transmission.
(3)MANUAL TRANSMISSION (Fig. 11):
(a) Remove the nuts holding the support cushion
and the insulator to the skid plate. Remove the up-
per nut from the insulator stud.
(b) Remove the skid plate bolts and the skid
plate. Remove the insulator stud assembly.
(c) Remove the support cushion nuts. Remove the
support cushion from the torque arm bracket.
(d) Remove the torque arm bracket bolts and re-
move the bracket from the transmission.
(4)AUTOMATIC TRANSMISSION (Fig. 12):
(a) Remove the nuts holding the support cushion
to the skid plate. Remove the skid plate.
(b) Remove the bolts and nuts holding the sup-
port cushion to the torque arm bracket. Remove
the support cushion.
(c) Remove the bolts holding the torque arm
bracket to the transmission. Remove the torque
arm bracket.
INSTALLATIONÐYJ VEHICLES
(1)MANUAL TRANSMISSION:
Fig. 9 Rear MountÐXJ Vehicles (Manual
Transmission)
Fig. 10 Rear MountÐXJ Vehicles (Automatic
Transmission)
J4.0L ENGINE 9 - 53

(a) Position the torque arm bracket to the trans-
mission. Install the bolts and tighten to 54 Nzm (40
ft. lbs.) torque.
(b) Position the support cushion onto the torque
arm bracket. Install the nuts and tighten to 54
Nzm (40 ft. lbs.) torque.
(c) Position the insulator stud assembly and up-
per nut (Fig. 11). Position the skid plate to the
studs of the support cushion and the insulator stud
(Fig. 11). Install the support cushion stud nuts and
tighten to 54 Nzm (40 ft. lbs.) torque. Install the
lower stud nut and tighten the upper and lower in-
sulator stud nuts to 41 Nzm (30 ft. lbs.) torque.
(2)AUTOMATIC TRANSMISSION:
(a) Position the torque arm bracket to the trans-
mission. Install the bolts and tighten to 54 Nzm (40
ft. lbs.) torque.
(b) Position the support cushion onto the torque
arm bracket. Install the bolts/nuts and tighten to
54 Nzm (40 ft. lbs.) torque.
(c) Position the skid plate to the studs of the sup-
port cushion and install the nuts. Tighten the sup-
port cushion stud nuts to 54 Nzm (40 ft. lbs.)
torque.
(3) Install the skid plate bolts to the sill and
tighten to 88 Nzm (65 ft. lbs.) torque.(4) Remove the transmission support.
(5) Lower the vehicle.
(6) Connect negative cable to battery.
ENGINE ASSEMBLYÐXJ VEHICLES
REMOVAL
(1) Disconnect the battery cables. Remove the bat-
tery.
(2) Mark the hinge locations on the hood panel for
alignment reference during installation. Remove the
engine compartment lamp. Remove the hood.
WARNING: THE COOLANT IN A RECENTLY OPER-
ATED 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 usable cool-
ant. If the solution is clean, drain the coolant into a
clean container for reuse.
(4) Remove the lower radiator hose.
(5) Remove the upper radiator hose and coolant re-
covery hose (Fig. 13).
Fig. 11 Rear MountÐYJ Vehicles (Manual
Transmission)Fig. 12 Rear MountÐYJ Vehicles (Automatic
Transmission)
9 - 54 4.0L ENGINEJ

(6) Remove upper radiator support retaining bolts
and remove radiator support.
(7) Remove the fan shroud (Fig. 13) and electric
cooling fan.
(8) Disconnect the transmission fluid cooler tubing
(automatic transmission).
(9) Disconnect radiator fan switch wire connector.
(10)Vehicles with Air Conditioning:
(a) Discharge the A/C condenser.
(b) Remove the service valves and cap the com-
pressor ports.
(11) Remove the radiator or radiator/condenser (if
equipped with A/C).
(12) Remove the fan assembly from the idler pul-
ley.
(13) Disconnect the heater hoses at the engine
thermostat housing and water pump (Figs. 13 and
14).
(14) Disconnect the throttle linkages (Fig. 15).
(15) Disconnect the speed control cable (if
equipped)Ð(Fig. 15).(16) Disconnect the line pressure cable (if equipped
with automatic transmission).
(17) Disconnect injection system wire harness con-
nector at the dash panel.
(18) Disconnect the distributor electrical connec-
tion and the oil pressure switch connector.
(19) Disconnect the quick-connect fuel lines at the
fuel rail and return line by squeezing the two retain-
ing tabs against the fuel tube (Fig. 15). Pull the fuel
tube and retainer from the quick-connect fitting (re-
fer to Group 14, Fuel System for the proper proce-
dure).
(20) Remove the fuel line bracket from the intake
manifold.
(21) Remove the air cleaner assembly (Fig. 16).
(22) Remove the power brake vacuum check valve
from the booster, if equipped.
(23) If equipped with power steering (Fig. 16):
(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.
(24) Identify, tag and disconnect all necessary wire
connectors and vacuum hoses.
(25) Raise and support the vehicle.
(26) Disconnect the wires from the starter motor
solenoid.
(27) Remove the starter motor.
(28) Disconnect the exhaust pipe from the mani-
fold.
Fig. 13 Upper Radiator Hose, Coolant Recovery
Hose, Fan Shroud & Heater hoses
Fig. 14 Heater Hoses (RH Drive Vehicle)
Fig. 15 Accelerator Cable, Speed Control Cable,
Automatic Transmission Control Cable & Quick-
Connect Fuel Lines
J4.0L ENGINE 9 - 55