Page 649 of 1502

ENGINE SPECIFICATIONS (CONT.f
Oil
Pump
Clearance
Over
Rotors
(Max.).....
0.1016
mm (0.004 in)
Cover
Out-of-Flat
(Max.)
0.0381 mm (0.0015 in)
Inner
Rotor
Thickness
(Min.) ...... 20.955 mm (0.825 in)
Outer
Rotor
Clearance
(Max.)
0.3556 mm (0.014 in)
Diameter
(Min.) 62.7126 mm (2.469 in)
Thickness
(Min.) . . ........ 20.955 mm
(0.825 in)
Tip
Clearance
Between
Rotors
(Max).
. 0.2032 mm
(0.008 in)
Oil
Pressure
At
Curb
Idle
Speed*
41.4 kPa
(6 psi)
At
3000 rpm 207-552 kPa
(30-80 psi)
Oil
Pressure
Switch
Actuating
Pressure
(Min.) ... 34.5-48.3 kPa (5-7 psi)
*CAUTION:
If
pressure
is
ZERO
at
curb
idle,
DO
NOT run
engine
at
3,000
rpm.
Oil
Filter
Bypass
Valve
Setting
. 62-103 kPa (9-15 psi)
Pistons
Clearance
at
Top
of
Skirt
0.0127-0.0381 mm
(0.0005-0.0015 in)
Land
Clearance
(Diametrical) 0.635-1.016 mm (0.025-0.040 in)
Piston
Length
86.360 mm (3.40 in)
Piston
Ring
Groove
Depth
Nos.
1 and 2 4.572-4.826 mm (0.180-0.190 in)
No.
3 3.810-4.064 mm (0.150-0.160 in)
Weight
592.6-596.6
grams
(20.90-21.04
oz)
Piston
Pins
Clearance
In
Piston
0.00635-0.01905 mm (0.00025-0.00075 in)
In
Rod
(Interference) 0.0178-0.0356 mm (0.0007-0.0014 in)
Diameter.
24.996-25.001 mm (0.9841-0.9843 in)
End
Play..
NONE
Length
75.946-76.454 mm (2.990-3.010 in)
Piston
Rings
Ring
Gap
Compression
Rings
0.254-0.508 mm (0.010-0.020 in)
Oil
Control
(Steel
Rails)
0.254-1.270 mm (0.010-0.050 in)
Ring
Side
Clearance
Compression
Rings
0.038-0.076 mm
(0.0015-0.0030 in)
Oil
Ring
(Steel
Rails)
0.06-0.21
mm
(0.002-0.008 in)
Ring
Width
Compression
Rings
1.971-1.989 mm
(0.0776-0.0783 in)
Oil
Ring
(Steel
Rails)
3.848-3.975 mm (0.1515-0.1565 in)
Valves
Face
Angle
43.25° - 43.75°
Head
Diameter
Intake
48.666 mm (1.916 in)
Exhaust
41.250 mm (1.624 in)
Length
(Overall)
Intake
124.28-125.92 mm (4.893-4.918 in)
Exhaust
124.64-125.27 mm (4.907-4.932 in)
Lift
(Zero
Lash)
10.973 mm (0.432 in)
Stem
Diameter 7.899-7.925 mm (0.311-0.312 in)
Stem-to-Guide
Clearance
0.0254-0.0762 mm
(0.001-0.003 in)
Max.
Allowable
(Rocking
Method).
. 0.4318 mm (0.017 in)
Guide
Bore
Diameter (Std) 7.950-7.976 mm (0.313-0.314 in)
J9309-32
Page 650 of 1502

ENGINE SPECIFICATIONS
(CONT.)
Valve
Springs
Free
Length (Approx.)
49.962
mm
(1.967
in)
Spring
Tension @ 41.66 mm = 378 N (Valve Closed) (@ 1.64 in = 85 lbs)
Spring
Tension @ 30.89 mm = 890 N (Valve Open) (@ 1.212 in = 200 lbs)
Number of
Coils
6.8
Installed Height. 41.66 mm
(Spring
Seat to Retainer) (1.64 in)
Wire Diameter 4.50 mm (0.177 in) Valve Timing
Exhaust
Valve
Closes
(ATC) 16°
Opens
(BBC) 52°
Duration
248°
Intake
Valve
Closes
(ABC) 50°
Opens
(BTC) . . 10°
Duration
240°
Valve Overlap 26°
J9309-33
OVERSIZE AND UNDERSIZE ENGINE COMPONENT MARKINGS
CONDITION
IDENTIFICATION
LOCATION
OF IDENTIFICATION
CRANKSHAFT
JOURNALS
(UNDERSIZE)
0.0254
mm
(0.001
in.)
RorM
M-2-3 etc. (indicating no. 2 and 3 main bearing
journal)
and/or R-l-4 etc. (indicating no. 1 and 4 connecting rod
journal)
Steel stamped (near notch) on no. 6 crankshaft
counterweight.
HYDRAULIC
TAPPETS
(OVERSIZE)
0.2032
mm
(0.008
in.)
Diamond-shaped
stamp
Top
pad -
front
of engine and
flat
ground on outside surface of each O/S
tappet
bore.
VALVE
STEMS
(OVERSIZE)
0.127 mm
(0.005
in.)
X
Milled pad adjacent to two tapped holes
(3/8 in.) on each end of cylinder head.
J9309-81
Page 651 of 1502

9
- 46 3.9L
ENGINE
TORQUE
SPECIFICATIONS
DESCRIPTION
TORQUE
DESCRIPTION
TORQUE
Adjusting Strap Bolt.....
23
N-m
(200
in. lbs.) Camshaft Bolt
68
N-m (50 ft. lbs.j
Camshaft Thrust
Plate
Bolts
24
N-m
(210
in. lbs.)
Chain Case Cover
Bolts
41
N-m
(30 ft.
lbs.)
Connecting Rod Cap Bolts
61
N*m
(45 ft.
lbs.) Crankshaft Main Bearing Cap
Bolts
115 N-m
(85 ft.
lbs.}
Cylinder Head Bolts
1st Step
. 68
N-m
(50 ft.
lbs.)
2nd Step
.............................................
143 N-m (105 ft. lbs.)
Cylinder Head Cover
Bolts
11 N-m
(95
in. lbs.)
Exhaust ManifoId-to-Cylinder Head Bolts/Nuts
34
N-m
(25 ft.
lbs.)
Front
Insulator Attaching
Bolts
(2WD)...
41
N-m
(30 ft.
lbs.)
Front
Insulator Stud Nuts
102
N-m
(75 ft.
lbs.)
Front
Mount Adaptor-to-Block
Bolts..
41
N-m
(30 ft.
lbs.)
Front
Mount Bracket-to- Crossmember
Bolts
(4WD).
41
N-m
(30 ft.
lbs.)
Generator Mounting Bolt
41
N-m
(30 ft.
lbs.)
Intake
Manifold Bolts Refer to Procedure
in
Service Manual.
Oil Pan Bolts
23
N-m
(200
in.
lbs.)
Oil Pan Drain Plug
34
N-m
(25 ft.
lbs.)
Oil Pump Attaching Bolts
41
N-m
(30 ft. lbs.)
Oil Pump Cover
Bolts
11
N-m
(95
in. lbs.) Rear Insulalor-to-Bracket
Through-Bolt (2WD)
68
N-rn
(50 ft. lbs.)
Rear Insuiator-to-Crossmember Support Bracket Nut (2WDJ
.. 41
N-m
(30 ft.
lbs.
Rear Insulator Mounting Plate-to- Rail Assembly
Nuts (4WD)
......................
41
N-m
(30 ft. lbs.
Rear Support Bracket-to-Crossmember Flange Nuts....
41
N-m
(30 ft.
lbs.
Rear Support Plate-to-lnsulator Mounting
Plate
Bolts
(4WD) 41
N-m
(30
ft. lbs.
Rear Support Plate-to-Transfer
Case
Bolts
41
N-m
(30 ft.
lbs.
Rocker Arm Bolts
23
N-m
(200
in. lbs.
Spark
Plugs.......
41
N-m
(30 ft. lbs.
Sfarfer Counting
Bolts.
68
N-m
(50 ft.
lbs.
Throttle
Body
Bolts
(MPI)
23
N-m
(200
in. lbs.
Torque Converter Drive
Plate
Bolts
31
N-m
(270
in. lbs.
Transfer Case-to-Insulator Mounting
Plate
Nuts..............
204
N-m
(150
ft. lbs.
Transmission
Support Bracket
Bolts
(2WD)
68
N-m
(50 ft.
lbs.
Transmission
Support Spacer
Bolts
(4WD).
68
N-m
(50 ft.
lbs.
Transmission
Support Spacer-to-
Insulator Mounting
Plate
Nuts (4WD)
.... 204
N-m
(150 ft.
lbs.
Vibration Damper
Retainer
Bolt................ 183 N-m (135
ft.
lbs.
Water
Pump-to-Chain Case Cover Bolt...
41
N-m
(30
ft. lbs.)
J9309-S8
Page 652 of 1502

5.2L
ENGINE
9 - 47
S.2L ENGINE
SERVICE
PROCEDURES
INDEX
page
Camshaft
. , . 61
Crankshaft
68
Crankshaft Main Bearings
69
Crankshaft Rear
Oil
Seals
...... ........
70
Cylinder Block ...........................
71
Cylinder Head Cover
. . . . 51
Cylinder Heads
52
Distributor
62
Engine
Assembly
. 50
Engine
Front Mounts
47
Engine
Rear Mount ...............
48
Front Crankshaft
Oil
Seal Replacement
. . 61
GENERAL
INFORMATION
The 5.2 Liter (318 CID) eight-cylinder engine is a
V-Type lightweight, single cam, overhead valve en gine with hydraulic roller tappets (Fig. J).
Engine
Type ....
90° V-8 OHV
Bore
and Stroke .....
99.3
x
84.0 mm
(3.91
x
3.31
in.)
Displacement................
5.2L(318cu.
in.)
Compression
Ratio ....... .
9.1:1
Torque .. 379 N-m (280
ft.
lbs.)
@
3,200
rpm
Firing Order .... 1-8-4-3-6-5-7-2
Lubrication
.......
Pressure
Feed-Full Flow
Filtration
Engine
Oil
Capacity......
4.7L
(5.0 Qts)
with Filter
Cooling System ...... Liquid Cooled-Forced
Circulation
Cooling Capacity..........
16.1L(17.0Qts)
Ramcharger
15.6L
(16.5 Qts)
Cylinder Block
,
Cast
Iron
Crankshaft Nodular Iron
Cylinder Head ..............
Cast
Iron
Combustion Chambers
..
Wedge-High
Swirl Valve Shrouding
Camshaft Nodular Cast Iron
Pistons
Aluminum Alloy
w/Strut
Connecting
Rods...........
Forged
Steel
J9309-41
Fig. 1
Engine
Description
This engine is designed for unleaded fuel.
Engine lubrication system consists of a rotor type
oil pump and a full flow oil filter.
The cylinders are numbered from front to rear; 1?
3,
5, 7 on the left bank and 2, 4, 6, 8 on the right
bank. The firing order is 1-8-4-3-6-5-7-2 (Fig. 2).
The engine serial number is stamped into a ma
chined pad located on the left, front corner of the cyl
inder block. When component part replacement is
necessary, use the engine type and serial number for
reference (Fig. 3).
page
General
Information
.......................
47
Hydraulic Tappets
57
Oil
Pan . 63
Oil Pump
. 64
Piston
/
Connecting
Rod
Assembly
66
Rocker
Arms
51
Specifications—5.2L Engine
73
Timing Chain Cover ................
59
Valve Stem Shield
/
Spring Replacement
56
Valve Timing
. 58
Valves
/
Valve Springs
54
Vibration
Damper
. . 58
J908D-49
Fig.
2 Firing Order
X
M 5.2L T
XXXX
XXXXXXXX
X
~
Last Digit of
Model
Year
M
=
Plant
- M
Mound
Road
S
Saltillo
T
Trenton
K
Toluca
5.2L
=
Engine Displacement
T
=
Usage
-
T Truck
XXXX
=
Month/Day
XXXXXXXX
=
Serial Code
-
Last
8
Digits
of
VIN
No.
J9209-73
Fig.
3
Engine
Identification
Number
ENGINE
FRONT
MOUNTS
REMOVAL
(1) Raise hood and position fan to assure clearance
for radiator top tank and hose.
Page 653 of 1502

9
• 48 5.2L
ENGINE
•
CAUTION;
DO NOT lift the
engine
by the
intake
manifold.
(2) Install an engine lifting fixture.
(3) Raise vehicle on hoist.
(4) Remove nuts from brackets and insulators (Fig.
4).
(5) Raise engine with lifting fixture only far
enough to remove insulators.
SCREW
<£>
SCREW
<1j>
FRONT
LOCATING PIN
" ON LEFT
SIDE
ONLY
USE
FRONT HOLES
FOR
INSULATOR MTG,
2-WHEEL DRIVE TIGHTENING TORQUE
75
FT. LBS. (102 N-m)
65 FT. LBS. (88 N.m)
<£>
30 FT. LBS.
(41
N-m)
NUT
WASHER
BRACKET'
INSULATOR
<
LEFTSIDE
4-WHEEL DRIVE
FRAME SHOWN INSULATOR
BRACKET
(FRONT ENG SUPPORT)
Fig.
4
Engine
Front
Mounts
(6) If necessary, remove the bracket from the block
(Fig. 4).
(7) If necessary, remove the front engine support
bracket (Fig. 4).
INSTALLATION (1) If removed, install the front engine support
bracket. Tighten the bolts to 41 N-m (30 ft. lbs.)
torque.
(2) If removed, position the bracket to the block.
Install the screws and tighten screw A to 102 N-m (75 ft. lbs.) torque. Tighten screw B to 88 N-m (65 ft.
lbs.) torque.
(3) With engine raised slightly, install insulators.
(4) Lower engine with lifting fixture while guiding
insulator studs into attaching holes in crossmember
and brackets (Fig. 4). (5) Tighten attaching insulator nuts to 102 N-m
(75 ft. lbs.) torque. (6) Lower the vehicle.
(7) Remove lifting fixture.
ENGINE REAR
MOUNT
REMOVAL-2WD (1) Raise vehicle on a hoist.
(2) Position a transmission jack under the trans
mission and raise rear of transmission and engine
SLIGHTLY. (3) Remove rear mount through-bolt from frame
crossmember (sport utility) or from the transmission support bracket (Fig. 5). (4) Remove the flange nuts from the crossmember
support bracket (Fig. 5).
(5) Raise rear of transmission enough to provide
insulator to crossmember clearance. Remove the in
sulator flange nuts and remove the insulator (Fig. 5). (6) If necessary, remove the attaching bolts hold
ing the transmission support bracket to the transmis
sion (Fig. 5).
INSTALLATION-2WD (1) If removed, position the transmission support
bracket to the transmission (Fig. 5). Install the at taching bolts and tighten to 68 N-m (50 ft. lbs.)
torque.
(2) Position insulator in transmission support
bracket. Install through-bolt.
(3) Be sure insulator is secured in a LEVEL posi
tion relative to transmission rear support bracket.
Tighten the through-bolt nut to 68 N-m (50 ft. lbs.) torque.
(4) Position the crossmember support bracket onto
the insulator (Fig. 5). Install the flange nut(s) and
tighten to 41 N-m (30 ft. lbs.) torque.
(5) Using the transmission jack, lower the insula
tor and crossmember support bracket onto the cross-
member (Fig. 5).
(6) Tighten the crossmember flange nuts to 41 N-
m (30 ft. lbs.) torque. (7) Remove the transmission jack. (8) Lower the vehicle.
REMOVAL-4WD (1) Raise the vehicle on a hoist.
(2) Remove the skid plate (if equipped) from the
rear crossmember and transmission crossmember (Fig. 6). (3) Position transmission jack under transmission
and raise rear of transmission and engine
SLIGHTLY. (4) AUTOMATIC TRANSMISSION-Remove
the nuts and bolts holding the transmission support spacer to the insulator mounting plate (Fig. 7). Re
move the bolts and nuts holding the engine rear sup
port plate to the insulator mounting plate (Fig. 7).
Page 654 of 1502

•
5.21 ENGINE 9 - 49
TRANSMISSION
SUPPORT
BRACKET
TRANSMISSION
TRANSMISSION SUPPORT BRACKET
INSULATOR
CROSSMEMBER
(SPORT
UTILITY)
J9109-240
l^^^U.TRANSFERJCASE
.
SKIDRATlf
~—l!pW;;^
ni ®p
ATTACHING
BOLTS
1|BS^ID
PLATE|
Fig.
5 Rear
Engine
iSKID PLATE
I
ATTACHING
BOLTS
PU873
Fig.
6
Skid
Plate
(5) MANUAL TRANSMISSION-Remove the
nuts and bolts holding the insulator mounting plate
to the transfer case (Fig. 8).
(6) Remove insulator mounting bolts, spacers,
washers and upper/lower insulators (Figs. 7 and 8).
(7) Remove the insulator mounting plate (Figs. 7
and 8). (8) If necessary, remove the transmission support
spacer (automatic transmission) from the extension
assembly (Fig. 7).
(9) If necessary, remove the engine rear support
bracket (automatic transmission) from the transfer case (Fig. 7).
Supports—2WD
mSYALLATION-4WD
(1) If removed, position the engine rear support
bracket (automatic transmission) to the transfer case (Fig. 7). Install the bolts and tighten to 41 N-m (30
ft. lbs.) torque.
(2) If removed, position the transmission support
spacer (automatic transmission) to the extension as
sembly (Fig. 7). Install the bolts and tighten to 68
Nnn (50 ft. lbs.) torque.
(3) Install insulator mounting plate, mounting
bolts,
spacers, washers and upper/lower insulators to the rail assembly (Figs. 7 and 8). Tighten the mounting bolt nuts to 204 N-m (150 ft. lbs.) torque.
(4) AUTOMATIC TRANSMISSION—Align the
engine rear support plate and the transmission sup
port spacer to the insulator mounting plate (Fig. 7). Lower the engine and transmission onto the insula
tor mounting plate and install the bolts. Tighten the
transmission support spacer nuts to 204 N-m (150 ft. lbs.) torque. Tighten the engine rear support plate to
41 N-m (30 ft. lbs.) torque. (5) MANUAL TRANSMISSION—Align the
transfer case to the insulator mounting plate and lower the engine and transmission. Install the bolts and tighten the nuts (Fig. 8 - nut A) to 204 N-m (150
ft. lbs.) torque. Install the bolts and tighten the nuts (Fig. 8 - nut B) to 41 N-m (30 ft. lbs.) torque. (6) Install the skid plate.
Page 655 of 1502

TRANSFER
CASE
TRANSFER
CASE
ENGINE
REAR
SUPPORT PLATE
EXTENSION
ASSEMBLY
TRANSMISSION
SUPPORT
SPACER
SPACER
UPPER
INSULATOR
INSULATOR
MOUNTING
PLATE
LOWER
INSULATOR
fT^RAIL
J9109-244
Fig,
7 Rear Engine Support—4WD
with
Automatic
Transmission
(7)
Lower the vehicle.
ENGINE
ASSEMBLY
REMOVAL
(1) Scribe hood hinge outlines on hood. Remove the
hood. (2) Remove the battery.
(3) Drain cooling system (refer to Group 7, Cooling
System for the proper procedure). (4) Remove the air cleaner.
(5) Disconnect the radiator and heater hoses. Re
move radiator (refer to Group 7, Cooling System). (6) Set fan shroud aside.
(7)
Remove the vacuum lines.
(8) Remove the distributor cap and wiring.
(9) Disconnect the accelerator linkage.
(10) Remove MPI throttle body.
(11) Disconnect the fuel lines.
(12) Disconnect the starter wires.
(13) Disconnect the oil pressure wire.
(14) Discharge the air conditioning system, if
equipped (refer to Group 24, Heating and Air Condi
tioning for service procedures).
(15) Disconnect the air conditioning hoses.
(16) Disconnect the power steering hoses, if
equipped.
INSULATOR
MOUNTING
PLATE
SPACER
UPPER
L\ f
INSULATOR
NUT®
RAIL
ASSEMBLY
LOWER
INSULATOR
l6ff
RAIL
I
J9109-245
Fig.
8 Rear
Engine
Support—4WD
with
Manual
Transmission
(17) Remove starter motor (refer to Group 8B, Bat
tery/Starter/Generator Service).
(18) Remove the generator (refer to Group 8B, Bat
tery/Starter/Generator Service).
(19) Raise and support the vehicle on a hoist.
(20) Disconnect exhaust pipe at manifold.
(21)
AUTOMATIC TRANSMISSION: (a) Support transmission. This will assure that
the torque converter will remain in proper position in the transmission housing. (b) Remove bell housing bolts and inspection
plate. (c) Attach a C-clamp on front bottom of trans
mission torque converter housing to prevent torque
converter from falling out. (d) Remove torque converter drive plate bolts
from torque converter drive plate. Mark converter and drive plate to aid in assembly.
(22)
MANUAL TRANSMISSION; (a) Support transmission.
(b) Disconnect clutch release mechanism and re
move transmission to clutch housing bolts.
CAUTION:
manifold.
DO
NOT lift the
engine
by the
intake
(23) Install an engine lifting fixture.
(24) Remove engine front mount bolts.
Page 656 of 1502

•
5.2L
ENGINE
9 - 51 (25) Lower the vehicle.
(26) On automatic transmission vehicles, discon
nect the engine from the torque converter drive
plate. On manual transmission vehicles, move engine forward until drive pinion shaft clears the clutch
disc.
Remove engine from engine compartment.
(27) Install engine assembly on engine repair
stand.
INSTALLATION
(1) Remove engine from the repair stand and posi
tion in the engine compartment.
(2) Install an engine support fixture.
(3) Raise and support the vehicle on a hoist.
(4) AUTOMATIC TRANSMISSION: (a) Position the torque converter and drive plate.
Install torque converter drive plate bolts. Tighten
the bolts to 31 N-m (270 in. lbs.) torque.
(b) Install the engine front mounts.
(c) Install bell housing bolts. Tighten the bolts to
41 N-m (30 ft. lbs.) torque.
(d) Remove C-clamp.
(e) Install the inspection plate.
(5) MANUAL TRANSMISSION: (a) Position the drive pinion shaft to the clutch
disc.
(b) Connect the clutch release mechanism and
install the transmission to clutch bolts. Tighten the
bolts to 68 N-m (50 ft. lbs.) torque.
(c) Install the engine front mounts.
(6) Remove transmission support.
(7) Install exhaust pipe to manifold. (8) Lower the vehicle.
(9) Remove engine lifting fixture. (10) Install the generator (refer to Group 8B, Bat
tery/Starter/ Generator Service). (11) Install the starter motor (refer to Group 8B,
Battery/Starter/Generator Service). (12) Connect power steering hoses, if so equipped.
(13) Connect air conditioning hoses.
(14) Evacuate and charge the air conditioning sys
tem, if equipped (refer to Group 24, Heater and Air Conditioning for service procedures).
(15) Using a new gasket, install MPI throttle body.
Tighten the throttle body bolts to 23 N-m (200 in. lbs.) torque. (16) Connect the accelerator linkage.
(17) Connect the starter wires.
(18) Connect the oil pressure wire. (19) Install the distributor cap and wiring.
(20) Connect the vacuum lines.
(21) Connect the fuel lines,
(22) Install the radiator (refer to Group 7, Cooling
System). Connect the radiator hoses and heater
hoses.
(23) Install fan shroud in position.
(24) Fill cooling system (refer to Group 7, Cooling
System for the proper procedure). (25) Install the air cleaner.
(26) Install the battery. (27) Warm engine and adjust.
(28) Install hood and line up with the scribe
marks. (29) Road test vehicle.
CYLIiiER
HEAD
COVER
A steel backed silicon gasket is used with the cyl
inder head cover (Fig. 1). This gasket can be used
again.
CYLINDER HEAD
J9209-105
Fig.
1 Cylinder Head
Cover
Gasket
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Disconnect closed ventilation system and evap
oration control system from cylinder head cover.
(3) Remove cylinder head cover and gasket. The
gasket may be used again.
CLEANING
Clean cylinder head cover gasket surface. Clean head rail, if necessary.
INSPECTION
Inspect cover for distortion and straighten, if nec
essary.
Check the gasket for use in head cover installation.
If damaged, use a new gasket.
INSTALLATION
(1) The cylinder head cover gasket can be used
again. Install the gasket onto the head rail.
(2) Position the cylinder head cover onto the gas
ket. Tighten the bolts to 11 N-m (95 in. lbs.) torque.
(3) Install closed crankcase ventilation system and
evaporation control system.
(4) Connect the negative cable to the battery.
ROCKER ARMS
REMOVAL
(1) Disconnect spark plug wires by pulling on the
boot straight out in line with plug. (2) Remove cylinder head cover and gasket.