
CYLINDER HEAD
CLEANING
Thoroughly clean the engine cylinder head and cyl-
inder block mating surfaces. Clean the intake and
exhaust manifold and engine cylinder head mating
surfaces. Remove all gasket material and carbon.
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 (Fig. 70).
Minimum cylinder head thickness 89.95mm (3.541
in.)
CAUTION: If only one cylinder head is found to be
distorted and requires machining, it will also be
necessary to machine the remaining cylinders
heads and end plates by a corresponding amount
to maintain correct cylinder alignment.
VALVE GUIDE HEIGHT
(1) Valve Guides height requirement.
(2) Measurement A (Fig. 71): 13.50 - 14.00 mm.
VALVE STEM-TO-GUIDE CLEARANCE
MEASUREMENT
(1) Measure and record internal diameter of valve
guides. Valve guide internal diameter is 8.0 to 8.015
mm (.3149 to .3155 in.).
(2) Measure valve stems and record diameters.
Intake valve stem diameter 7.94 to 7.96 mm (.3125 to
.3133 in). Exhaust valve stem diameter 7.92 to 7.94
mm (.3118 to .31215 in).
(3) Subtract diameter of valve stem from internal
diameter of its respective valve guide to obtain valve
stem clearance in valve guide. Clearance of inlet
valve stem in valve guide is .040 to .075 mm (.0015
to .0029 in). Clearance of exhaust valve stem in valve
guide is .060 to .095 mm (.0023 to .0037 in).
(4) If valve stem clearance in valve guide exceeds
tolerances, new valve guides must be installed.
TIMING GEAR COVER
Be sure mating surfaces of timing gear cover and
cylinder block are clean and free from burrs.
Fig. 69 Rocker Arm Components
Fig. 70 Checking Cylinder Head Flatness
Fig. 71 Valve Guide Height
NS/GSENGINE 9 - 75
CLEANING AND INSPECTION (Continued)

VALVES AND VALVE SPRINGS
VALVE CLEANING
Clean all carbon deposits from the combustion
chambers, valve ports, valve stems, valve stem
guides and heads.
Clean all grime and gasket material from the
engine cylinder head machined gasket surfaces.
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.
Check valve spring height. (Fig. 72).
HYDRAULIC TAPPETS
(1) Clean all tappet parts in a solvent that will
remove all varnish and carbon.
(2) Replace tappets that are unfit for further ser-
vice with new assemblies.
(3) If plunger shows signs of scoring or wear,
install a new tappet assembly. If valve is pitted, or
valve seat on end of plunger is prevented from seat-
ing, install a new tappet assembly.
OIL PUMP
CLEANING
Wash all parts in a suitable solvent and inspect
carefully for damage or wear (Fig. 74).
INSPECTION
(1) Before installing oil pump check pump bore
depth in block (A) and pump body height (B) (Fig.
73). Difference between A and B should be
0.020-0.082 mm.
(2) Check clearance between rotors (Fig. 75).
PISTON AND CONNECTING ROD
PISTONS
(1) Piston Diameter: Size Group A: 91.93-91.94mm
(3.6191-3.6196 in.) Size Group B: 91.94-91.95mm
Fig. 72 Valve Spring Chart
Fig. 73 Oil Pump Bore Depth
Fig. 74 Oil Pump Inner and Outer Rotors
9 - 76 ENGINENS/GS
CLEANING AND INSPECTION (Continued)

(3) If internal diameter of original bearing is being
checked and figures are not within specifications,
new bearings must be used.
(4) Check crankshaft main bearing journals to
bearing clearances. Clearances of main bearings is
.03 to .088mm (.0011 to .0035 in.).
OIL PAN
Remove all gasket material from cylinder block. Be
careful not gouge pan sealing surface.
CYLINDER LINER
INSPECTION
The cylinder walls should be checked for out-of-
round and taper with dail bore gauge. The cylinder
bore out-of-round is 0.100 mm (.0039 inch) maximum
and cylinder bore taper is 0.100 mm (0.0039 inch)
maximum. If the cylinder walls are badly scuffed or
scored, new liners should be installed and honed, and
new pistons and rings fitted.
Measure the cylinder bore at three levels in direc-
tions A and B (Fig. 79). Top measurement should be
10 mm (3/8 inch) down and bottom measurement
should be 10 mm ( 3/8 inch.) up from bottom of bore.
SPECIFICATIONS
2.5L VM DIESEL
DESCRIPTION...........SPECIFICATIONS
Type ......................425CLIEE (36B)
Number of Cylinder......................4
Bore..............................92mm
Stroke............................94mm
Capacity.......................2499.5 cm3
Injection Order.....................1-3-4-2
Compression Ratio...............21:1 (60.5)
Crankshaft
Front Journal Diameter....................
Nominal.................62.985±63.000 mm
±0.25....................62.735±62.750 mm
±0.125...................62.860±62.875 mm
Front Bearing Diameter....................
Nominal.................63.043±63.088 mm
±0.25....................62.793±62.838 mm
±0.125...................62.918±62.963 mm
Clearance Between Journal and Bearing:
0.043±0.103 mm..........................
Center Journal Diameter...................
Fig. 77 Piston, Connecting Rod and Pin
Fig. 78 Bearing Clearance
Fig. 79 Liner Inspection
9 - 78 ENGINENS/GS
CLEANING AND INSPECTION (Continued)

DESCRIPTION...........SPECIFICATIONS
Valve Face Angle
Intake.......................55É30'± 55É50'
Exhaust.....................45É25'± 45É35'
Valve Head Diameter
Intake.....................40.05±40.25 mm
Exhaust.....................33.8±34.0 mm
Valve Head Stand Down
Intake.......................1.08±1.34 mm
Exhaust.....................1.99±1.25 mm
Valve Stem Diameter
Intake.....................7.940±7.960 mm
Exhaust....................7.922±7.940 mm
Valve Clearance in Guide
Intake.....................0.040±0.075 mm
Exhaust....................0.060±0.093 mm
Valve Guide
Inside Diameter...............8.0±8.015 mm
Fitted Height.................13.5±14.0 mm
Valve Spring
Free Length.....................44.65 mm
Fitted Length.....................38.6 mm
Load at Fitted Length............3466% Kg
Load at Top of Lift.............92.564% Kg
Number of Coils............5.33 Valve Timing
Oil Pressure
at 4000 rpm.....3.0to4.5bar(Oil at 90±100ÉC)
Pressure Relief Valve Opens..........6.38 bar
Pressure Relief Valve±Free Length.....57.5 mm
Oil Pump
Outer Rotor End Float..........0.03±0.09 mm
Inner Rotor End Float..........0.03±0.09 mm
Outer Rotor to Body Diameter
Clearance..................0.130±0.230 mm
Rotor Body to Drive Gear Clearance (Pump Not
Fitted)......................3.27±3.73 mm
TORQUE
DESCRIPTION...................TORQUE
Generator Mounting Bracket
Bolts....................47N´m(35ft.lbs.)
Camshaft Thrust Plate Retaining Bolts
Bolt.....................24N´m(18ft.lbs.)
Cylinder Head
Bolts . . See Cylinder Head Installation Procedure
Connecting Rod
Bolts...........29.5 N´m +60É (22 ft. lbs. +60É)
Crankshaft Bearing Carrier
Bolts....................44N´m(32ft.lbs.)
Crankshaft damper (Pulley)
Nut ...................441N´m(325 ft. lbs.)
EGR Valve to Intake Manifold
Tube ....................26N´m(19ft.lbs.)DESCRIPTION...................TORQUE
EGR Tube to EGR Valve
Bolts....................26N´m(19ft.lbs.)
Engine MountÐFront
Support Bracket Engine Bolts . 68 N´m (50 ft. lbs.)
Support Bracket Transmission
Bolts...................101N´m(75ft.lbs.)
Support Cushion Crossmember
Bolts....................54N´m(40ft.lbs.)
Support Cushion Thru Bolt . . . 65 N´m (48 ft. lbs.)
Engine MountÐRear
Support Bracket Transmission
Bolts...................101N´m(75ft.lbs.)
Support Bracket to Engine
Bracket.................101N´m(75ft.lbs.)
Support Cushion Thru Bolt . . . 68 N´m (50 ft. lbs.)
Engine MountÐLeft
Transmission Mounting Bolts . 54 N´m (40 ft. lbs.)
Support Cushion Thru Bolt . . . 71 N´m (53 ft. lbs.)
Engine MountÐRight
Mount to Frame Rail Bolts . . . 68 N´m (50 ft. lbs.)
Mount Bolt (Horizontal) . . . 145 N´m (107 ft. lbs.)
Mount Bolt (Vertical).......101N´m(75ft.lbs.)
Right Engine Mount Bracket
Bolts....................40N´m(30ft.lbs.)
Exhaust Pipe to Turbocharger
Bolts...................28N´m(250 in. lbs.)
Exhaust Manifold Outlet to Turbo
Nuts....................32N´m(24ft.lbs.)
Exhaust Elbow to Turbo
Bolts....................30N´m(22ft.lbs.)
Exhaust Manifold Mounting
Nuts....................30N´m(22ft.lbs.)
Flywheel
Bolts.....SeeRear Crankshaft Seal Installation
Procedure
Engine Adaptor Plate
Bolts....................47N´m(35ft.lbs.)
Front Timing Gear Cover
Bolts....................11N´m(96in.lbs.)
Fuel Filter
Nuts...................28N´m(250 in. lbs.)
Glow Plugs
Plugs..................14N´m(120 in. lbs.)
Idler Pulley Pump Support Bracket
Nuts...................26N´m(228 in. lbs.)
Idler Pulleys (left handed threads)
Bolts....................47N´m(35ft.lbs.)
Injector Pump fuel lines
Nuts..................17.6 N´m (156 in. lbs.)
Injector Pump Gear
Lock Nut..........................86N´m
Injector Pump Mounting
Nuts..................27.5 N´m (240 in. lbs.)
9 - 80 ENGINENS/GS
SPECIFICATIONS (Continued)

DESCRIPTION...................TORQUE
Injector
Tighten to................65N´m(48ft.lbs.)
Intake Manifold Mounting
Nuts...................30N´m(264 in. lbs.)
Main Bearing Oil Delivery Union
Bolts....................54N´m(40ft.lbs.)
Oil Feed Line To Rocker Arms
Bolts.................12.7 N´m (108 in. lbs.)
Oil Feed Line to Block
Bolts.................12.7 N´m (108 in. lbs.)
Oil Feel Line to Vacuum Pump
Bolts.................16.7 N´m (145 in. lbs.)
Oil Filter
Tighten to...............9.8N´m(85in.lbs.)
Oil Filter Adaptor
Fastener.................49N´m(36ft.lbs.)
Oil Filter Base
Fastener.................49N´m(36ft.lbs.)
Oil Pan Mounting
Bolts...................12N´m(108 in. lbs.)
Oil Pickup Tube
Bolts..................11.3N´m(100 in. lbs.)
Oil Pump Mounting
Bolts.................27.5 N´m (240 in. lbs.)
Oil Pan Drain
Plug.....................54N´m(40ft.lbs.)
Power Steering Pressure Hose
Fastener................28N´m(240 in. lbs.)
Power Steering Pulley
Nut ...................170N´m(125 ft. lbs.)
Rear Crankshaft Bearing Carrier
Bolts..................10.8 N´m (95 in. lbs.)
Rocker Arm Cover
Bolts.................14.7 N´m (132 in. lbs.)
Rocker Arm Mounting
Nuts..................29.4 N´m (264 in. lbs.)
Power Steering Pump Mounting
Nuts..................24.5 N´m (216 in. lbs.)
Turbocharger Mounting
Nuts...................32N´m(288 in. lbs.)
Turbocharger Oil Delivery
Bolt..................27.5 N´m (240 in. lbs.)
Turbocharger Oil Drain
Bolts..................10.8 N´m (95 in. lbs.)
Vacuum Pump Mounting
Bolts..................10.8 N´m (95 in. lbs.)
Water Manifold Mounting
Bolts..................11.8N´m(108 in. lbs.)
Water Pump Pulley
Bolts.................27.5 N´m (240 in. lbs.)SPECIAL TOOLS
2.5L VM DIESEL
Crankshaft Pulley and Gear Remover VM.1000A
Cylinder Liner Puller VM.1001
Crankshaft Bearing Remover/Installer VM.1002
NS/GSENGINE 9 - 81
SPECIFICATIONS (Continued)

Dial Indicator Gauge VM.1013
Flywheel Locking Tool VM.1014
Timing Cover Oil Seal Installer VM.1015
Cylinder Retainers VM.1016
Cylinder Head Bolt Wrench M12 VM.1018
NS/GSENGINE 9 - 83
SPECIAL TOOLS (Continued)

(6) Remove vacuum lines for purge solenoid and
PCV valve at intake manifold (Fig. 7).
(7) Remove vacuum lines for power brake booster
and speed control vacuum reservoir at upper intake
manifold fittings (Fig. 8).
(8) Remove throttle cable and speed control cable
(if equipped) from throttle lever (Fig. 9).
(9) Remove throttle cables from bracket by com-
pressing retaining tabs.
(10) Remove two top bolts from intake manifold to
rear support bracket and spacer (Fig. 10).
(11) Remove upper bolt from intake manifold to
front support bracket (Fig. 11).
(12) Remove dipstick.
(13) Remove dipstick tube.
CAUTION: Moving the dipstick tube will cause dam-
age to the sealer, causing an oil leak. Dipstick tube
must be sealed at cylinder block.
(14) Remove upper intake manifold bolts. Remove
upper intake manifold.CAUTION: Cover intake manifold to prevent foreign
material from entering engine.
Fig. 6 Throttle Body Electrical Connectors
Fig. 7 Vacuum Line Connections
Fig. 8 Vacuum Fitting at Rear of Upper Intake
Manifold
Fig. 9 Throttle Cable Attachment to Throttle Body
Fig. 10 Intake Manifold Rear Support Bracket
NSEXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 5
REMOVAL AND INSTALLATION (Continued)

INSTALLATION
(1) Install new upper intake manifold gasket.
NOTE: Center outboard fastener is a double stud.
(2) Tighten upper intake manifold fasteners start-
ing at center and progressing outward in both direc-
tions. Tighten bolts to 28 N´m (250 in. lbs.). Repeat
this procedures until all fasteners are at specified
torque.
(3) Install dipstick tube. Seal tube to cylinder
block using MopartStud N' Bearing Mount Adhe-
sive. Tighten dipstick tube fastener to 12 N´m (105
in. lbs.)
(4) Install dipstick.
(5) Install upper bolt in intake manifold to front
support bracket (Fig. 11). Torque to 28 N´m (250 in.
lbs.).
(6) Install two top bolts at intake manifold to rear
support bracket making sure bracket to manifold
spacer is in place (Fig. 10). Tighten bolts to 28 N´m
(250 in. lbs.)
(7) Install throttle cables in bracket.
(8) Install throttle cable and speed control cable (if
equipped) to throttle lever.
(9) Install vacuum lines for power brake booster
and speed control vacuum reservoir at upper intake
manifold fittings.
(10) Install vacuum lines for purge solenoid and
PCV valve.
(11) Install electrical connectors for MAP sensor,
throttle position sensor, and idle air control motor.(12) Install air intake tube and resonator box to
throttle body.
(13) Connect negative cable to battery.
INTAKE MANIFOLD LOWERÐ2.4L ENGINE
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
SERVICE VEHICLES IN WELL VENTILATED AREAS
AND AVOID IGNITION SOURCES. NEVER SMOKE
WHILE SERVICING THE VEHICLE
To release fuel pressure, refer to the Fuel Delivery
System Pressure Release section of Group 14 Fuel
System for procedure.
REMOVAL
(1) Perform fuel system pressure release proce-
durebefore attempting any repairs.
(2) Remove upper intake manifold. Refer to proce-
dure in this section.
CAUTION: Cover intake manifold to prevent foreign
material from entering engine.
(3) Disconnect electrical connector from intake air
temperature sensor (Fig. 12).
(4) Remove fuel hose quick connect fitting from
the chassis tube (Fig. 13).Refer to Fuel Hoses,
Clamps and Quick Connect Fittings in the Fuel
Delivery Section of this Group.
WARNING: WRAP A SHOP TOWEL AROUND
HOSES TO CATCH ANY GASOLINE SPILLAGE.
Fig. 11 Intake Manifold Front Support Bracket and
Map Sensor
Fig. 12 Intake Air Temperature Sensor
11 - 6 EXHAUST SYSTEM AND INTAKE MANIFOLDNS
REMOVAL AND INSTALLATION (Continued)