DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTION
NOISY VALVES 1. High or low oil level in
crankcase.1. Check and correct engine oil
level.
2. Thin or diluted oil. 2. Change oil to correct viscosity.
3. Thick oil 3. (a) Change engine oil and filter.
(b) Run engine to operating
temperature.
(c) Change engine oil and filter
again.
4. Low oil pressure. 4. Check and correct engine oil
pressure problem.
5. Dirt in hydraulic lifters/lash
adjusters.5. Replace hydraulic lifters/lash
adjusters.
6. Worn rocker arms. 6. Inspect oil supply to rocker arms.
7. Worn hydraulic lifters/lash
adjusters.7. Replace hydraulic lifters/lash
adjusters.
8. Worn valve guides. 8. Replace cylinder head assembly.
9. Excessive runout of valve seats
on valve faces.9. Grind valve seats and valves.
CONNECTING ROD NOISE 1. Insufficient oil supply. 1. Check engine oil level.
2. Low oil pressure. 2. Check engine oil level. Inspect oil
pump relief valve and spring.
3. Thin or diluted oil. 3. Change oil to correct viscosity.
4. Thick oil 4. (a) Change engine oil and filter.
(b) Run engine to operating
temperature.
(c) Change engine oil and filter
again.
5. Excessive bearing clearance. 5. Measure bearings for correct
clearance. Repair as necessary.
6. Connecting rod journal
out-of-round.6. Replace crankshaft or grind
surface.
7. Misaligned connecting rods. 7. Replace bent connecting rods.
9 - 6 ENGINE 2.4LRS
ENGINE 2.4L (Continued)
AIR CLEANER HOUSING
REMOVAL
(1) Disconnect the negative battery cable.
(2) Disconnect the inlet air temperature sensor
(Fig. 12).
(3) Remove the inlet hose to throttle body (Fig. 11).
(4) Remove the bolt for air box at upper radiator
cross member.
(5) Pull air box up and off over the single locating
pin.
(6) Remove air box from vehicle
INSTALLATION
(1) Install air box into vehicle and onto the locat-
ing pin.
(2) Install bolt to hold air box to the upper radia-
tor cross member.
(3) Install the inlet hose to the throttle body.
(4) Connect the inlet air temperature sensor (Fig.
12).
(5) Connect the negative battery cable.
CYLINDER HEAD
DESCRIPTION
The cross flow designed, aluminum cylinder head
contains dual over-head camshafts with four valves
per cylinder (Fig. 13). The valves are arranged in two
in-line banks. The intake valves face toward the
front of the vehicle. The exhaust valves face the dash
panel. The cylinder head incorporates powdered
metal valve guides and seats. The cylinder head is
sealed to the block using a multi-layer steel head
gasket and retaining bolts.Integral oil galleries provide lubrication passages
to the hydraulic lash adjusters, camshafts, and valve
mechanisms.
DIAGNOSIS AND TESTINGÐCYLINDER HEAD
GASKET
A cylinder head gasket leak can be located between
adjacent cylinders or between a cylinder and the
adjacent water jacket.
Possible indications of the cylinder head gasket
leaking between adjacent cylinders are:
²Loss of engine power
²Engine misfiring
²Poor fuel economy
Possible indications of the cylinder head gasket
leaking between a cylinder and an adjacent water
jacket are:
²Engine overheating
²Loss of coolant
²Excessive steam (white smoke) emitting from
exhaust
²Coolant foaming
Fig. 12 IAT Sensor 2.4L
Fig. 13 Cylinder Head and Camshafts
1 - CAMSHAFT BEARING CAPS
2 - PLUG
3 - CAMSHAFT
4 - CYLINDER HEAD
5 - CAMSHAFT OIL SEAL
RSENGINE 2.4L9-25
INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
The valves are made of heat resistant steel. They
have chrome plated stems to prevent scuffing. Viton
rubber valve stem seals are integral with the spring
seats. The valves have three-bead lock keepers to
retain springs and to promote valve rotation.
CLEANING
(1) Clean all valves thoroughly and discard
burned, warped and cracked valves.
VALVE SPRINGS & SEALS
REMOVAL
REMOVAL - CYLINDER HEAD ON
(1) Remove cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(2) Remove camshafts (Refer to 9 - ENGINE/CYL-
INDER HEAD/CAMSHAFT(S) - REMOVAL).
(3) Rotate crankshaft until piston is at TDC on
compression.
(4) With air hose attached to adapter tool installed
in spark plug hole, apply 90-120 psi air pressure.
(5) Using Special Tool MD-998772-A with adapter
6779 (Fig. 33), compress valve springs and remove
valve locks.
(6) Remove valve spring(s).
(7) Remove valve stem seal(s) by a using valve
stem seal tool (Fig. 35).
REMOVAL - CYLINDER HEAD OFF
(1) With cylinder head removed from cylinder
block, compress valve springs using a universal valve
spring compressor.
(2) Remove valve retaining locks, valve spring
retainers, valve stem seals and valve springs.
(3) Before removing valves,remove any burrs
from valve stem lock grooves to prevent dam-
age to the valve guides.Identify valves, locks and
retainers to insure installation in original location.
(4) Inspect the valves. (Refer to 9 - ENGINE/CYL-
INDER HEAD/VALVE SPRINGS - INSPECTION)
INSPECTION
(1) Whenever valves have been removed for inspec-
tion, reconditioning or replacement, valve springs
should be tested for correct tension. Discard the
springs that do not meet specifications. The following
specifications apply to both intake and exhaust
valves springs:
²Valve Closed Nominal TensionÐ76 lbs. @ 38.0
mm (1.50 in.)
²Valve Open Nominal TensionÐ136 lbs. @ 29.75
mm (1.17 in.)
(2) Inspect each valve spring for squareness with a
steel square and surface plate, test springs from both
ends. If the spring is more than 1.5 mm (1/16 inch)
out of square, install a new spring.
INSTALLATION
INSTALLATION - CYLINDER HEAD ON
(1) Install valve seal/valve spring seat assembly
(Fig. 34). Push the assembly down to seat it onto the
valve guide.
(2) Install valve spring and retainer, use Special
Tool MD-998772-A with adapter 6779 to compress
valve springs only enough to install locks (Fig. 33).
Correct alignment of tool is necessary to avoid nick-
ing valve stems.
(3) Remove air hose and install spark plugs.
(4) Install camshafts (Refer to 9 - ENGINE/CYL-
INDER HEAD/CAMSHAFT(S) - INSTALLATION).
(5) Install cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER - INSTALLATION).
INSTALLATION - CYLINDER HEAD OFF
(1) Coat valve stems with clean engine oil and
insert in cylinder head.
(2) Install new valve stem seals on all valves
using a valve stem seal tool (Fig. 35). The valve stem
seals should be pushed firmly and squarely over
valve guide.
Fig. 33 Valve Spring - Removal/Installation
1 - VALVE SPRING COMPRESSOR MD 998772A
2 - AIR HOSE
RSENGINE 2.4L9-33
ENGINE 3.3/3.8L
TABLE OF CONTENTS
page page
ENGINE 3.3/3.8L
DESCRIPTION.........................78
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - INTRODUCTION...........78
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - PERFORMANCE...........80
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - MECHANICAL.............82
DIAGNOSIS AND TESTING - ENGINE OIL
LEAK INSPECTION....................84
DIAGNOSIS AND TESTING - CYLINDER
COMPRESSION PRESSURE TEST........85
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE
TEST...............................85
STANDARD PROCEDURE
STANDARD PROCEDURE - MEASURING
BEARING CLEARANCE USING
PLASTIGAGE........................86
FORM-IN-PLACE GASKETS AND SEALERS . 86
STANDARD PROCEDURE - ENGINE
GASKET SURFACE PREPARATION........87
HYDROSTATIC LOCKED ENGINE.........87
STANDARD PROCEDURE - REPAIR OF
DAMAGED OR WORN THREADS.........88
STANDARD PROCEDURE - ENGINE CORE
AND OIL GALLERY PLUGS..............88
REMOVAL - ENGINE ASSEMBLY...........88
INSTALLATION - ENGINE ASSEMBLY........91
SPECIFICATIONS
3.3/3.8L ENGINE......................93
SPECIFICATIONS - TORQUE............97
SPECIAL TOOLS
3.3/3.8L ENGINE......................98
AIR CLEANER ELEMENT
REMOVAL............................101
INSTALLATION........................101
AIR CLEANER HOUSING
REMOVAL............................101
INSTALLATION........................102
CYLINDER HEAD
DESCRIPTION........................102
DIAGNOSIS AND TESTINGÐCYLINDER HEAD
GASKET...........................102
REMOVAL - CYLINDER HEAD............103
CLEANING...........................103
INSPECTION.........................104
INSTALLATION - CYLINDER HEAD.........104CYLINDER HEAD COVER(S)
DESCRIPTION........................105
CYLINDER HEAD COVER - RIGHT
REMOVAL............................106
INSTALLATION........................106
CYLINDER HEAD COVER - LEFT
REMOVAL............................107
INSTALLATION........................107
INTAKE/EXHAUST VALVES & SEATS
DESCRIPTION........................107
OPERATION..........................107
STANDARD PROCEDURE - REFACING
VALVESANDVALVESEATS ............107
REMOVAL............................108
CLEANING...........................108
INSPECTION.........................108
INSTALLATION........................109
VALVE SPRINGS
DESCRIPTION........................109
OPERATION..........................109
REMOVAL
REMOVAL - CYLINDER HEAD OFF.......109
REMOVAL - CYLINDER HEAD ON........111
INSPECTION..........................111
INSTALLATION
INSTALLATION - CYLINDER HEAD OFF . . . 111
INSTALLATION - CYLINDER HEAD ON....111
ROCKER ARMS
DESCRIPTION
DESCRIPTION - ROCKER ARMS.........112
DESCRIPTION - PUSHRODS............112
OPERATION
OPERATION - ROCKER ARMS..........112
OPERATION - PUSHRODS.............112
REMOVAL - ROCKER ARMS AND SHAFT....112
DISASSEMBLY - ROCKER ARMS
AND SHAFT.........................113
ASSEMBLY - ROCKER ARMS AND SHAFT . . . 113
INSTALLATION - ROCKER ARMS
AND SHAFT.........................113
VALVE STEM SEALS
DESCRIPTION........................114
REMOVAL............................115
INSTALLATION........................115
ENGINE BLOCK
DESCRIPTION........................115
STANDARD PROCEDURE - CYLINDER BORE
HONING............................115
CLEANING...........................115
9 - 76 ENGINE 3.3/3.8LRS
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTION
NOISY VALVES 1. High or low oil level in
crankcase.1. Check and correct engine oil
level.
2. Thin or diluted oil. 2. Change oil to correct viscosity.
3. Thick oil 3. (a) Change engine oil and filter.
(b) Run engine to operating
temperature.
(c) Change engine oil and filter
again.
4. Low oil pressure. 4. Check and correct engine oil
pressure problem.
5. Dirt in hydraulic lifters/lash
adjusters.5. Replace hydraulic lifters/lash
adjusters.
6. Worn rocker arms. 6. Inspect oil supply to rocker arms.
7. Worn hydraulic lifters/lash
adjusters.7. Replace hydraulic lifters/lash
adjusters.
8. Worn valve guides. 8. Replace cylinder head assembly.
9. Excessive runout of valve seats
on valve faces.9. Grind valve seats and valves.
CONNECTING ROD NOISE 1. Insufficient oil supply. 1. Check engine oil level.
2. Low oil pressure. 2. Check engine oil level. Inspect oil
pump relief valve and spring.
3. Thin or diluted oil. 3. Change oil to correct viscosity.
4. Thick oil 4. (a) Change engine oil and filter.
(b) Run engine to operating
temperature.
(c) Change engine oil and filter
again.
5. Excessive bearing clearance. 5. Measure bearings for correct
clearance. Repair as necessary.
6. Connecting rod journal
out-of-round.6. Replace crankshaft or grind
surface.
7. Misaligned connecting rods. 7. Replace bent connecting rods.
9 - 82 ENGINE 3.3/3.8LRS
ENGINE 3.3/3.8L (Continued)
(2) Disconnect the inlet air temperature sensor
(Fig. 16).
(3) Remove the inlet hose to throttle body.
(4) Remove the bolt for air box at upper radiator
cross member.
(5) Pull air box up and off over the single locating
pin.
(6) Remove air box from vehicle
INSTALLATION
(1) Install air box into vehicle and onto the locat-
ing pin.
(2) Install bolt to hold air box to the upper radia-
tor cross member.
(3) Install the inlet hose to the throttle body.
(4) Connect the inlet air temperature sensor (Fig.
16).
(5) Connect the negative battery cable.
CYLINDER HEAD
DESCRIPTION
The aluminum cylinder heads (Fig. 17) are
designed to create high flow combustion chambers to
improve performance, while minimizing the change
to the burn rate in the chamber. The cylinder head
incorporates the combustion chamber. Two valves
per-cylinder are used with inserted valve seats and
guides. A multi-layer steel (MLS) type gasket is used
between the cylinder head and engine block.
DIAGNOSIS AND TESTINGÐCYLINDER HEAD
GASKET
A cylinder head gasket leak can be located between
adjacent cylinders or between a cylinder and the
adjacent water jacket.
Possible indications of the cylinder head gasket
leaking between adjacent cylinders are:
²Loss of engine power
²Engine misfiring
²Poor fuel economy
Possible indications of the cylinder head gasket
leaking between a cylinder and an adjacent water
jacket are:
²Engine overheating
²Loss of coolant
²Excessive steam (white smoke) emitting from
exhaust
²Coolant foaming
CYLINDER-TO-CYLINDER LEAKAGE TEST
To determine if an engine cylinder head gasket is
leaking between adjacent cylinders, follow the proce-
dures in Cylinder Compression Pressure Test (Refer
to 9 - ENGINE - DIAGNOSIS AND TESTING). An
engine cylinder head gasket leaking between adja-
cent cylinders will result in approximately a 50±70%
reduction in compression pressure.
CYLINDER-TO-WATER JACKET LEAKAGE TEST
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING WITH COOLANT PRES-
SURE CAP REMOVED.
VISUAL TEST METHOD
With the engine cool, remove the coolant pressure
cap. Start the engine and allow it to warm up until
thermostat opens.
If a large combustion/compression pressure leak
exists, bubbles will be visible in the coolant.
COOLING SYSTEM TESTER METHOD
WARNING: WITH COOLING SYSTEM TESTER IN
PLACE, PRESSURE WILL BUILD UP FAST. EXCES-
SIVE PRESSURE BUILT UP, BY CONTINUOUS
ENGINE OPERATION, MUST BE RELEASED TO A
SAFE PRESSURE POINT. NEVER PERMIT PRES-
SURE TO EXCEED 138 kPa (20 psi).
Install Cooling System Tester 7700 or equivalent to
pressure cap neck. Start the engine and observe the
tester's pressure gauge. If gauge pulsates with every
power stroke of a cylinder a combustion pressure
leak is evident.
Fig. 16 Inlet Air Temperature Sensor
9 - 102 ENGINE 3.3/3.8LRS
AIR CLEANER HOUSING (Continued)
CHEMICAL TEST METHOD
Combustion leaks into the cooling system can also
be checked by using Bloc-Chek Kit C-3685-A or
equivalent. Perform test following the procedures
supplied with the tool kit.
REMOVAL - CYLINDER HEAD
(1) Drain the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
(2) Disconnect negative cable from battery.
(3) Remove upper and lower intake manifolds.
(Refer to 9 - ENGINE/MANIFOLDS/INTAKE MANI-
FOLD - REMOVAL)
WARNING: INTAKE MANIFOLD GASKET IS MADE
OF VERY THIN METAL AND MAY CAUSE PER-
SONAL INJURY, HANDLE WITH CARE.
(4) Remove the cylinder head covers. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL)
(5) Remove the spark plugs from cylinder head.(6) Remove the dipstick and tube (Fig. 18).
(7) Remove exhaust manifold(s). (Refer to 9 -
ENGINE/MANIFOLDS/EXHAUST MANIFOLD -
REMOVAL)
(8) Remove rocker arm and shaft assemblies.(Refer
to 9 - ENGINE/CYLINDER HEAD/ROCKER ARMS -
REMOVAL) Remove push rods andmark positions
to ensure installation in original locations.
(9) Remove the eight head bolts from each cylinder
head and remove cylinder heads (Fig. 22).
CLEANING
To ensure engine gasket sealing, proper surface
preparation must be performed, especially with the
use of aluminum engine components and multi-layer
steel cylinder head gaskets.
NOTE: Multi-Layer Steel (MLS) head gaskets require
a scratch free sealing surface.
Fig. 17 Cylinder Head and Components
1 - VALVE LOCKS 5 - SPRING SEATS
2 - RETAINERS 6 - CYLINDER HEAD
3 - VALVE SPRINGS 7 - VALVE - EXHAUST
4 - VALVE STEM SEALS 8 - VALVE - INTAKE
RSENGINE 3.3/3.8L9 - 103
CYLINDER HEAD (Continued)
CYLINDER HEAD COVER -
LEFT
REMOVAL
(1) Disconnect spark plug wires from spark plugs.
(2) Disconnect crankcase vent hose from cylinder
head cover.
(3) Remove cylinder head cover bolts.
(4) Remove cylinder head cover and gasket.
INSTALLATION
(1) Clean cylinder head and cover mating surfaces.
Inspect cylinder head cover surface for flatness.
Replace gasket as necessary.
(2) Assemble gasket to cylinder cover by inserting
the fasteners through each bolt hole on cover and
gasket (Fig. 25).
(3) Install the cylinder head cover and bolts (Fig.
26).
(4) Tighten cylinder head cover bolts to 12 N´m
(105 in. lbs.) (Fig. 26).
(5) Connect crankcase vent hose.
(6) Connect spark plug wires to spark plugs.
INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
The valves have chrome plated valve stems with
four-bead lock grooves. The valve stem seals are
made of Viton rubber.
OPERATION
The two valves per cylinder are opened using
hydraulic lifters, push rods, and rocker arms.
STANDARD PROCEDURE - REFACING VALVES
AND VALVE SEATS
The intake and exhaust valves and seats are
machined to specific angles (Fig. 27).
VALVES
(1) Inspect the remaining margin after the valves
are refaced (Fig. 28). (Refer to 9 - ENGINE - SPEC-
IFICATIONS)
VALVE SEATS
CAUTION: Remove metal from valve seat only. Do
not remove material from cylinder head (Fig. 29).
(1) When refacing valve seats, it is important that
the correct size valve guide pilot be used for reseat-
ing stones. A true and complete surface must be
obtained.(2) Measure the concentricity of valve seat using
dial indicator (Fig. 30). Total runout should not
exceed 0.051 mm (0.002 in.) total indicator reading.
(3) Inspect the valve seat using Prussian blue to
determine where the valve contacts the seat. To do
this, coat valve seatLIGHTLYwith Prussian blue
then set valve in place. Rotate the valve with light
pressure. If the blue is transferred to the center of
valve face, contact is satisfactory. If the blue is trans-
ferred to top edge of valve face, lower valve seat with
a 15 degree stone. If the blue is transferred to the
bottom edge of valve face raise valve seat with a 65
degrees stone.
Fig. 27 VALVE FACE AND SEAT
1 - VALVE FACE WIDTH
2 - VALVE FACE ANGLE
3 - SEAT ANGLE
4 - SEAT CONTACT AREA
Fig. 28 Valve Margin
1 - VALVE FACE
2 - VALVE MARGIN
RSENGINE 3.3/3.8L9 - 107