1998 DODGE RAM 1500 Valve cover

þ Loss of engine power
þ Engine misfiring
þ Poor fuel economy
²Possible indications of the cylinder head gasket
leaking between a cylinder and an adjacent water
jacket are:
þ Engine overheating
þ Loss of coolant
þ Excessive steam (white smoke) emitting from
exhaust
þ Coolant 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 in this
section. An engine cylinder head gasket leaking
between adjacent cylinders will result in approxi-
mately 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.
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
(1) Disconnect the battery negative cable.
(2) Drain cooling system.
(3) Remove the air cleaner resonator and duct
work.
(4) Remove the generator.
(5) Remove closed crankcase ventilation system.
(6) Disconnect the evaporation control system.
(7) Perform the Fuel System Pressure Release pro-
cedure (Refer to 14 - FUEL SYSTEM/FUEL DELIV-
ERY - STANDARD PROCEDURE). Disconnect the
fuel supply line (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/QUICK CONNECT FITTING - STAN-
DARD PROCEDURE).
(8) Disconnect heater hoses.
(9) Remove cylinder head covers and gaskets.
(10) Remove intake manifold and throttle body as
an assembly.
(11) Remove rocker arm assemblies and push rods.
Identify to ensure installation in original locations.
(12) Remove the head bolts from each cylinder
head and remove cylinder heads. Discard the cylin-
der head gasket.
CLEANING
Clean all surfaces of cylinder block and cylinder
heads.
Clean cylinder block front and rear gasket surfaces
using a suitable solvent.
INSPECTION
(1) Inspect the cylinder head for out-of-flatness,
using a straightedge and a feeler gauge. If tolerances
exceed 0.0508 mm (0.002 in.) replace the cylinder
head.
(2) Inspect the valve seats for damage. Service the
valve seats as necessary.
(3) Inspect the valve guides for wear, cracks or
looseness. If either condition exist, replace the cylin-
der head.
(4) Inspect pushrods. Replace worn or bent push-
rods.
INSTALLATION
(1) Clean all surfaces of cylinder block and cylin-
der heads.
(2) Clean cylinder block front and rear gasket sur-
faces using a suitable solvent.
CAUTION: The head gaskets are not interchange-
able between left and right sides. They are marked
ªLº and ªRº to indicate left and right sides.
(3) Position new cylinder head gaskets onto the
cylinder block.
9 - 200 ENGINE - 5.7LDR
CYLINDER HEAD (Continued)

REMOVAL
(1) Remove the cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(2) Compress valve springs using Valve Spring
Compressor Tool special tool # C-3422and adapter
8464.
(3) Remove valve retaining locks, valve spring
retainers, valve stem seals and valve springs.
(4) Before removing valves, remove any burrs from
valve stem lock grooves to prevent damage to the
valve guides. Identify valves to ensure installation in
original location.
INSTALLATION
(1) Clean valves thoroughly. Discard burned,
warped and cracked valves.
(2) Remove carbon and varnish deposits from
inside of valve guides with a reliable guide cleaner.
(3) Measure valve stems for wear. If wear exceeds
0.051 mm (0.002 inch), replace the valve.
(4) Coat valve stems with lubrication oil and insert
them in cylinder head.
(5) If valves or seats are reground, check valve
stem height. If valve is too long, replace cylinder
head.
(6) Install new seals on all valve guides. Install
valve springs and valve retainers.
(7) Compress valve springs with Valve Spring
Compressor Tool special tool # C- 3422and adapter
8464, install locks and release tool. If valves and/or
seats are ground, measure the installed height of
springs. Make sure the measurement is taken from
bottom of spring seat in cylinder head to the bottom
surface of spring retainer.
(8) Install cylinder head (Refer to 9 - ENGINE/
CYLINDER HEAD - INSTALLATION).
ROCKER ARM / ADJUSTER
ASSY
REMOVAL
(1) Remove cylinder head cover.(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL)
(2) Loosen the rocker shafts using the following
sequence:Center, center-left, center-right, left,
right,.
CAUTION: The rocker shaft assemblies are not
interchangeable between intake and exhaust. The
intake rocker arms are marked with an ªIº.
(3) Remove the rocker shafts. Note location for
reassembly.CAUTION: The longer push rods are for the exhaust
side, and the shorter push rods are for intake side.
(4) Remove the pushrods. Note pushrod location
for reassembly.
INSTALLATION
CAUTION: The longer push rods are for the exhaust
side, and the shorter push rods are for intake side.
(1) Install the push rods in the same order as
removed.
CAUTION: Verify that pushrod is installed into
rocker arm and lifter correctly while installing
rocker shaft assembly. Recheck after rocker shaft
has been torqued to specification.
CAUTION: The rocker shaft assemblies are not
interchangeable between intake and exhaust. The
intake rocker arms are marked with the letter ªIº.
(2) Install rocker shaft assemblies in the same
order as removed.
CAUTION: Ensure that hold downs and rocker arms
are not overlapped when torquing bolts.
(3) Tighten the rocker shaft bolts to 22 N´m (195
in. lbs.) torque,using the following sequence:Center,
center-right, center-left, right, left.
CAUTION: DO NOT rotate or crank the engine dur-
ing or immediately after rocker arm installation.
Allow the hydraulic roller tappets adequate time to
bleed down (about 5 minutes).
(4) Install cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
VALVE STEM SEALS
DESCRIPTION
The valve guide seals are made of rubber and
incorporate an integral steel valve spring seat. The
integral garter spring maintains consistent lubrica-
tion control to the valve stems.
DRENGINE - 5.7L 9 - 203
INTAKE/EXHAUST VALVES & SEATS (Continued)

VALVE SPRINGS
REMOVAL
(1) Disconnect negative battery cable.
(2) Remove air cleaner assembly.
(3) Remove air intake resonator.
(4) Remove spark plug cables.
(5) Remove ignition coil connectors (Fig. 6).
(6) Remove ignition coils.
(7) Remove one spark plug.
(8) Remove valve cover.
CAUTION: The piston must be at TDC, and both
valves closed on the cylinder to be serviced.
NOTE: If removing intake valve spring, install spe-
cial tool# 9070, pushrod retaining plate, to retain
the intake pushrods.
(9) Remove exhaust/intake rocker arm shafts.
(10) Install spring compressor, special tool# 9065.
NOTE: All valve springs and seals are removed in
the same manner.(11) Charge cylinder with air.
NOTE: Tap the top of the valve spring retainer to
loosen the spring retainers locks.
(12) Compress valve spring and remove valve
retainer locks.
(13) Release spring compressor and remove valve
spring.
NOTE: The valve springs are interchangeable
between intake and exhaust.
(14) Remove valve seal.
INSTALLATION
(1) Install valve seal.
(2) Install valve spring.
(3) Using special tool# 9065, compress valve spring
and install valve spring retainer and locks.
(4) Release air charge in cylinder.
(5) Remove spring compressor tool # 9065.
CAUTION: Verify that the pushrods are fully seated
into lifter and rocker arm. Recheck after rocker arm
shaft has been torqued to specification.
(6) Install rocker arm shaft and pushrods(Refer to
9 - ENGINE/CYLINDER HEAD/ROCKER ARM /
ADJUSTER ASSY - INSTALLATION).
(7) Tighten the rocker shaft bolts to 22 N´m (195
in. lbs.) torque,using the following sequence:Center,
center-right, center-left, right, left.
(8) Remove special tool# 9070, pushrod retaining
plate, if used.
(9) Install cylinder head cover.
(10) Tighten cylinder head cover bolts and double
ended studs(Refer to 9 - ENGINE/CYLINDER
HEAD/CYLINDER HEAD COVER(S) - INSTALLA-
TION).
(11) Install spark plugs.
(12) Install ignition coil on plug, and torque fas-
teners to 12 N´m (105 in. lbs)
(13) Install ignition coil connectors.
(14) Install spark plug cables.
(15) Install air intake resonator.
(16) Install air cleaner assembly.
(17) Connect negative battery cable.
Fig. 6 IGNITION COIL R/I Ð 5.7L V-8
1 - SLIDE LOCK (SLIDE OUTWARD TO UNLOCK)
2 - SPARK PLUG CABLE (TO OPPOSITE CYLINDER BANK
SPARK PLUG)
3 - RELEASE LOCK / TAB (PUSH HERE)
4 - ELEC. CONNECTOR
5 - IGNITION COIL
6 - COIL MOUNTING BOLTS (2)
7 - SPARK PLUG CABLE (TO OPPOSITE CYLINDER BANK
IGNITION COIL)
9 - 204 ENGINE - 5.7LDR

ENGINE BLOCK
CLEANING
Thoroughly clean the oil pan and engine block gas-
ket surfaces.
Use compressed air to clean out:
²The galley at the oil filter adaptor hole.
²The front and rear oil galley holes.
²The feed holes for the crankshaft main bearings.
Once the block has been completely cleaned, apply
Loctite PST pipe sealant with Teflon 592 to the
threads of the front and rear oil galley plugs. Tighten
the 1/4 inch NPT plugs to 20 N´m (177 in. lbs.)
torque. Tighten the 3/8 inch NPT plugs to 27 N´m
(240 in. lbs.) torque.
INSPECTION
(1) It is mandatory to use a dial bore gauge to
measure each cylinder bore diameter. To correctly
select the proper size piston, a cylinder bore gauge,
capable of reading in 0.003 mm (.0001 in.) INCRE-
MENTS is required. If a bore gauge is not available,
do not use an inside micrometer (Fig. 7).
(2) Measure the inside diameter of the cylinder
bore at three levels below top of bore. Start perpen-
dicular (across or at 90 degrees) to the axis of the
crankshaft and then take two additional reading.
(3) Measure the cylinder bore diameter crosswise
to the cylinder block near the top of the bore. Repeatthe measurement near the middle of the bore, then
repeat the measurement near the bottom of the bore.
(4) Determine taper by subtracting the smaller
diameter from the larger diameter.
(5) Rotate measuring device 90É and repeat steps
above.
(6) Determine out-of-roundness by comparing the
difference between each measurement.
(7) If cylinder bore taper does not exceed 0.025
mm (0.001 inch) and out-of-roundness does not
exceed 0.025 mm (0.001 inch), the cylinder bore can
be honed. If the cylinder bore taper or out- of-round
condition exceeds these maximum limits, the cylinder
block must be replaced. A slight amount of taper
always exists in the cylinder bore after the engine
has been in use for a period of time.CAMSHAFT & BEARINGS (IN
BLOCK)
REMOVAL
REMOVAL - CAMSHAFT CORE HOLE PLUG
CAUTION: Do not damage the rear surface of the
camshaft or the core plug sealing surface, when
removing the core plug.
(1) Remove the rear cam bearing core plug.
REMOVAL - CAMSHAFT
(1) Remove the battery negative cable.
(2) Remove the air cleaner assembly.
(3) Drain coolant.
(4) Remove the accessory drive belt.
(5) Remove the generator.
(6) Remove the A/C compressor, and set aside
(7) Remove the radiator (Refer to 7 - COOLING/
ENGINE/RADIATOR - REMOVAL).
(8) Remove intake manifold(Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - REMOVAL).
(9) Remove cylinder head covers(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(10) Remove both left and right cylinder heads(Re-
fer to 9 - ENGINE/CYLINDER HEAD - REMOVAL) .
(11) Remove the oil pan(Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - REMOVAL).
(12) Remove timing case cover(Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(13) Remove the oil pick up tube.
(14) Remove the oil pump(Refer to 9 - ENGINE/
LUBRICATION/OIL PUMP - REMOVAL).
Fig. 7 BORE GAUGE-TYPICAL
1 - FRONT
2 - BORE GAUGE
3 - CYLINDER BORE
4 - 38 MM (1.5 in)
DRENGINE - 5.7L 9 - 205

(15) Remove timing chain(Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - REMOVAL).
(16) Remove camshaft tensioner/thrust plate
assembly.
NOTE: Identify tappets to ensure installation in orig-
inal location.
(17) Remove the retainer assembly and tappets.
(18) Install a long bolt into front of camshaft to aid
in removal of the camshaft. Remove camshaft, being
careful not to damage cam bearings with the cam
lobes.
INSPECTION
(1) The cam bearings are not serviceable. Do not
attempt to replace cam bearings for any reason.
INSTALLATION
INSTALLATION - CAMSHAFT CORE HOLE PLUG
CAUTION: The new core hole plug must be installed
to the proper depth or camshaft damage could
develope. The plug must be installed squarely in
the bore.
(1) Install a new core hole plug at the rear of cam-
shaft, using special tool # 9048. Clean plug and apply
mopartlock and seal adhesive to the edge of the
plug, before installing. The plug must be installed to
a depth of+/-0.25mm from the end of the machined
bevel, that is the end of the bevel that is closest to
the cam bearing.
INSTALLATION - CAMSHAFT
(1) Lubricate camshaft lobes and camshaft bearing
journals and insert the camshaft
(2) Install camshaft Tensioner plate assembly.
Tighten bolts to 28 N´m (250 in. lbs.) torque.
(3) Install timing chain and sprockets(Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT/CHAIN
AND SPROCKETS - INSTALLATION) .
(4) Measure camshaft end play(Refer to 9 -
ENGINE - SPECIFICATIONS). If not within limits
install a new thrust plate.
(5) Install the oil pump(Refer to 9 - ENGINE/LU-
BRICATION/OIL PUMP - INSTALLATION).
(6) Install the oil pick up tube.
(7) Each tappet reused must be installed in the
same position from which it was removed.When
camshaft is replaced, all of the tappets must be
replaced.(8) Install the tappets and retainer assembly(Refer
to 9 - ENGINE/ENGINE BLOCK/HYDRAULIC LIFT-
ERS (CAM IN BLOCK) - INSTALLATION).
(9) Install both left and right cylinder heads(Refer
to 9 - ENGINE/CYLINDER HEAD - INSTALLA-
TION) .
(10) Install pushrods
(11) Install rocker arms(Refer to 9 - ENGINE/CYL-
INDER HEAD/ROCKER ARM / ADJUSTER ASSY -
INSTALLATION).
(12) Install timing case cover(Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(13) Install the oil pan(Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - INSTALLATION).
(14) Install cylinder head covers(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(15) Install intake manifold(Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - INSTALLA-
TION).
(16) Install the A/C compressor, and set aside
(17) Install the generator.
(18) Install the accessory drive belt.
(19) Install the radiator (Refer to 7 - COOLING/
ENGINE/RADIATOR - INSTALLATION).
(20) Install the air cleaner assembly.
(21) Install the battery negative cable.
(22) Refill coolant.
(23) Refill engine oil.
(24) Start engine and check for leaks.
CRANKSHAFT
REMOVAL
(1) Remove the vibration damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).
(2) Remove the oil pan(Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - REMOVAL).
(3) Remove the oil pump pickup.
(4) Remove the windage tray/oil pan gasket.
(5) Remove the timing chain cover(Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(6) Remove the oil pump(Refer to 9 - ENGINE/LU-
BRICATION/OIL PUMP - REMOVAL).
(7) Remove the timing drive(Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - REMOVAL).
(8) Identify rod bearing caps before removal.
Remove rod bearing caps with bearings.
(9) Identify main bearing caps before removal.
Remove main bearing caps and bearings one at a
time.
9 - 206 ENGINE - 5.7LDR
CAMSHAFT & BEARINGS (IN BLOCK) (Continued)

(10) Remove the thrust washers.
(11) Remove the rear oil seal retainer(Refer to 9 -
ENGINE/ENGINE BLOCK/CRANKSHAFT REAR
OIL SEAL RETAINE - REMOVAL).
(12) Remove the crankshaft out of the block.
(13) Remove and discard the crankshaft rear oil
seal.
(14) Remove and discard the front crankshaft oil
seal.
INSTALLATION
(1) Select the proper main bearings(Refer to 9 -
ENGINE/ENGINE BLOCK/CRANKSHAFT MAIN
BEARINGS - STANDARD PROCEDURE) .
(2) Install main bearings in block and caps, and
lubricate bearings.
(3) Position the crankshaft into the cylinder block.
(4) Install the thrust washers.
NOTE: The main cap crossbolts are torqued after
final torque of the main cap bolts. Always use a
new washer/seal on crossbolts.
(5) Clean and oil all cap bolts. Install all main
bearing caps. Install all cap bolts and alternately
tighten in two steps using the following sequence
(Fig. 8).
²Step1±27N´m(20ft. lbs.) torque.
²Step2±Turnmain cap bolts an additional 90É.(6) Install the crossbolts with new washer/gasket.
Starting with crossbolt A (Fig. 8) torque each cross-
bolt to 28 N´m torque.
(7) Repeat crossbolt torque procedure.
(8) Measure crankshaft end play(Refer to 9 -
ENGINE/ENGINE BLOCK/CRANKSHAFT MAIN
BEARINGS - STANDARD PROCEDURE) .
(9) Position the connecting rods onto the crank-
shaft and install the rod bearing caps(Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON & CONNECT-
ING ROD - INSTALLATION).
(10) Install timing drive(Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - INSTALLATION) .
(11) Install oil pump (Refer to 9 - ENGINE/LU-
BRICATION/OIL PUMP - INSTALLATION).
(12) Install the timing chain cover(Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(13) Install the rear main seal and retainer(Refer
to 9 - ENGINE/ENGINE BLOCK/CRANKSHAFT
REAR OIL SEAL RETAINE - INSTALLATION).
(14) Install the windage tray/oil pan gasket.
(15) Install the oil pick up tube.
(16) Install the oil pan(Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - INSTALLATION).
(17) Install the vibration damper(Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
INSTALLATION).
(18) Install the engine(Refer to 9 - ENGINE -
INSTALLATION).
CRANKSHAFT MAIN
BEARINGS
STANDARD PROCEDURE - CRANKSHAFT MAIN
BEARING - FITTING
MAIN BEARING JOURNAL DIAMETER
(CRANKSHAFT REMOVED)
Crankshaft removed from the cylinder block.
Clean the oil off the main bearing journal.
Determine the maximum diameter of the journal
with a micrometer. Measure at two locations 90É
apart at each end of the journal.
The maximum allowable taper is 0.008mm (0.0004
inch.) and maximum out of round is 0.005mm (0.0002
inch). Compare the measured diameter with the jour-
nal diameter specification (Main Bearing Fitting
Chart). Select inserts required to obtain the specified
bearing-to-journal clearance.
CRANKSHAFT MAIN BEARING SELECTION
The main bearings are ªselect fitº to achieve proper
oil clearances. For main bearing selection, the crank-
Fig. 8 MAINCAP TIGHTENING SEQUENCE
1 - Stud Location
DRENGINE - 5.7L 9 - 207
CRANKSHAFT (Continued)

INSTALLATION
(1) Throughly clean all gasket resdue from the
engine block.
(2) Use extream care and clean all gasket resdue
from the retainer.
(3) Position the gasket onto the retainer.
(4) Position the retainer onto the engine block.
(5) Install the retainer mounting bolts. Tighten the
bolts to 15 N´m (132 in. lbs.) using a crisscross pat-
tern, starting with the bolt on the lower right.
(6) Install a new rear seal(Refer to 9 - ENGINE/
ENGINE BLOCK/CRANKSHAFT OIL SEAL - REAR
- INSTALLATION).
(7) Install the oil pan (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - INSTALLATION).
(8) Install the drive plate / flywheel.
(9) Install the transmission.
(10) Check and verify engine oil level.
(11) Start engine and check for leaks.
FLEX PLATE
REMOVAL
(1) Remove the transmission.
(2) Remove the bolts and flexplate.
INSTALLATION
(1) Position the flexplate or flywheel onto the
crankshaft and install the bolts hand tight.
(2)For automatic transmissions:Tighten the
flexplate retaining bolts to 95 N´m (70 ft. lbs.).
(3)For manual transmissions:Tighten the fly-
wheel retaining bolts to 75 N´m (55 ft. lbs.).
(4) Install the transmission.
HYDRAULIC TAPPETS
DIAGNOSIS AND TESTING - HYDRAULIC
TAPPETS
Before disassembling any part of the engine to cor-
rect tappet noise, check the oil pressure. If vehicle
has no oil pressure gauge, install a reliable gauge at
the pressure sending-unit. The pressure should be
between 207-552 kPa (30-70 psi) at 3,000 RPM.
Check the oil level after the engine reaches normal
operating temperature. Allow 5 minutes to stabilize
oil level, check dipstick. The oil level in the pan
should never be above the FULL mark or below the
ADD OIL mark on dipstick. Either of these two con-
ditions could be responsible for noisy tappets.
OIL LEVEL
HIGH
If oil level is above the FULL mark, it is possible
for the connecting rods to dip into the oil. With the
engine running, this condition could create foam in
the oil pan. Foam in oil pan would be fed to the
hydraulic tappets by the oil pump causing them to
lose length and allow valves to seat noisily.
LOW
Low oil level may allow oil pump to take in air. When
air is fed to the tappets, they lose length, which allows
valves to seat noisily. Any leaks on intake side of oil
pump through which air can be drawn will create the
same tappet action. Check the lubrication system from
the intake strainer to the pump cover, including the
relief valve retainer cap. When tappet noise is due to
aeration, it may be intermittent or constant, and usu-
ally more than one tappet will be noisy. When oil level
and leaks have been corrected, operate the engine at
fast idle. Run engine for a sufficient time to allow all of
the air inside the tappets to be bled out.
TAPPET NOISE DIAGNOSIS
(1) To determine source of tappet noise, operate
engine at idle with cylinder head covers removed.
(2) Feel each valve spring or rocker arm to detect
noisy tappet. The noisy tappet will cause the affected
spring and/or rocker arm to vibrate or feel rough in
operation.
NOTE: Worn valve guides or cocked springs are
sometimes mistaken for noisy tappets. If such is
the case, noise may be dampened by applying side
thrust on the valve spring. If noise is not apprecia-
bly reduced, it can be assumed the noise is in the
tappet. Inspect the rocker arm push rod sockets
and push rod ends for wear.
(3)
Valve tappet noise ranges from light noise to a
heavy click. A light noise is usually caused by excessive
leak-down around the unit plunger, or by the plunger
partially sticking in the tappet body cylinder. The tap-
pet should be replaced. A heavy click is caused by a tap-
pet check valve not seating, or by foreign particles
wedged between the plunger and the tappet body. This
will cause the plunger to stick in the down position.
This heavy click will be accompanied by excessive clear-
ance between the valve stem and rocker arm as valve
closes. In either case, tappet assembly should be
removed for inspection and cleaning.
(4) The valve train generates a noise very much
like a light tappet noise during normal operation.
Care must be taken to ensure that tappets are mak-
ing the noise. If more than one tappet seems to be
noisy, it's probably not the tappets.
9 - 210 ENGINE - 5.7LDR
CRANKSHAFT REAR OIL SEAL RETAINER (Continued)

REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Remove the air cleaner(Refer to 9 - ENGINE/
AIR INTAKE SYSTEM - REMOVAL).
(3) Remove intake manifold(Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - REMOVAL).
(4) Remove cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(5) Remove rocker arm assembly and push rod-
s(Refer to 9 - ENGINE/CYLINDER HEAD/ROCKER
ARM / ADJUSTER ASSY - REMOVAL). Identify
push rods to ensure installation in original location.
(6) Remove the cylinder head(Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(7) Remove bolt from tappet guide holder.
(8) Remove tappet guide holder.
(9) Pull tappet out of bore with a twisting motion.
If all tappets are to be removed and reused, identify
tappets to ensure installation in original location.
(10) Check camshaft lobes for abnormal wear.
INSTALLATION
(1) Lubricate tappets.
(2) Install tappets in their original positions.
(3)
Install tappet guide holder. Install the tappet
guide holder bolt and tighten to 12 N´m (106 in. lbs.)
torque.
(4) Install cylinder head(Refer to 9 - ENGINE/
CYLINDER HEAD - INSTALLATION).
(5) Install pushrods and rocker arm assembly(Re-
fer to 9 - ENGINE/CYLINDER HEAD/ROCKER
ARM / ADJUSTER ASSY - INSTALLATION).
(6) Install cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(7)
Install intake manifold(Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - INSTALLATION).
(8) Install the air cleaner(Refer to 9 - ENGINE/
AIR INTAKE SYSTEM - INSTALLATION).
(9) Connect the negative cable to the battery.
CAUTION: To prevent damage to valve mechanism,
engine must not be run above fast idle until all
hydraulic tappets have filled with oil and have
become quiet.
(10) Road test vehicle and check for leaks.
PISTON & CONNECTING ROD
DESCRIPTION
CAUTION: Do not use a metal stamp to mark con-
necting rods as damage may result, instead use ink
or a scratch awl.The pistons are made of a high strength aluminum
alloy. Piston skirts are coated with a solid lubricant
(Molykote) to reduce friction and provide scuff resis-
tance. The piston top ring groove and land is anod-
ized. The connecting rods are made of forged
powdered metal, with a ªfractured capº design. A
pressed fit piston pin is used to attach the piston and
connecting rod.
STANDARD PROCEDUREÐPISTON FITTING
(1) To correctly select the proper size piston, a cyl-
inder bore gauge, capable of reading in 0.003 mm (
.0001 in.) INCREMENTS is required. If a bore gauge
is not available, do not use an inside micrometer.
(2) Measure the inside diameter of the cylinder
bore at a point 38.0 mm (1.5 inches) below top of
bore. Start perpendicular (across or at 90 degrees) to
the axis of the crankshaft at point A and then take
an additional bore reading 90 degrees to that at point
B (Fig. 11).
(3) The coated pistons will be serviced with the
piston pin and connecting rod pre-assembled. The
piston-rod assembly is specific for the left cylinder
bank ( odd numbered) and the right cylinder bank (
even numbered) and must not be interchanged.
(4) The coating material is applied to the piston
after the final piston machining process. Measuring
the outside diameter of a coated piston will not pro-
vide accurate results (Fig. 10). Therefore measuring
the inside diameter of the cylinder bore with a dial
Bore Gauge isMANDATORY. To correctly select the
proper size piston, a cylinder bore gauge capable of
reading in 0.003 mm (.0001 in.) increments is
required.
Fig. 10 MOLY COATED PISTON
1 - MOLY COATED
2 - MOLY COATED
DRENGINE - 5.7L 9 - 211
HYDRAULIC TAPPETS (Continued)