spark plugs replace DODGE NEON 2000 Service Repair Manual

30,000 Miles (48 000 km) or at 24 months
²Change the engine oil.
²Replace the engine oil filter.
²Lubricate the front suspension lower ball joint.
²Inspect the tie rod ends and boot seals.
²Adjust the drive belt tension.
²Replace the engine air cleaner element (fil-
ter).
²Replace the engine spark plugs
²Change the automatic transaxle fluid.
37,500 Miles (60 000 km) or at 30 months
²Change the engine oil.
²Replace the engine oil filter.
45,000 Miles (72 000 km) or at 36 months
²Change the engine oil.
²Replace the engine oil filter.
²Inspect the front brake pads and rear brake lin-
ings.
²Adjust the drive belt tension.
²Flush and replace the engine coolant at 36
months, regardless of mileage.
52,500 Miles (84 000 km) or at 42 months
²Change the engine oil.
²Replace the engine oil filter.
²Flush and replace the engine coolant if not done
at 36 months.
60,000 Miles (96 000 km) or at 48 months
²Change the engine oil.
²Replace the engine oil filter.
²Check the PCV valve and replace, if neces-
sary. Not required if previously changed.*
²Lubricate the front suspension lower ball joints.
²Replace the drive belts.
²Replace the engine air cleaner element (fil-
ter).
²Replace the ignition cables.
²Replace the spark plugs.
²Change the automatic transaxle fluid.
67,500 Miles (108 000 km) or at 54 months
²Change the engine oil.
²Replace the engine oil filter.
²Inspect the front brake pads and rear brake lin-
ings.
75,000 Miles (120 000 km) or at 60 months
²Change the engine oil.
²Replace the engine oil filter.
²Adjust the drive belt tension.
²Flush and replace engine coolant if has been
30,000 miles (48 000 km) or 24 months since last
change.
82,500 Miles (132 000 km) or at 66 months
²Change the engine oil.
²Replace the engine oil filter.
²Flush and replace engine coolant if it has been
30,000 miles (48 000 km) or 24 months since last
change.
90,000 Miles (144 000 km) or at 72 months
²Change the engine oil.
²Replace the engine oil filter.
²Check the PCV valve and replace, if neces-
sary. Not required if previously changed.*
²Lubricate the front suspension lower ball joints.
²Inspect the front brake pads and rear brake lin-
ings.
²Adjust the drive belt tension.
²Replace the engine air cleaner element (fil-
ter).
²Replace the spark plugs.
²Inspect the serpentine drive belt, replace if nec-
essary. This maintenance is not required if the belt
was previously replaced.
²Change the automatic transaxle fluid.
97,500 Miles (156 000 km) or at 78 months
²Change the engine oil.
²Replace the engine oil filter.
105,000 Miles (168 000 km) or at 84 months
²Change the engine oil.
²Replace the engine oil filter.
²Replace the engine timing belt.
²Adjust the drive belt tension.
*This maintenance is recommended by Daimler-
Chrysler Corporation to the owner but is not
required to maintain the emissions warranty.
NOTE: Inspection and service should also be per-
formed anytime a malfunction is observed or sus-
pected. Retain all receipts.
SCHEDULE ± B
3,000 Miles (5 000 km)
²Change the engine oil.
6,000 Miles (10 000 km)
²Change the engine oil.
²Replace the engine oil filter.
9,000 Miles (14 000 km)
²Change the engine oil.
²Inspect the front brake pads and rear brake lin-
ings.
0 - 4 LUBRICATION AND MAINTENANCEPL
SPECIFICATIONS (Continued)

12,000 Miles (19 000 km)
²Change the engine oil.
²Replace the engine oil filter.
15,000 Miles (24 000 km)
²Change the engine oil.
²Adjust the drive belt tension.
²Inspect theengine air cleaner element (fil-
ter).Replace as necessary.*
²Change the automatic transaxle fluid/filter and
adjust the bands.
18,000 Miles (29 000 km)
²Change the engine oil.
²Replace the engine oil filter.
²Inspect the front brake pads and rear brake lin-
ings.
21,000 Miles (34 000 km)
²Change the engine oil.
24,000 Miles (38 000 km)
²Change the engine oil.
²Replace the engine oil filter.
27,000 Miles (43 000 km)
²Change the engine oil.
²Inspect the front brake pads and rear brake lin-
ings.
30,000 Miles (48 000 km)
²Change the engine oil.
²Replace the engine oil filter.
²Inspect thePCV valveand replace as neces-
sary.*
²Lubricate the front suspension lower ball joints.
²Adjust the drive belt tension.
²Replace theengine air cleaner element (fil-
ter).
²Replace thespark plugs
²Change the automatic transaxle fluid/filter and
adjust bands.
33,000 Miles (53 000 km)
²Change the engine oil.
36,000 Miles (58 000 km)
²Change the engine oil.
²Replace the engine oil filter.
²Inspect the front brake pads and rear brake lin-
ings.
²Flush and replace the engine coolant.
39,000 Miles (62 000 km)
²Change the engine oil.
42,000 Miles (67 000 km)
²Change the engine oil.
²Replace the engine oil filter.
45,000 Miles (72 000 km)
²Change the engine oil.
²Inspect the front brake pads and rear brake lin-
ings.
²Inspect theengine air cleaner element (fil-
ter).Replace as necessary.*
²Adjust the drive belt tension.
²Change the automatic transaxle fluid/filter and
adjust bands.
48,000 Miles (77 000 km)
²Change the engine oil.
²Replace the engine oil filter.
51,000 Miles (82 000 km)
²Change the engine oil.
²Flush and replace the engine coolant.
54,000 Miles (86 000 km)
²Change the engine oil.
²Replace the engine oil filter.
²Inspect the front brake pads and rear brake lin-
ings.
57,000 Miles (91 000 km)
²Change the engine oil.
60,000 Miles (96 000 km)
²Change the engine oil.
²Replace the engine oil filter.
²Inspect thePCV valveand replace if neces-
sary.*
²Lubricate the front suspension lower ball joints.
²Replace the drive belts.
²Replace theengine air cleaner element (fil-
ter).
²Replace theignition cables
²Replace thespark plugs
²Check and replace, if necessary, theengine tim-
ing belton 3.0 liter engines.
²Change the automatic transaxle fluid/filter and
adjust bands.
63,000 Miles (101 000 km)
²Change the engine oil.
²Inspect the front brake pads and rear brake lin-
ings.
66,000 Miles (106 000 km)
²Change the engine oil.
²Replace the engine oil filter.
PLLUBRICATION AND MAINTENANCE 0 - 5
SPECIFICATIONS (Continued)

69,000 Miles (110 000 km)
²Change the engine oil.
72,000 Miles (115 000 km)
²Change the engine oil.
²Replace the engine oil filter.
²Inspect the front brake pads and rear brake lin-
ings.
75,000 Miles (120 000 km)
²Change the engine oil.
²Adjust the drive belt tension.
²Inspect theengine air cleaner element (fil-
ter)and replace as necessary.*
²Change the automatic transaxle fluid/filter and
adjust bands.
78,000 Miles (125 000 km)
²Change the engine oil.
²Replace the engine oil filter.
81,000 Miles (130 000 km)
²Change the engine oil.
²Flush and replace the engine coolant.
²Inspect the front brake pads and rear brake lin-
ings.
84,000 Miles (134 000 km)
²Change the engine oil.
²Replace the engine oil filter.
87,000 Miles (139 000 km)
²Change the engine oil.
90,000 Miles (144 000 km)
²Change the engine oil.
²Replace the engine oil filter.
²Inspect front brake pads and rear brake linings
²Check thePCV valveand replace if necessary.
Not required if previously changed.*
²Lubricate the front suspension lower ball joint.
²Replace theengine air cleaner element (fil-
ter).²Replace thespark plugs
²Change the automatic transaxle fluid/filter and
adjust the bands.
93,000 Miles (149 000 km)
²Change the engine oil.
96,000 Miles (154 000 km)
²Change the engine oil.
²Replace the engine oil filter.
99,000 Miles (158 000 km)
²Change the engine oil.
²Inspect the front brake pads and rear brake lin-
ings.
102,000 Miles (163 000 km)
²Change the engine oil.
²Replace the engine oil filter.
105,000 Miles (168 000 km)
²Replace theengine timing belt.
²Change the engine oil.
²Adjust the drive belt tension.
²Inspect theengine air cleaner element (fil-
ter)and replace as necessary.*
²Change the automatic transaxle fluid/filter and
adjust the bands.
²Flush and replace the engine coolant.
* This maintenance is recommended by Daimler-
Chrysler Corporation to the owner but is not
required to maintain the emissions warranty.
NOTE: Operating the vehicle more than 50% in
heavy traffic during hot weather, above 90É F (32É
C), using vehicle for police, taxi, limousine type
operation or trailer towing require the more fre-
quent transaxle service noted in Schedule ± B. Per-
form these services if vehicle usually operate under
these conditions.
Inspection and service should also be performed
anytime a malfunction is observed or suspected.
0 - 6 LUBRICATION AND MAINTENANCEPL
SPECIFICATIONS (Continued)

Loose cable connections will corrode, increase resis-
tance and permit water to enter the coil towers.
These conditions can cause ignition malfunction.
Plastic clips in various locations protect the cables
from damage. When the cables are replaced the clips
must be used to prevent damage to the cables, and
should be rotated about 30É below the horizontal.
ELECTRONIC IGNITION COILS
DESCRIPTION
The coil pack consists of 2 coils molded together.
The coil pack is mounted on the valve cover (Fig. 2).
OPERATION
WARNING: THE DIRECT IGNITION SYSTEM GEN-
ERATES APPROXIMATELY 40,000 VOLTS. PER-
SONAL INJURY COULD RESULT FROM CONTACT
WITH THIS SYSTEM.
High tension leads route to each cylinder from the
coil. The coil fires two spark plugs every power
stroke. One plug is the cylinder under compression,
the other cylinder fires on the exhaust stroke. Coil
number one fires cylinders 1 and 4. Coil number two
fires cylinders 2 and 3. The PCM determines which
of the coils to charge and fire at the correct time.
The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the energy in the coil
primary transfers to the secondary causing thespark. The PCM will de-energize the ASD relay if it
does not receive the crankshaft position sensor and
camshaft position sensor inputs. Refer to Auto Shut-
down (ASD) RelayÐPCM Output, in this section for
relay operation.
AUTOMATIC SHUTDOWN RELAY
DESCRIPTION
The ASD relay is located in the PDC (Fig. 3). The
inside top of the PDC cover has label showing relay
and fuse identification.
Fig. 1 Checking Spark Plug Electrode Gap
1 ± TAPER GAUGE
Fig. 2 Ignition Coil Pack
1 ± IGNITION COILS
2 ± SPARK PLUG CABLE
3 ± SPARK PLUG INSULATOR
Fig. 3 Power Distribution Center (PDC)
8D - 2 IGNITION SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

CAUTION: Do not drive cup plug into the casting
as restricted cooling can result and cause serious
engine problems.
INSTALLATION
Thoroughly clean all debris/rust from inside of cup
plug hole in cylinder block or head. Be sure to
remove old sealer. Lightly coat inside of cup plug hole
with MopartStud and Bearing Mount Adhesive.
Make certain the new plug is cleaned of all oil or
grease. Using a proper driver, drive plug into hole so
that the sharp edge of the plug is at least 0.5 mm
(0.020 inch.) inside the lead in chamfer (Fig. 3).
It is not necessary to wait for curing of the sealant.
The cooling system can be refilled and the vehicle
placed in service immediately.
ENGINE PERFORMANCE
If a loss of performance is noticed, timing belt or
chain may have skipped one or two teeth. Camshaft
and crankshaft timing should be checked. Refer to
Group 9, Engine Timing belt or chain installation.
It is important that the vehicle is operating to it's
optimum performance level to maintain fuel economy
and lowest vehicle emissions. If vehicle is not operat-ing to these standards, refer to Engine Diagnosis in
this section. The following procedures can assist in
achieving the proper engine diagnosis.
(1) Test cranking amperage draw. Refer to Group
8B, Starting.
(2) Check intake manifold for vacuum leaks.
(3) Perform cylinder compression pressure test.
Refer to Engine Diagnosis in this section.
(4) Clean or replace spark plugs as necessary and
adjust gap as specified in Group 8D, Ignition System.
Tighten to specifications.
(5) Test resistance of spark plug cables. Refer to
Group 8D, Ignition System.
(6) Test ignition coils primary and secondary resis-
tance. Replace parts as necessary. Refer to Group 8D,
Ignition System.
(7) Check fuel pump pressure at idle and different
RPM ranges. Refer to Group 14, Fuel System for
specifications.
(8) The air filter elements should be replaced as
specified in Group 0, Lubrication and Maintenance.
(9) Inspect crankcase ventilation system. Refer to
Group 25, Emission Control Systems.
(10) Road test vehicle as a final test.HONING CYLINDER BORES
(1) Used carefully, the cylinder bore resizing hone,
recommended tool C-823 or equivalent, equipped
with 220 grit stones, is the best tool for this honing
procedure. In addition to deglazing, it will reduce
taper and out-of-round as well as removing light
scuffing, scoring or scratches. Usually a few strokes
Fig. 2 Access Plug
1 ± CRANKSHAFT BOLT ACCESS PLUG
2 ± RIGHT MOUNT BOLT ACCESS PLUG
3 ± FASCIA
4 ± SPLASH SHIELD
Fig. 3 Core Hole Plug Removal
1 ± CYLINDER BLOCK
2 ± REMOVE PLUG WITH PLIERS
3 ± STRIKE HERE WITH HAMMER
4 ± DRIFT PUNCH
5 ± CUP PLUG
PLENGINE 9 - 3
GENERAL INFORMATION (Continued)

²When checking #2 main bearing shim #1 & #3
main bearing.
²When checking #3 main bearing shim #2 & #4
main bearing.
²When checking #4 main bearing shim #3 main
bearing.
NOTE: REMOVE ALL SHIMS BEFORE REASSEM-
BLING ENGINE
ALTERNATIVE METHOD
The weight of the crankshaft can be supported by a
jack under the counterweight adjacent to the bearing
being checked.
PLASTIGAGE PROCEDURE
(1) Remove oil film from surface to be checked.
Plastigage is soluble in oil.
(2) Place a piece of Plastigage across the entire
width of the bearing shell in the cap approximately
6.35 mm (1/4 in.) off center and away from the oil
holes (Fig. 5). (In addition, suspected areas can be
checked by placing the Plastigage in the suspected
area). Torque the bearing cap bolts of the bearing
being checked to the proper specifications.
(3) Remove the bearing cap and compare the width
of the flattened Plastigage (Fig. 6) with the metric
scale provided on the package. Locate the band clos-
est to the same width. This band shows the amount
of clearance in thousandths of a millimeter. Differ-
ences in readings between the ends indicate the
amount of taper present. Record all readings taken.
Refer to Engine Specifications.Plastigage gener-
ally is accompanied by two scales. One scale is
in inches, the other is a metric scale.
NOTE: Plastigage is available in a variety of clear-
ance ranges. Use the most appropriate range for
the specifications you are checking.
CONNECTING ROD BEARING CLEARANCE
Engine connecting rod bearing clearances can be
determined by use of Plastigage or equivalent. Thefollowing is the recommended procedure for the use
of Plastigage:
(1) Rotate the crankshaft until the connecting rod
to be checked is at the bottom of its stroke.
(2) Remove oil film from surface to be checked.
Plastigage is soluble in oil.
(3) Place a piece of Plastigage across the entire
width of the bearing shell in the bearing cap approx-
imately 6.35 mm (1/4 in.) off center and away from
the oil hole (Fig. 5). In addition, suspect areas can be
checked by placing plastigage in that area.
(4) Assemble the rod cap with Plastigage in place.
Tighten the rod cap to the specified torque.Do not
rotate the crankshaft while assembling the cap
or the Plastigage may be smeared, giving inac-
curate results.
(5) Remove the bearing cap and compare the width
of the flattened Plastigage (Fig. 6) with the scale pro-
vided on the package. Locate the band closest to the
same width. This band indicates the amount of oil
clearance. Differences in readings between the ends
indicate the amount of taper present. Record all
readings taken. Refer to Engine Specifications.Plas-
tigage generally is accompanied by two scales.
One scale is in inches, the other is a metric
scale. If the bearing clearance exceeds wear
limit specification, replace the bearing.
REPAIR OF DAMAGED OR WORN THREADS
Damaged or worn threads (including aluminum
head spark plug threads) can be repaired. Essen-
tially, this repair consists of drilling out worn or
damaged threads, tapping the hole with a special
Heli-Coil Tap, (or equivalent) and installing an insert
into the tapped hole. This brings the hole back to its
original thread size.
CAUTION: Be sure that the tapped holes maintain
the original centerline.
Heli-Coil tools and inserts are readily available
from automotive parts jobbers.
HYDROSTATIC LOCKED ENGINE
When an engine is suspected to be hydrostatically
locked, regardless of what caused the problem, the
following steps should be used.
CAUTION: DO NOT use starter motor to rotate the
engine, severe damage may occur.
(1) Inspect air cleaner, induction system and
intake manifold to insure system is dry and clear of
foreign material.
(2) Remove negative battery cable.
(3) Place a shop towel around the spark plugs
when removing them from the engine. This will catch
Fig. 6 Clearance Measurement
PLENGINE 9 - 5
GENERAL INFORMATION (Continued)

should not be disassembled to determine the
cause of low compression unless some malfunc-
tion is present.
(11) Clean or replace spark plugs as necessary and
adjust gap as specified in Group 8, Electrical.
Tighten to specifications.
(12) Test resistance of spark plug cables. Refer to
Group 8, Electrical Ignition System Secondary Cir-
cuit Inspection.
(13) Test coil output voltage, primary and second-
ary resistance. Replace parts as necessary. Refer to
Group 8, Electrical Ignition System.
(14) Check fuel pump pressure at idle and differ-
ent RPM ranges. Refer to Group 14, Fuel System for
Specifications.
(15) The air filter elements should be replaced as
specified in Group 0, Lubrication and Maintenance.
(16) Inspect crankcase ventilation system as out
lined in Group 0, Lubrication and Maintenance. For
emission controls see Group 25, Emission Controls
for service procedures.
(17) Inspect and adjust accessory belt drives refer-
ring to Group 7, Cooling System, Accessory Drive
Belts for proper adjustments.
(18) Road test vehicle as a final test.
CYLINDER COMBUSTION PRESSURE LEAKAGE
TEST
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
²Exhaust and intake valve leaks (improper seat-
ing).
²Leaks between adjacent cylinders or into water
jacket.
²Any causes for combustion/compression pressure
loss.
WARNING: DO NOT REMOVE THE RADIATOR CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE
BECAUSE SERIOUS BURNS FROM COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the radiator cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn the engine
OFF.
Clean spark plug recesses with compressed air.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
Calibrate the tester according to the manufactur-
er's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1,379kPa (200 psi) maximum, with 552 kPa (80 psi) rec-
ommended.
Perform the test procedures on each cylinder
according to the tester manufacturer's instructions.
While testing, listen for pressurized air escaping
through the throttle body, tailpipe and oil filler cap
opening. Check for bubbles in the radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage per cylinder.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder.
LASH ADJUSTER (TAPPET) NOISE DIAGNOSIS
A tappet-like noise may be produced from several
items. Check the following items.
(1) Engine oil level too high or too low. This may
cause aerated oil to enter the adjusters and cause
them to be spongy.
(2) Insufficient running time after rebuilding cylin-
der head. Low speed running up to 1 hour may be
required.
(3) During this time, turn engine off and let set for
a few minutes before restarting. Repeat this several
times after engine has reached normal operating
temperature.
(4) Low oil pressure.
(5) The oil restrictor pressed into the vertical oil
passage to the cylinder head is plugged with debris.
(6) Air ingested into oil due to broken or cracked
oil pump pick up.
(7) Worn valve guides.
(8) Rocker arm ears contacting valve spring
retainer.
(9) Rocker arm loose, adjuster stuck or at maxi-
mum extension and still leaves lash in the system.
(10) Faulty lash adjuster.
a. Check lash adjusters for sponginess while
installed in cylinder head. Depress part of rocker
arm over adjuster. Normal adjusters should feel very
firm. Spongy adjusters can be bottomed out easily.
b. Remove suspected rocker arms (sohc) or lash
adjuster (dohc) and replace.
ENGINE OIL LEAK INSPECTION
Begin with a thorough visual inspection of the
engine, particularly at the area of the suspected leak.
If an oil leak source is not readily identifiable, the
following steps should be followed:
(1) Do not clean or degrease the engine at this
time because some solvents may cause rubber to
swell, temporarily stopping the leak.
(2) Add an oil soluble dye (use as recommended by
manufacturer). Start the engine and let idle for
approximately 15 minutes. Check the oil dipstick to
PLENGINE 9 - 9
DIAGNOSIS AND TESTING (Continued)

ENGINE DIAGNOSISÐPERFORMANCE
CONDITION POSSIBLE CAUSE CORRECTION
ENGINE WILL NOT START 1. Weak battery. 1. Test battery. Charge or replace
as necessary. Refer to Group 8A,
Battery.
2. Corroded or loose battery
connections.2. Clean and tighten battery
connections. Apply a coat of light
mineral grease to terminals.
3. Faulty starter. 3. Test starting system. Refer to
Group 8B, Starting.
4. Faulty coil(s) or control unit. 4. Test and replace as needed.
Refer to Group 8D, Ignition System.
5. Incorrect spark plug gap. 5. Set gap. Refer to Group 8D,
Ignition System.
6. Contamination in fuel system. 6. Clean system and replace fuel
filter.
7. Faulty fuel pump. 7. Test fuel pump and replace as
needed. Refer to Group 14, Fuel
System.
8. Incorrect engine timing. 8. Check for a skipped timing
belt/chain.
ENGINE STALLS OR IDLES
ROUGH1. Idle speed too low. 1. Test minimum air flow. Refer to
Group 14, Fuel System.
2. Incorrect fuel mixture. 2. Refer to Group 14, Fuel System.
3. Intake manifold leakage. 3. Inspect intake manifold, manifold
gasket, and vacuum hoses.
4. Faulty coil(s). 4. Test and replace as necessary.
Refer to Group 8D, Ignition System.
ENGINE LOSS OF POWER 1. Dirty or incorrectly gapped plugs. 1. Clean plugs and set gap. Refer to
Group 8D, Ignition System.
2. Contamination in fuel system. 2. Clean system and replace fuel
filter.
3. Faulty fuel pump. 3. Test and replace as necessary.
Refer to Group 14, Fuel System.
4. Incorrect valve timing. 4. Correct valve timing.
5. Leaking cylinder head gasket. 5. Replace cylinder head gasket.
6. Low compression. 6. Test compression of each
cylinder.
7. Burned, warped, or pitted valves. 7. Replace valves.
8. Plugged or restricted exhaust
system.8. Install new parts, as necessary.
9. Faulty coil(s). 9. Test and replace as necessary.
Refer to Group 8D, Ignition System.
PLENGINE 9 - 11
DIAGNOSIS AND TESTING (Continued)

CONDITION POSSIBLE CAUSE CORRECTION
ENGINE MISSES ON
ACCELERATION1. Dirty or incorrectly gapped spark
plugs.1. Clean spark plugs and set gap.
Refer to Group 8D, Ignition System.
2. Contamination in Fuel System. 2. Clean fuel system and replace
fuel filter.
3. Burned, warped, or pitted valves. 3. Replace valves.
4. Faulty coil(s). 4. Test and replace as necessary.
Refer to Group 8D, Ignition System.
ENGINE MISSES AT HIGH SPEED 1. Dirty or incorrect spark plug gap. 1. Clean spark plugs and set gap.
Refer to Group 8D, Ignition System.
2. Faulty coil(s). 2. Test and replace as necessary.
Refer to Group 8D, Ignition System.
3. Dirty fuel injector(s). Test and replace as necessary.
Refer to Group 14, Fuel System.
4. Contamination in fuel system. 4. Clean system and replace fuel
filter.
ENGINE DIAGNOSISÐMECHANICAL
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. Low oil pressure. 3. Check and correct engine oil
level.
4. Dirt in tappets/lash adjusters. 4. Replace rocker arm/hydraulic
lash adjuster assembly.
5. Worn rocker arms. 5. Inspect oil supply to rocker arms.
6. Worn tappets/lash adjusters. 6. Install new rocker arm/hydraulic
lash adjuster assembly.
7. Worn valve guides. 7. Ream guides and install new
valves with oversize stems.
8. Excessive runout of valve seats
on valve faces.8. Grind valve seats and valves.
9. Missing adjuster pivot. 9. Replace rocker arm/hydraulic
lash adjuster assembly.
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. Excessive bearing clearance. 4. Measure bearings for correct
clearance. Repair as necessary.
5. Connecting rod journal
out-of-round.5. Replace crankshaft or grind
surface.
6. Misaligned connecting rods. 6. Replace bent connecting rods.
9 - 12 ENGINEPL
DIAGNOSIS AND TESTING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
OIL CONSUMPTION OR SPARK
PLUGS FOULED1. PCV system malfunction. 1. Check system and repair as
necessary. Refer to Group 25,
Emission Control Systems.
2. Worn, scuffed or broken rings. 2. Hone cylinder bores. Install new
rings.
3. Carbon in oil ring slots. 3. Install new rings.
4. Rings fitted too tightly in grooves. 4. Remove rings and check
grooves. If groove is not proper
width, replace piston.
5. Worn valve guide(s). 5. Ream guide(s) and replace
valve(s) with oversize valve(s) and
seal(s).
6. Valve stem seal(s) worn or
damaged.6. Replace seal(s).
9 - 14 ENGINEPL
DIAGNOSIS AND TESTING (Continued)