Dodge Durango (HB). Manual — part 1081
CONDITION
POSSIBLE CAUSE
CORRECTION
ENGINE LOSS OF POWER
1. Dirty or incorrectly gapped spark
plugs.
1. Replace spark plugs.
2. Dirt or water in fuel system.
2. Clean system and replace fuel
filter.
3. Blown cylinder head gasket.
3. Replace cylinder head gasket.
4. Low compression.
4. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
5. Burned, warped or pitted valves.
5. Replace as necessary.
6. Plugged or restricted exhaust
system.
6. Inspect and replace as
necessary.
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - MECHANICAL
CONDITION
POSSIBLE CAUSES
CORRECTIONS
NOISY VALVES
1. High or low oil level in
crankcase.
1. (Refer to LUBRICATION &
MAINTENANCE -
SPECIFICATIONS)
2. Thin or diluted oil.
2. Change oil and filter.
3. Low oil pressure.
3. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
4. Dirt in lash adjusters.
4. Replace as necessary.
5. Worn rocker arms.
5. Replace as necessary.
6. Worn lash adjusters
6. Replace as necessary.
7. Worn valve guides.
7. (Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES
& SEATS - STANDARD
PROCEDURE)
8. Excessive runout of valve seats
on valve faces.
8. (Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES
& SEATS - STANDARD
PROCEDURE)
CONNECTING ROD NOISE
1. Insufficient oil supply.
1. (Refer to LUBRICATION &
MAINTENANCE -
SPECIFICATIONS)
2. Low oil pressure.
2. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
3. Thin or diluted oil.
3. Change oil and filter.
4. Excessive bearing clearance.
4. Replace as necessary.
5. Connecting rod journal
out-of-round.
5. Service or replace crankshaft.
6. Misaligned connecting rods.
6. Replace bent connecting rods.
HB
ENGINE - 5.7L SERVICE INFORMATION
9 - 1323
CONDITION
POSSIBLE CAUSES
CORRECTIONS
MAIN BEARING NOISE
1. Insufficient oil supply.
1. (Refer to LUBRICATION &
MAINTENANCE -
SPECIFICATIONS)
2. Low oil pressure.
2. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
3. Thin or diluted oil.
3. Change oil and filter.
4. Excessive bearing clearance.
4. Replace as necessary.
5. Excessive end play.
5. Check thrust washers for wear.
6. Crankshaft journal out-of round.
6. Service or replace crankshaft.
7. Loose flywheel or torque
converter.
7. Tighten to correct torque
DIAGNOSIS AND TESTING - CYLINDER COMPRESSION PRESSURE
The results of a cylinder compression pressure test can be utilized to diagnose several engine malfunctions.
Ensure the battery is completely charged and the engine starter motor is in good operating condition. Otherwise the
indicated compression pressures may not be valid for diagnosis purposes.
1. Clean the spark plug recesses with compressed air.
2. Remove the spark plugs.
3. Disable the fuel system (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY - DESCRIPTION).
4. Remove the ASD relay (Refer to 8 - ELECTRICAL/IGNITION CONTROL/AUTO SHUT DOWN RELAY -
REMOVAL).
5. Insert a compression pressure gauge and rotate the engine with the engine starter motor for three revolutions.
6. Record the compression pressure on the 3rd revolution. Continue the test for the remaining cylinders.
7.
(Refer to 9 - ENGINE - SPECIFICATIONS) for the correct engine compression pressures.
DIAGNOSIS AND TESTING - CYLINDER COMBUSTION PRESSURE LEAKAGE
The combustion pressure leakage test provides an accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
•
Exhaust and intake valve leaks (improper seating).
•
Leaks between adjacent cylinders or into water jacket.
•
Any causes for combustion/compression pressure loss.
1. Check the coolant level and fill as required. DO NOT install the radiator cap.
2. Start and operate the engine until it attains normal operating temperature, then turn the engine OFF.
3. Remove the spark plugs.
4. Remove the oil filler cap.
5. Remove the air cleaner hose.
6. Calibrate the tester according to the manufacturer’s instructions. The shop air source for testing should maintain
483 kPa (70 psi) minimum, 1,379 kPa (200 psi) maximum and 552 kPa (80 psi) recommended.
7. Perform the test procedures on each cylinder according to the tester manufacturer’s instructions. Set piston of
cylinder to be tested at TDC compression,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.
FOR EXAMPLE: At 552 kPa (80 psi) input pressure, a minimum of 414 kPa (60 psi) should be maintained in the
cylinder.
Refer to CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART .
9 - 1324
ENGINE - 5.7L SERVICE INFORMATION
HB
CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART
CONDITION
POSSIBLE CAUSE
CORRECTION
AIR ESCAPES THROUGH
THROTTLE BODY
Intake valve bent, burnt, or not
seated properly
Inspect valve and valve seat.
Reface or replace, as necessary.
Inspect valve springs. Replace as
necessary.
AIR ESCAPES THROUGH
TAILPIPE
Exhaust valve bent, burnt, or not
seated properly
Inspect valve and valve seat.
Reface or replace, as necessary.
Inspect valve springs. Replace as
necessary.
AIR ESCAPES THROUGH
RADIATOR
Head gasket leaking or cracked
cylinder head or block
Remove cylinder head and inspect.
Replace defective part
MORE THAN 50% LEAKAGE
FROM ADJACENT CYLINDERS
Head gasket leaking or crack in
cylinder head or block between
adjacent cylinders
Remove cylinder head and inspect.
Replace gasket, head, or block as
necessary
MORE THAN 25% LEAKAGE AND
AIR ESCAPES THROUGH OIL
FILLER CAP OPENING ONLY
Stuck or broken piston rings;
cracked piston; worn rings and/or
cylinder wall
Inspect for broken rings or piston.
Measure ring gap and cylinder
diameter, taper and out-of-round.
Replace defective part as necessary
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - LUBRICATION
CONDITION
POSSIBLE CAUSES
CORRECTION
OIL LEAKS
1. Gaskets and O-Rings.
1.
(a) Misaligned or damaged.
(a) Replace as necessary.
(b) Loose fasteners, broken or
porous metal parts.
(b) Tighten fasteners, Repair or
replace metal parts.
2. Crankshaft rear seal
2. Replace as necessary.
3. Crankshaft seal flange.
Scratched, nicked or grooved.
3. Polish or replace crankshaft.
4. Oil pan flange cracked.
4. Replace oil pan.
5.Front cover seal, damaged or
misaligned.
5. Replace seal.
6. Scratched or damaged vibration
damper hub.
6. Polish or replace damper.
7. Crankshaft Rear Flange
Microporosity
7. Replace Crankshaft
OIL PRESSURE DROP
1. Low oil level.
1. Check and correct oil level.
2. Faulty oil pressure sending unit.
2. Replace sending unit.
3. Low oil pressure.
3. Check pump and bearing
clearance.
4. Clogged oil filter.
4. Replace oil filter.
5. Worn oil pump.
5. Replace as necessary.
6. Thin or diluted oil.
6. Change oil and filter.
7. Excessive bearing clearance.
7. Replace as necessary.
8. Oil pump relief valve stuck.
8. Replace oil pump.
9. Oil pickup tube loose or
damaged.
9. Replace as necessary.
HB
ENGINE - 5.7L SERVICE INFORMATION
9 - 1325
CONDITION
POSSIBLE CAUSES
CORRECTION
OIL PUMPING AT RINGS; SPARK
PLUGS FOULING
1. Worn or damaged rings.
1. Hone cylinder bores and replace
rings.
2. Carbon in oil ring slots.
2. Replace rings.
3. Incorrect ring size installed.
3. Replace rings.
4. Worn valve guides.
4. Ream guides and replace valves.
5. Leaking intake gasket.
5. Replace intake gaskets.
6. Leaking valve guide seals.
6. Replace valve guide seals.
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - MECHANICAL
ENGINE MECHANICAL DIAGNOSIS CHART
CONDITION
POSSIBLE CAUSES
CORRECTION
NOISY VALVES/LIFTERS
1. High or low oil level in crankcase
1. Check for correct oil level. Adjust
oil level by draining or adding as
needed
2. Thin or diluted oil
2. Change oil. (Refer to 9 -
ENGINE/LUBRICATION/OIL -
STANDARD PROCEDURE)
3. Low oil pressure
3. Check engine oil level. If ok,
Perform oil pressure test. (Refer to
9 - ENGINE/LUBRICATION -
DIAGNOSIS AND TESTING) for
engine oil pressure test/
specifications
4. Dirt in tappets/lash adjusters
4. Clean/replace hydraulic
tappets/lash adjusters
5. Bent push rod(s)
5. Install new push rods
6. Worn rocker arms
6. Inspect oil supply to rocker arms
and replace worn arms as needed
7. Worn tappets/lash adjusters
7. Install new hydraulic tappets/lash
adjusters
8. Worn valve guides
8. Inspect all valve guides and
replace as necessary
9. Excessive runout of valve seats
or valve faces
9. Grind valves and seats
9 - 1326
ENGINE - 5.7L SERVICE INFORMATION
HB
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