Dodge Durango (DN). Manual — part 453

SERVICE DIAGNOSIS—GASOLINE ENGINES

PERFORMANCE DIAGNOSIS CHART—GASOLINE ENGINES

CONDITION

POSSIBLE CAUSES

CORRECTION

ENGINE WILL
NOT CRANK

1. Weak or dead battery

1. Charge/Replace Battery. Refer to Group 8A,
Battery, for correct procedures. Check charging
system. Refer to Group 8C, Charging Systems, for
correct procedures.

2. Corroded or loose battery
connections

2. Clean/tighten suspect battery/starter connections

3. Faulty starter or related circuit(s)

3. Check starting system. Refer to Group 8B,
Starting Systems, for correct diagnostics/procedures

4. Seized accessory drive
component

4. Remove accessory drive belt and attempt to start
engine. If engine starts, repair/replace seized
component.

5. Engine internal mechanical
failure or hydro-static lock

5. Refer to Group 9, Engine, for correct diagnostics/
procedures

ENGINE CRANKS
BUT WILL NOT
START

1. No spark

1. Check for spark. Refer to Group 8D, Ignition
System, for correct procedures.

2. No fuel

2. Perform fuel pressure test, and if necessary,
inspect fuel injector(s) and driver circuits. Refer to
Group 14, Fuel System, for correct procedures.

3. Low or no engine compression

3. Perform cylinder compression pressure test. Refer
to Group 9, Engine, for correct procedures.

ENGINE LOSS OF
POWER

1. Worn or burned distributor rotor

1. Install new distributor rotor

2. Worn distributor shaft

2. Remove and repair distributor (Refer to Group 8D,
Ignition System

3. Worn or incorrect gapped spark
plugs

3. Clean plugs and set gap. (Refer to Group 8D,
Ignition System)

4. Dirt or water in fuel system

4. Clean system and replace fuel filter

5. Faulty fuel pump

5. Install new fuel pump

6. Incorrect valve timing

6. Correct valve timing

7. Blown cylinder head gasket

7. Install new cylinder head gasket

8. Low compression

8. Test cylinder compression

9. Burned, warped, or pitted valves

9. Install/Reface valves as necessary

10. Plugged or restricted exhaust
system

10. Install new parts as necessary

11. Faulty ignition cables

11. Replace any cracked or shorted cables

12. Faulty ignition coil

12. Test and replace, as necessary (Refer to Group
8D, Ignition System)

ENGINE STALLS
OR ROUGH IDLE

1. Carbon build-up on throttle plate

1. Remove throttle body and de-carbon. (Refer to
Group 14 for correct procedures)

2. Engine idle speed too low

2. Check Idle Air Control circuit. (Refer to Group 14,
Fuel System)

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5.9L ENGINE

DN

DIAGNOSIS AND TESTING (Continued)

CONDITION

POSSIBLE CAUSES

CORRECTION

3. Worn or incorrectly gapped spark
plugs

3. Replace or clean and re-gap spark plugs (Refer to
group 8D, Ignition System)

4. Worn or burned distributor rotor

4. Install new distributor rotor

5. Spark plug cables defective or
crossed

5. Check for correct firing order or replace spark plug
cables. (Refer to Group 8D, Ignition System for
correct procedures.)

6. Faulty coil

6. Test and replace, if necessary (Refer to group 8D,
Ignition System)

7. Intake manifold vacuum leak

7. Inspect intake manifold gasket and vacuum hoses.
Replace if necessary

8. EGR valve leaking or stuck open

8. Test and replace, if necessary (Refer to group 25,
Emission Control Systems)

ENGINE MISSES
ON
ACCELERATION

1. Worn or incorrectly gapped spark
plugs

1. Replace spark plugs or clean and set gap. (Refer
to group 8D, Ignition System)

2. Spark plug cables defective or
crossed

2. Replace or rewire secondary ignition cables. Refer
to Group 8D, Ignition System

3. Dirt in fuel system

3. Clean fuel system

4. Burned, warped or pitted valves

4. Install new valves

5. Faulty coil

5. Test and replace as necessary (refer to group 8D,
Ignition System)

MECHANICAL DIAGNOSIS CHART—GASOLINE ENGINES

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 Engine Oil Service in this group)

3. Low oil pressure

3. Check engine oil level. If ok, Perform oil pressure test. Refer to
this group 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

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5.9L ENGINE

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DIAGNOSIS AND TESTING (Continued)

CONDITION

POSSIBLE CAUSES

CORRECTION

CONNECTING
ROD NOISE

1. Insufficient oil supply

1. Check engine oil level. (Refer to group 0, Lubrication and
Maintenance)

2. Low oil pressure

2. Check engine oil level. If ok, Perform oil pressure test. Refer to
this group for engine oil pressure test/specifications

3. Thin or diluted oil

3. Change oil to correct viscosity. Refer to this group for correct
procedure/engine oil specifications

4. Excessive connecting
rod bearing clearance

Measure bearings for correct clearance with plasti-gage. Repair
as necessary

5. Connecting rod
journal out of round

5. Replace crankshaft or grind journals

6. Misaligned
connecting rods

6. Replace bent connecting rods

MAIN BEARING
NOISE

1. Insufficient oil supply

1. Check engine oil level. (Refer to group 0, Lubrication and
Maintenance)

2. Low oil pressure

2. Check engine oil level. If ok, Perform oil pressure test. Refer to
this group for engine oil pressure test/specifications

3. Thin or diluted oil

3. Change oil to correct viscosity. Refer to this group for correct
procedure/engine oil specifications

4. Excessive main
bearing clearance

4. Measure bearings for correct clearance. Repair as necessary

5. Excessive end play

5. Check crankshaft thrust bearing for excessive wear on flanges

6. Crankshaft main
journal out of round or
worn

6. Grind journals or replace crankshaft

7. Loose flywheel or
torque converter

7. Inspect crankshaft, flexplate/flywheel and bolts for damage.
Tighten to correct torque

LOW OIL
PRESSURE

1. Low oil level

1. Check oil level and fill if necessary

2. Faulty oil pressure
sending unit

2. Install new sending unit

3. Clogged oil filter

3. Install new oil filter

4. Worn oil pump

4. Replace worn gears or oil pump assy

5. Thin or diluted oil

5. Change oil to correct viscosity. Refer to this group for correct
procedure/engine oil specifications

6. Excessive bearing
clearance

6. Measure bearings for correct clearance

7. Oil pump relief valve
stuck

7. Remove valve to inspect, clean and reinstall

8. Oil pump suction
tube loose, broken, bent
or clogged

8. Inspect suction tube and clean or replace if necessary

9. Oil pump cover
warped or cracked

9. Install new oil pump

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5.9L ENGINE

DN

DIAGNOSIS AND TESTING (Continued)

CONDITION

POSSIBLE CAUSES

CORRECTION

OIL LEAKS

1. Misaligned or
deteriorated gaskets

1. Replace gasket

2. Loose fastener,
broken or porous metal
part

2. Tighten, repair or replace the part

3. Front or rear
crankshaft oil seal
leaking

3. Replace seal

4. Leaking oil gallery
plug or cup plug

4. Remove and reseal threaded plug. Replace cup style plug

5. Leaking intake

5. Replace gaskets

manifold cross-over

gaskets

EXCESSIVE OIL
CONSUMPTION
OR SPARK
PLUGS OIL
FOULED

1. PCV System
malfunction

1. Refer to group 25, Emission Control System for correct
operation

2. Intake manifold

2. Replace plenum

plenum pan gasket

pan gasket

failure

3. Defective valve

3. Replace seals

stem seal(s)

4. Worn or broken
piston rings

4. Hone cylinder bores. Install new rings

5. Scuffed pistons/
cylinder walls

5. Hone cylinder bores and replace pistons as required

6. Carbon in oil control
ring groove

6. Remove rings and de-carbon piston

7. Worn valve guides

6. Repair as

necessary

8. Piston rings fitted

8. Remove rings and

too tightly in grooves

check ring end gap

and side clearance.

Replace if necessary

INTAKE MANIFOLD LEAKAGE DIAGNOSIS

An intake manifold air leak is characterized by

lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.

WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS, OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.

(1) Start the engine.
(2) Spray a small stream of water at the suspected

leak area.

(3) If a change in RPMs, the area of the suspected

leak has been found.

(4) Repair as required.

CYLINDER COMPRESSION PRESSURE TEST

The results of a cylinder compression pressure test

can be utilized to diagnose several engine malfunc-
tions.

DN

5.9L ENGINE

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DIAGNOSIS AND TESTING (Continued)