Service Diagnosis—Lubrication - Dodge 2000 DURANGO Service Manual

DN
DIAGNOSIS AND TESTING (Continued)
SERVICE DIAGNOSIS—LUBRICATION
CONDITION
OIL LEAKS
OIL PRESSURE DROP
OIL PUMPING AT RINGS; SPARK
PLUGS FOULING
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.
POSSIBLE CAUSES
1. Gaskets and O-Rings.
(a) Misaligned or damaged.
(b) Loose fasteners, broken or
porous metal parts.
2. Crankshaft rear seal
3. Crankshaft seal flange.
Scratched, nicked or grooved.
4. Oil pan flange cracked.
5. Timing chain cover seal,
damaged or misaligned.
6. Scratched or damaged vibration
damper hub.
1. Low oil level.
2. Faulty oil pressure sending unit.
3. Low oil pressure.
4. Clogged oil filter.
5. Worn oil pump.
6. Thin or diluted oil.
7. Excessive bearing clearance.
8. Oil pump relief valve stuck.
9. Oil pump suction tube loose or
damaged.
1. Worn or damaged rings.
2. Carbon in oil ring slots.
3. Incorrect ring size installed.
4. Worn valve guides.
5. Leaking intake gasket.
6. Leaking valve guide seals.
(2) Spray a small stream of water at the suspected
leak area.
(3) If a change in RPM is observed 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.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
4.7L ENGINE
CORRECTION
1.
(a) Replace as necessary.
(b) Tighten fasteners, Repair or
replace metal parts.
2. Replace as necessary.
3. Polish or replace crankshaft.
4. Replace oil pan.
5. Replace seal.
6. Polish or replace damper.
1. Check and correct oil level.
2. Replace sending unit.
3. Check pump and bearing
clearance.
4. Replace oil filter.
5. Replace as necessary.
6. Change oil and filter.
7. Replace as necessary.
8. Clean or replace relief valve.
9. Replace as necessary.
1. Hone cylinder bores and replace
rings.
2. Replace rings.
3. Replace rings.
4. Ream guides and replace valves.
5. Replace intake gaskets.
6. Replace valve guide seals.
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