Dodge Nitro. Manual — part 2

ENGINE PERFORMANCE DIAGNOSTIC TABLE

CONDITION

POSSIBLE CAUSES

CORRECTION

OIL LEAKS

1. Gaskets and O-Rings.

-

(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. See
REMOVAL.

3. Crankshaft seal flange.
Scratched, nicked or grooved.

3. Polish or replace crankshaft.

4. Oil pan flange cracked.

4. Replace oil pan. See
REMOVAL.

5. Timing chain cover seal
damaged.

5. Re-seal timing cover.

6. Scratched or damaged vibration
damper hub.

6. Polish or replace damper.

OIL PRESSURE DROP

1. Low oil level.

1. Check and correct oil level.

2. Faulty oil pressure sending unit. 2. Replace sending unit. See

REMOVAL.

3. Low oil pressure.

3. Check oil pump and bearing
clearance.

4. Clogged oil filter.

4. Replace oil filter. See
REMOVAL.

5. Worn oil pump.

5. Replace oil pump. See
REMOVAL.

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. See
REMOVAL.

9. Oil pick up tube loose, damaged
or clogged.

9. Replace as necessary.

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. See
STANDARD PROCEDURE.

3. Incorrect ring size installed.

3. Replace rings. See
STANDARD PROCEDURE.

4. Worn valve guides.

4. Ream guides and replace
valves. See STANDARD
PROCEDURE.

5. Leaking valve guide seals.

5. Replace valve guide seals.

CONDITION

POSSIBLE

CORRECTION

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

CAUSE

ENGINE WILL

NOT START

1. Weak battery

1. Charge or replace
as necessary.

2. Corroded or loose
battery connections.

2. Clean and tighten
battery connections.
Apply a coat of
light mineral grease
to the terminals.

3. Faulty starter.

3. Refer to
DIAGNOSIS AND
TESTING .

4. Faulty coil or
control unit.

4. Refer to
REMOVAL .

5. Incorrect spark
plug gap.

5.

6. Incorrect right
bank cam timing.

6. Refer to engine
timing in this
article.

7. Dirt or water in
fuel system.

7. Clean system and
replace fuel filter.

8. Faulty fuel pump,
relay or wiring.

8. Repair or replace
as necessary.

9. Faulty cam or
crank sensor

9. Refer to Ignition
system.

ENGINE STALLS
OR ROUGH IDLE

1. Vacuum leak.

1. Inspect intake
manifold and
vacuum hoses,
repair or replace as
necessary.

-

2. Faulty crank
position sensor

2. Replace crank
position sensor.

3. Faulty coil.

3. Refer to
REMOVAL .

4. Incorrect cam
timing.

4. See STANDARD
PROCEDURE.

ENGINE LOSS OF
POWER

1. Dirty or
incorrectly gapped
spark plugs.

1. Refer to SPARK
PLUG

2. Dirt or water in
fuel system.

2. Clean system and
replace fuel filter.

3. Faulty fuel pump. 3. (Refer to PUMP-

FUEL ).

4. Blown cylinder
head gasket.

4. Replace cylinder
head gasket.

5. Low

5. See

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

STANDARD PROCEDURE

ENGINE GASKET SURFACE PREPARATION

compression.

DIAGNOSIS AND
TESTING, repair
as necessary.

6. Burned, warped
or pitted valves.

6. Replace as
necessary.

7. Plugged or
restricted exhaust
system.

7. Inspect and
replace as
necessary.

8. Faulty coil.

8. Refer to
REMOVAL .

9. Incorrect cam
timing.

9. Refer to Engine
Timing in this
article.

ENGINE MISSES
ON
ACCELERATION

1. Spark plugs dirty
or incorrectly
gapped.

1. (Refer to SPARK
PLUG ).

2. Dirt in fuel
system.

2. Clean fuel
system.

3. Burned, warped
or pitted valves.

3. Replace as
necessary.

4. Faulty coil.

4. Refer to
REMOVAL .

ENGINE MISSES
AT HIGH SPEED

1. Spark plugs dirty
or incorrectly
gapped.

1. (Refer to SPARK
PLUG ).

2. Faulty coil.

2. Refer to
REMOVAL .

3. Dirt or water in
fuel system.

3. Clean system and
replace fuel filter.

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

Fig. 2: Proper Tool Usage for Surface Preparation
Courtesy of CHRYSLER LLC

To ensure engine gasket sealing, proper surface preparation must be performed, especially with the use of
aluminum engine components and multi-layer steel cylinder head gaskets.

Never use the following to clean gasket surfaces:

Metal scraper (3).

Abrasive pad (1) or paper to clean cylinder block and head.

High speed power tool (1) with an abrasive pad or a wire brush.

1 - ABRASIVE PAD
2 - 3M ROLOC™ BRISTLE DISC
3 - PLASTIC/WOOD SCRAPER

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro