Dodge Nitro. Manual — part 14

Fig. 46: Bloc-Chek-Kit C-3685-A
Courtesy of CHRYSLER LLC

AIR INTAKE SYSTEM

CLEANER-AIR ELEMENT

REMOVAL

REMOVAL

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

Fig. 47: Air Cleaner Element - 3.7L
Courtesy of CHRYSLER LLC

Housing removal is not necessary for element (filter) replacement.

1. Pry up spring clips (4) from front of housing cover (spring clips retain cover to housing). See Fig. 47.

2. Release housing cover from 4 locating tabs located on rear of housing, and remove cover.

3. Remove air cleaner element (filter) from housing.

1 - AIR INTAKE HOSE
2 - HOSE CLAMP
3 - COVER
4 - CLIPS (2)

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

4. Clean inside of housing before replacing element.

INSTALLATION

INSTALLATION

1. Install element into housing.

2. Position housing cover into housing locating tabs.

3. Pry up spring clips and lock cover to housing.

If any air filter, air resonator, air intake tubes or air filter housing clamps had been loosened or removed, tighten
them to 5 N.m (40 in. lbs.)

CYLINDER HEAD - LEFT

DESCRIPTION

VALVE GUIDES

The valve guides are made of powered metal and are pressed into the cylinder head. The guides are not
replaceable or serviceable, and valve guide reaming is not recommended. If the guides are worn beyond
acceptable limits, replace the cylinder heads.

DIAGNOSIS AND TESTING

HYDRAULIC LASH ADJUSTER

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 cylinder head. Low speed running up to 1 hour may be required.

3. 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 in cylinder head gasket or the 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 maximum extension and still leaves lash in the system.

10. Oil leak or excessive cam bore wear in cylinder head.

11. Faulty lash adjuster.

Check lash adjusters for sponginess while installed in cylinder head and cam on camshaft at base

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

circle. Depress part of rocker arm over adjuster. Normal adjusters should feel firm when pressed
quickly. When pressed very slowly, lash adjusters should collapse.

Remove suspected lash adjusters, and replace.

Before installation, make sure adjusters are full of oil. This can be verified by little plunger travel
when lash adjuster is depressed quickly.

CYLINDER HEAD GASKET

A cylinder head gasket leak can be located between adjacent cylinders or between a cylinder and the adjacent
water jacket.

Possible indications of the cylinder head gasket leaking between adjacent cylinders are:



Loss of engine power



Engine misfiring



Poor fuel economy

Possible indications of the cylinder head gasket leaking between a cylinder and an adjacent water jacket are:



Engine overheating



Loss of coolant



Excessive steam (white smoke) emitting from exhaust



Coolant foaming

CYLINDER-TO-CYLINDER LEAKAGE TEST

To determine if an engine cylinder head gasket is leaking between adjacent cylinders, follow the procedures in
Cylinder Compression Pressure Test. See DIAGNOSIS AND TESTING. An engine cylinder head gasket
leaking between adjacent cylinders will result in approximately a 50 - 70% reduction in compression pressure.

CYLINDER-TO-WATER JACKET LEAKAGE TEST

VISUAL TEST METHOD

With the engine cool, remove the coolant pressure cap. Start the engine and allow it to warm up until thermostat
opens.

If a large combustion/compression pressure leak exists, bubbles will be visible in the coolant.

COOLING SYSTEM TESTER METHOD

WARNING:

USE EXTREME CAUTION WHEN THE ENGINE IS OPERATING WITH
COOLANT PRESSURE CAP REMOVED.

WARNING:

WITH COOLING SYSTEM TESTER IN PLACE, PRESSURE WILL BUILD UP

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro