Dodge Nitro. Manual — part 107

3. For spark plug tube (1) seal replacement, see REMOVAL).

4. Install cylinder head cover(s). See INSTALLATION

SEAL -VALVE STEM

REMOVAL

SEAL -VALVE STEM

Fig. 166: Removing Valve Stem Seals By Using Valve Stem Seal Tool
Courtesy of CHRYSLER LLC

1. Remove valve spring. See REMOVAL.

2. Remove valve stem seals by using a valve stem seal tool. See Fig. 166.

INSTALLATION

SEAL -VALVE STEM

1 - VALVE SEAL TOOL
2 - VALVE STEM

2007 Dodge Nitro R/T

2007 ENGINE 4.0L - Service Information - Nitro

Fig. 167: Checking Valve Tip Height & Valve Spring Installed Height
Courtesy of CHRYSLER LLC

1. The valve stem seal/valve spring seat should be pushed firmly and squarely over the valve guide using the

valve stem as guide. Do Not Force seal against top of guide. When installing the valve retainer locks,
compress the spring only enough to install the locks.

2. Install valve spring. See INSTALLATION.

SPRING -VALVE

DESCRIPTION

1 - SPRING RETAINER
2 - GARTER SPRING
3 - VALVE SPRING SEAT TOP
4 - CYLINDER HEAD SURFACE

CAUTION: Do not remove garter spring (2) around the seal at the top of the

valve stem seal. See Fig. 167.

2007 Dodge Nitro R/T

2007 ENGINE 4.0L - Service Information - Nitro

VALVE SPRING

Fig. 168: Valve Spring Identification
Courtesy of CHRYSLER LLC

The valve springs are made from chrome silicon alloy wire and incorporate a "bee-hive" design. Valve spring
retainers and locks are common from valve-to-valve. The valve spring seat is integral with the valve stem oil
seal, which incorporates a garter spring to maintain consistent lubrication control to the valve stem.

The valve springs are unique for intake compared to exhaust. Both have different lengths and are wound in
opposite directions. The valve springs are color coded, intake spring is right hand coil direction with orange dye
on the top coils, and the exhaust spring is left hand coil direction with a yellow or white dye on the top coils.
See Fig. 168.

The exhaust spring with the white dye on the top of the coils has an increased open and closed load when
compared to the exhaust spring with the yellow dye. A yellow and a white exhaust valve spring should never
be used on a single forked rocker arm. Color coated exhaust springs should always be used in pairs for a forked
exhaust rocker springs.

OPERATION

VALVE SPRING

1 - YELLOW OR WHITE DYE
2 - ORANGE DYE

2007 Dodge Nitro R/T

2007 ENGINE 4.0L - Service Information - Nitro

The valve spring returns the valve against its seat for a positive seal of the combustion chamber.

REMOVAL

VALVE SPRING - CYLINDER HEAD ON

Fig. 169: MD 998772A, Spark Plug Tubes, Cylinder Head, 6527 - Adaptor & Valve Spring Retainer
Courtesy of CHRYSLER LLC

1 - MD 998772A
2 - SPARK PLUG TUBES
3 - CYLINDER HEAD
4 - 6527 - ADAPTOR
5 - VALVE SPRING RETAINER

2007 Dodge Nitro R/T

2007 ENGINE 4.0L - Service Information - Nitro