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