Dodge Nitro. Manual — part 108

1. Disconnect negative battery cable.

2. Remove upper intake manifold. See REMOVAL.

3. Remove cylinder head cover(s). See REMOVAL.

4. Remove rocker arm and shaft assembly. See REMOVAL.

5. Remove spark plugs.

6. Rotate the crankshaft clockwise, until the number 1 piston is at Top Dead Center (TDC) on the

compression stroke.

7. With air hose attached to spark plug adapter installed in number 1 spark plug hole, apply 620.5 to 689

kPa (90 to 100 psi) air pressure. This is to hold valves into place while servicing components.

8. Using Tool MD 998772A (1) with adapter 6527 (4) or equivalent, compress valve spring and remove

valve locks (5). Release tension on valve spring, remove retainer (5) and valve spring. See SPECIAL
TOOLS. . See Fig. 169.

9. Remove valve stem seal, if required. See REMOVAL.

10. Follow the same procedure on the remaining 5 cylinders using the firing sequence 1-2-3-4-5-6. Make

sure piston is at TDC in each cylinder of the valve spring that is being removed.

11. Remove spark plug adapter tool.

VALVE SPRING - CYLINDER HEAD OFF

1. Compress valve spring with valve spring compressor C-3422-D and adapter 6526. See SPECIAL

TOOLS.

2. Remove valve retaining locks. Release valve spring compressor. Remove valve spring retainer and valve

spring.

3. Remove valve stem seal assembly. See REMOVAL.

INSPECTION

VALVE SPRING - INSPECTION

2007 Dodge Nitro R/T

2007 ENGINE 4.0L - Service Information - Nitro

Fig. 170: Testing Valve Spring
Courtesy of CHRYSLER LLC

When valves have been removed for inspection, reconditioning or replacement, valve springs should be tested.
See Fig. 170. As an example; the compression length of the spring to be tested is 38.00 mm (1.496 in.). Turn
table of Tool C-647 until surface is in line with the 38.00 mm (1.496 inches.) mark on the threaded stud and the
zero mark on the front. Place spring over stud on the table and lift compressing lever to set tone device. Pull on
torque wrench until ping is heard. Take reading on torque wrench at this instant. Multiply this reading by two.
This will give the spring load at test length. Fractional measurements are indicated on the table for finer
adjustments. Refer to Engine Specifications to obtain specified height and allowable tensions. See
SPECIFICATIONS. Replace springs that do not meet specifications.

INSTALLATION

VALVE SPRING - CYLINDER HEAD OFF

1 - SPECIAL TOOL C-647

2007 Dodge Nitro R/T

2007 ENGINE 4.0L - Service Information - Nitro

Fig. 171: Valve, Valve Retaining Locks, Valve Spring Retainer, Valve Spring & Valve Seal/Valve Spring
Seat Assembly
Courtesy of CHRYSLER LLC

1. Install valves if removed.

2. Install valve stem seal/spring seat assembly (5) over valve guides on all valve stems. See Fig. 171. Ensure

that the garter spring is intact around the top of the rubber seal.

3. Place valve spring (color-coded end facing up) (4) and valve retainer into position.

1 - VALVE
2 - VALVE RETAINING LOCKS
3 - VALVE SPRING RETAINER
4 - VALVE SPRING
5 - VALVE SEAL AND VALVE SPRING SEAT ASSEMBLY

2007 Dodge Nitro R/T

2007 ENGINE 4.0L - Service Information - Nitro

Fig. 172: Spring Retainer, Garter Spring, Valve Spring Seat Top & Cylinder Head Surface
Courtesy of CHRYSLER LLC

4. Compress valve spring with valve spring compressor. Install locks and release tool. If valve and/or seat

are reground, measure the installed height of springs (B), make sure measurements are taken from
top of spring seat to the bottom surface of spring retainer . If height is greater than 38.75 mm (1.5256
in.), install a 0.762 mm (0.030 in.) spacer in head counterbore under the valve spring seat to bring spring
height back within specification. See Fig. 172.

SPRING -VALVE - CYLINDER HEAD ON

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

2007 Dodge Nitro R/T

2007 ENGINE 4.0L - Service Information - Nitro