Mitsubishi Evolution X. Manual - part 178

VALVE STEM SEAL

TSB Revision

ENGINE MECHANICAL

11A-43

VALVE STEM SEAL

REMOVAL AND INSTALLATION

M1112008100472

CAUTION

*Remove and assemble the marked parts in each cylinder unit.

Pre-removal operation
• Engine Room Under Cover Front A, B, Engine Room 

Under Cover Center and Engine Room Side Cover (RH) 

Removal (Refer to GROUP 51, Under Cover 

P.51-16

).

• Engine Oil Draining (Refer to GROUP 12, On-vehicle Ser-

vice 

− Engine Oil Replacement 

P.12-5

).

• Rocker Cover Assembly Removal (Refer to 

P.11A-25

).

• Engine Oil Pan Removal (Refer to 

P.11A-51

).

• Timing Chain Removal (Refer to 

P.11A-69

).

Post-installation operation
• Timing Chain Installation (Refer to 

P.11A-69

).

• Engine Oil Pan Installation (Refer to 

P.11A-51

).

• Valve Clearance Check (Refer to 

P.11A-10

).

• Rocker Cover Assembly Installation (Refer to 

P.11A-25

).

• Engine Oil Refilling (Refer to GROUP 12, On-vehicle Ser-

vice 

− Engine Oil Replacement 

P.12-5

).

• Engine Room Under Cover Front A, B, Engine Room 

Under Cover Center and Engine Room Side Cover (RH) 

Installation (Refer to GROUP 51, Under Cover 

P.51-16

).

AC704356

6

3

11

AC

7

12

13

1

4

5

10

9

14

N

N

2

8

15*

16*

17*

18*
19*

15*

16*

17*

18*

19*

18 ± 2 N·m
13 ± 2 ft-ib

Apply engine oil to all
moving parts before
installation.

12 ± 1 N·m
107 ± 8 in-lb  

17 ± 3 N·m
13 ± 2 ft-lb

to

30 ± 2 N·m
23 ± 1 ft-lb

12 ± 1 N·m
107 ± 8 in-lb  

Removal steps 

<<

A

>>

>>

G

<< 1.

Front camshaft bearing cap 
assembly

>>

F

<<

2.

Camshaft bearing

<<

B

>>

>>

E

<<

3.

Oil feeding camshaft bearing cap 
(exhaust side)

<<

B

>>

>>

E

<<

4.

Camshaft bearing cap (exhaust 
side)

<<

B

>>

>>

E

<<

5.

Camshaft bearing cap (exhaust 
side)

<<

B

>>

>>

E

<<

6.

Thrust camshaft bearing cap 
(exhaust side)

>>

F

<<

7.

Camshaft and camshaft sprocket 
assembly (exhaust side)

>>

F

<<

8.

Camshaft bearing

<<

B

>>

>>

E

<<

9.

Oil feeding camshaft bearing cap 
(intake side)

<<

B

>>

>>E<<

10. Camshaft bearing cap (intake side)

<<

B

>>

>>

E

<<

11. Camshaft bearing cap (intake side)

Removal steps (Continued)

VALVE STEM SEAL

TSB Revision

ENGINE MECHANICAL

11A-44

Required Special Tools:

• MD998772: Valve Spring Compressor

• MB992089: Retainer Holder C

• MB992090: Retainer Holder Attachment

• MB992085: Valve Stem Seal Pliers

• MD998737: Valve Stem Seal Installer

REMOVAL SERVICE POINTS

.

<<A>> FRONT CAMSHAFT BEARING CAP 
ASSEMBLY REMOVAL

CAUTION

Be careful not to drop the camshaft bearing.
Loosen the mounting bolts of front camshaft bearing cap in the 
order of number shown in the figure, and remove the front cam-
shaft bearing cap assembly.

.

<<

B

>>

>>

E

<<

12. Thrust camshaft bearing cap 

(intake side)

13. Camshaft and camshaft sprocket 

assembly (intake side)

14. Spark plug

<<

C

>>

>>

D

<<

15. Valve tappet

<<

D

>>

>>

C

<<

16. Valve spring retainer lock
17. Valve spring retainer

>>

B

<<

18. Valve spring

<<

E

>>

>>

A

<<

19. Valve stem seal

Removal steps (Continued)

AC506745

AD

1

2

3

4

Engine front

Front camshaft
bearing cap
assembly

VALVE STEM SEAL

TSB Revision

ENGINE MECHANICAL

11A-45

<<B>> OIL FEEDING CAMSHAFT BEARING 
CAP/CAMSHAFT BEARING CAP/THRUST 
CAMSHAFT BEARING CAP REMOVAL

CAUTION

When the camshaft bearing cap mounting bolts are loos-
ened at once, the mounting bolts jump out by the spring 
force and the threads are damaged. Always loosen the 
mounting bolts in four or five steps.
Loosen the mounting bolts of the camshaft bearing caps in the 
order of number shown in the figure in four or five steps, and 
remove the camshaft bearing caps.

.

<<C>> VALVE TAPPET REMOVAL

CAUTION

• Do not use pliers or other tools to remove the valve tap-

pets. Always remove them by hand.

• When reusing the removed valve tappet, it has to be 

installed in the same position as before. Be sure to put 
a tab that shows the original installation position on the 
valve tappet when storing it. 

Remove all of the valve tappets by hand.

.

AC506746

AC

1

1

2

2

3

3

4

4

5

5

6

6

7

7

8

8

Engine front

Camshaft bearing cap

Camshaft bearing cap

AC509270

AC

Valve tappet

VALVE STEM SEAL

TSB Revision

ENGINE MECHANICAL

11A-46

<<D>> VALVE SPRING RETAINER LOCK 
REMOVAL

1. Screw in special tool MB992090 to special tool MD998772 

and assemble special tool MB992089.

CAUTION

When removing the valve spring retainer lock, leave the 
piston of the cylinder in the TDC (Top Dead Center) posi-
tion. The valve may fall into the cylinder if the piston is not 
properly in the TDC position.
2. Install special tool MD998772 (with special tools MB992090 

and MB992089 attached) to the cylinder head and compress 
the valve spring. Then, remove the valve spring retainer 
lock.

.

<<E>> VALVE STEM SEAL REMOVAL

Use special tool MB992085 to grip the base of the stem seal 
(where the outside diameter is larger) securely, and remove it 
by twisting it to the left and right.

AC509271

AC

MD998772

MB992090

MB992089

AC608112 AB

Valve stem seal

MB992085