Cylinder Head and Valves Removal and Installation

CYLINDER HEAD AND VALVES





REMOVAL AND INSTALLATION

Required Special Tools:
- MB991654: Cylinder Head Bolt Wrench (12)
- MD998772: Valve Spring Compressor
- MD998774: Valve Stem Seal Installer

Removal Service Points
<> Cylinder Head Bolts Removal





Using special tool MB991654, loosen the cylinder head bolts. Loosen each bolt evenly, little by little, by two or three steps.

<> Retainer Lock Removal

1. Set special tool MD998772 as illustrated to compress the valve spring. Remove the retainer lock.
2. Relieve the spring tension and remove the valve, retainer, spring, etc. Store removed valves, springs, and other parts, tagged to indicated their cylinder number and location for assembly.

Installation Service Points
>>A<< Valve Stem Seal Installation

CAUTION: The special tool must be used to install the valve stem seal. Improper installation could result in oil leaking past the valve guide.

1. Install the valve spring seat.
2. Using special tool MD998774, install a new valve stem seal.

>>B<< Valve Spring Installation

Install the valve spring with its ID color painted end (larger pitch side) upward (toward the valve spring retainer).

>>C<< Retainer Lock Installation

CAUTION: Do not compress the valve spring excessively. It can damage the stem seal.

1. Set special tool MD998772 as illustrated to compress the valve spring. Install the retainer locks.
2. Relieve the spring tension. Check that the retainer locks are seated correctly.

>>D<< Cylinder Head Bolt Installation

1. When the removed cylinder head bolts are to be reused, check that the shank length of each bolt meets the limit. If it exceeds the limit, replace the bolts.
Limit: 99.4 mm (3.91 inches)
2. Apply engine oil to the thread of the bolts and to the washers.

3. Using special tool MB991654 tighten the bolts to the specified torque 78 Nm (58 (ft. lbs.), using the tightening sequence shown.
4. Loosen all bolts fully in the reverse order of tightening.
5. Retighten the loosened bolts to 20 Nm (14 ft. lbs.) in the tightening sequence shown.

6. Make a paint mark across each bolt head and cylinder head.
7. Tighten the cylinder head bolts 90 degree angle in the specified order.

CAUTION:
- If the bolt is turned less than 90 degree angle, proper fastening performance may not be achieved. Be careful to turn each bolt exactly 90 degree angle.
- If the bolt is overtightened, loosen the bolt completely and then retighten it by repeating the tightening procedure from step 1.
8. Tighten the bolts another 90 degree angle in the same order as in step 7, and check that the paint marks on the cylinder head bolt are aligned with the paint marks on the cylinder head.