REMOVAL AND INSTALLATION

Removal steps <<A>> >>D<< 1. Cylinder head bolt 2. Cylinder head assembly 3. Cylinder head gasket <<B>> >>C<< 4. Retainer lock 5. Valve spring retainer >>B<< 6. Valve spring 7. Intake valve <<B>> >>C<< 8. Retainer lock 9. Valve spring retainer >>B<< 10. Valve spring 11. Exhaust valve <<C>> >>A<< 12. Valve stem seal 13. Valve spring seat <<C>> >>A<< 14. Valve stem seal 15. Valve spring seat 16. Intake valve guide 17. Exhaust valve guide 18. Intake valve seat 19. Exhaust valve seat 20. Cylinder head

Use the special tool Cylinder head bolt wrench (MB991653) to loosen the cylinder head bolts.

Compress the valve spring using the special tool Valve spring compressor (MD998772), then remove the retainer lock. note Store removed valves, springs and other parts, after putting to each of them a tag that identifies its cylinder No. or installation location.

Using pliers, remove the valve stem seal.

4. note Do not confuse the stem seals for intake valves with those for exhaust valves.

5. caution Do not reuse the valve stem seal. The special tool must always be used when installing the valve stem seal. Improper installation could result in oil leaks past the valve guide. Use the special tool Valve seal installer (MB991671) to install the stem seal on the valve guide. Use the stem of the valve to guide the stem seal.

Install each valve spring with the painted end toward the rocker arm.

Compress the valve spring using the special tool Valve spring compressor (MD998772), then install the retainer lock.

1.When reusing a cylinder head bolt, check that its nominal length (shank length) is not greater than the limit. If the limit is exceeded, replace the bolt. Limit: 103.2 mm 2.Apply engine oil to the threads and washer of the bolt.

3. note Use the special tool Cylinder head bolt wrench (MB991653) to tighten the bolts.

4.Tighten the bolts to 49 ± 2 N·m in the indicated sequence. 5.Loosen all the bolts completely. 6.Tighten the bolts again to a torque of 20 ± 2 N·m in the indicated sequence.

7. caution If the tightening angle is smaller than 90°, proper fastening performance could not be assured. Be sure to respect that angle. If the bolt is tightened to an angle greater than the specified angle, loosen the bolt completely and then retighten it beginning with the first step. Make paint marks on each bolt’s head and on the cylinder head. 8.Turn the bolts 90° in the tightening direction and in the indicated sequence. 9.Give another 90° turn in the tightening direction to each bolt, making sure that the paint mark on the bolt head and that on the cylinder head are on the same line.