Cylinder Head: Installation

1. Clean the bolt threads and the bolt holes in the cylinder block.
   CAUTION: To avoid erroneous tightening of the bolts, clean out the bolt holes sufficiently by blowing with compressed air to eliminate engine coolant etc.
2. Apply a sufficient coat of engine oil to the washer and bolt thread.
3. Tighten all bolts to 40 N.m (4.1 kgf-m, 29.5 ft-lb) in alphabetical order.
4. Retighten all bolts to 95 N.m (9.7 kgf-m, 70.1 ft-lb) in alphabetical order.
   CAUTION: If the bolt make stick-slip sound during tightening, repeat the procedure from step (1)  . In this case, cylinder head gasket can be reused.
5. Loosen all the bolts by 180° in the reverse order of installing, and loosen them further by 180°.
6. Tighten all bolts to 10 N.m (1.0 kgf-m, 7.4 ft-lb) in alphabetical order.
7. Retighten all bolts to 30 N.m (3.1 kgf-m, 22.1 ft-lb) in alphabetical order.
8. Retighten all bolts to 60 N.m (6.1 kgf-m, 44.3 ft-lb) in alphabetical order.
9. Retighten all bolts by 80 - 90° in alphabetical order.
10. Retighten all bolts by 40 - 45° in alphabetical order.
    CAUTION: The tightening angle of the bolt should not exceed 45°.
11. Retighten bolts (a) and (b) by 40 - 45°.
    CAUTION: Make sure the total "tightening angle" of steps (10) and (11) does not exceed 90°.
    Fig 1: Tightening Sequence Of Cylinder Head Bolts

    Courtesy of SUBARU OF AMERICA, INC.

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