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 69 N.m (7.0 kgf-m, 50.9 ft-lb) in alphabetical order.
   CAUTION: If the bolt makes stick-slip sound during tightening, repeat the procedure from step  1. In this case, the 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 40 N.m (4.1 kgf-m, 29.5 ft-lb) in alphabetical order.
7. Retighten all bolts to 69 N.m (7.0 kgf-m, 50.9 ft-lb) in alphabetical order.
8. Loosen the bolts E, D, and A by 360° in this order.
9. Tighten the bolts A, D, and E to 10 N.m (1.0 kgf-m, 7.4 ft-lb) in this order.
10. Tighten the bolts A, D, and E to 30 N.m (3.1 kgf-m, 22.1 ft-lb) in this order.
11. Further tighten the bolts A, D, and E by 98 - 102° in this order.
12. Further tighten the bolt A by 123 - 127°.
13. Further tighten the bolts D and E by 78 - 82° in this order.
14. Loosen the bolts F, C, and B by 360° in this order.
15. Tighten the bolts B, C, and F to 10 N.m (1.0 kgf-m, 7.4 ft-lb) in this order.
16. Tighten the bolts B, C, and F to 30 N.m (3.1 kgf-m, 22.1 ft-lb) in this order.
17. Further tighten the bolts B, C, and F by 98 - 102° in this order.
18. Further tighten the bolt B by 123 - 127°.
19. Further tighten the bolts C and F by 78 - 82° in this order.

Fig 1: Cylinder Head Bolts (Tightening Sequence)

Courtesy of SUBARU OF AMERICA, INC.

Tightening torque: 

6.4 N.m (0.7 kgf-m, 4.7 ft-lb)