Operation CHARM: Car repair manuals for everyone.
Home >> Subaru >> 2005 >> Impreza F4-2.5L SOHC >> Repair and Diagnosis >> Specifications >> Mechanical Specifications >> Engine >> Cylinder Head Assembly >> System Specifications
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

System Specifications

Cylinder Head

Use new cylinder head gaskets.
Tighten the cylinder head bolts.
Tighten all bolts 29 Nm (3.0 kgf-m, 22 ft. lbs.) in alphabetical sequence.
Then tighten all bolts 69 Nm (7.0 kgf-m, 51 ft. lbs.) in alphabetical sequence.
Back off all bolts by 180° in reverse order of installation, and back them off again by 180°.
Tighten all bolts 42 Nm (3.9 kgf-m, 31 ft. lbs.) in alphabetical sequence.
Tighten all bolts 80° - 90° in alphabetical sequence.
Tighten all bolts 40° - 45° in alphabetical sequence.

CAUTION: Do not tighten the bolts more than 45°.





Further tighten bolts (a) and (b) 40°- 45°

CAUTION: Ensure the total re-tightening angle of the step (6) and (7) does not exceed 90°.


Cylinder Head
Surface warpage limit (mating with cylinder block) 0.03 mm (0.001 inch)
Grinding limit 0.1 mm (0.004 inch)
Standard height 97.5 mm (3.84 inch)


Cam Sprocket Tightening Torque 78 Nm (8.0 kgf-m, 57.9 ft. lbs.)
pro multis · About Operation CHARM