02-179-18

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SERVICE MANAGER
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SERVICE INFORMATION BULLETIN
APPLICABILITY:
2015-2018MY STI		
SUBJECT:
		
Cylinder Head Bolt Torqueing
Sequence- UPDATED
NUMBER: 02-179-18
DATE: 10/12/18
INTRODUCTION:
This Service Information Bulletin announces a change to the procedure and sequence used for
torqueing the cylinder head bolts on the EJ25 turbocharged engine used in the 2015-2018MY STI.
SERVICE PROCEDURE / INFORMATION:
REMINDER: Customer satisfaction and retention starts with performing quality repairs.
The procedures for torqueing the cylinder head bolts have changed as outlined below. Always refer
to the applicable Service Manual and review the full requirements of the repair being performed. The
Service Manual procedures contain information critical to performing an effective repair the first time
and every time. This includes but is not limited to: important SAFETY precautions, proper inspection
criteria, necessary special tools, required processes and related one-time-use parts needed for a
complete and lasting repair.
Step 1: Preparation:
IMPORTANT NOTE: To achieve accurate cylinder head bolt torque, a quality torque wrench and a
torque angle gauge are both required. If the torque wrench or angle gauge has not been calibrated at
least once in the prior 6 months, a calibration check should be completed. The RH and LH sequences
are provided in the images below. In addition:
a) Always clean the cylinder head bolt threads and the bolt holes in the cylinder block before
proceeding with cylinder head installation.
b) While wearing eye protection, blow out all the bolt holes in the block using compressed air.
c) Always coat the head bolt threads and the head bolt washers thoroughly with engine oil.
d) Always use a NEW cylinder head gasket.
Continued...
CAUTION: VEHICLE SERVICING PERFORMED BY UNTRAINED PERSONS COULD
RESULT IN SERIOUS INJURY TO THOSE PERSONS OR TO OTHERS.
Subaru Service Bulletins are intended for use by professional technicians ONLY. They
are written to inform those technicians of conditions that may occur in some vehicles,
or to provide information that could assist in the proper servicing of the vehicle. Properly
trained technicians have the equipment, tools, safety instructions, and know-how to
do the job correctly and safely. If a condition is described, DO NOT assume that this
Service Bulletin applies to your vehicle, or that your vehicle will have that condition.
Bulletin Number: 02-179-18; Date: 10/12/18
Subaru of America, Inc. is
ISO 14001 Compliant
ISO 14001 is the international standard for
excellence in Environmental Management
Systems. Please recycle or dispose of
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to our environment and in accordance with all
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Page 1 of 3
Step 2: Install the cylinder head onto the block while being careful to not scratch any of the
machined mating surfaces.
Step 3: Tighten all bolts to 40 Nm (29.5 ft. lbs.) in alphabetical order (as shown in the drawing
below see letters A to F).
Step 4: Re-tighten all bolts to 69 Nm (50.9 ft. lbs.) in alphabetical order.
**VERY IMPORTANT: If the bolts make a stick-slip sound (Click, Creak or Squeak) or don’t feel
like they are tightening smoothly, repeat a), b) and c) as outlined in Step 1. (In this case, the cylinder
head gasket can be reused.)
Step 5: Loosen all bolts by 180° in reverse order of tightening (F to A) then loosen further by
another 180° (F to A).
Step 6: Tighten all bolts to 40 Nm (29.5 ft. lbs.) in alphabetical order.
Step 7: Retighten all bolts to 69 Nm (50.9 ft. lbs.) in alphabetical order.
Step 8: Loosen bolts E, D, and A by 360° in this specific order.
Step 9: Tighten bolts A, D, and E to 10 Nm (7.4 ft. lbs.) in this specific order.
Step 10: Tighten bolts A, D, and E to 30 Nm (22.1 ft. lbs.) in this specific order.
Step 11: Further tighten bolts A, D, and E by 98 - 102° in this specific order.
Step 12: Further tighten bolt A by 123 - 127°.
Step 13: Further tighten bolts D and E by 78 - 82° in this specific order.
Step 14: Loosen bolts F, C, and B by 360° in this specific order.
Step 15: Tighten bolts B, C, and F to 10 Nm (7.4 ft. lbs.) in this specific order.
Step 16: Tighten bolts B, C, and F to 30 Nm (22.1 ft. lbs.) in this specific order.
Step 17: Further tighten bolts B, C, and F by 98 - 102° in this specific order.
Step 18: Further tighten bolt B by 123 - 127°.
Step 19: Further tighten bolts C and F by 78 - 82° in this specific order to complete the procedure.
Continued...
Bulletin Number: 02-179-18; Date: 10/12/18
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IMPORTANT REMINDERS:
•
SOA strongly discourages the printing and/or local storage of service information as
previously released information and electronic publications may be updated at any time.
•
Always check for any open recalls or campaigns anytime a vehicle is in for servicing.
•
Always refer to STIS for the latest service information before performing any repairs.
Bulletin Number: 02-179-18; Date: 10/12/18
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