Cylinder Head Bolt Torqueing Sequence – 2015-2018 Subaru STI

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Bulletin Number: 02-179-18; Date: 10/12/18 Page 1 of 3 NUMBER: 02-179-18 DATE: 10/12/18 APPLICABILITY: 2015-2018MY STI SUBJECT: Cylinder Head Bolt Torqueing Sequence- UPDATED 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. 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 automotive products in a manner that is friendly to our environment and in accordance with all local, state and federal laws and regulations. Continued… 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. SERVICE INFORMATION BULLETIN ATTENTION: GENERAL MANAGER q PARTS MANAGER q CLAIMS PERSONNEL q SERVICE MANAGER q IMPORTANT – All Service Personnel Should Read and Initial in the boxes provided, right. © 2018 Subaru of America, Inc. All rights reserved. Bulletin Number: 02-179-18; Date: 10/12/18 Page 2 of 3 Continued… 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. Bulletin Number: 02-179-18; Date: 10/12/18 Page 3 of 3 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.

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