Cylinder Head Bolt Hole Thread Repair

WARNING: This page is about a different variant/trim than selected.

Fig 1: Identifying Cylinder Head Bolt Hole Thread Repair Kit Components
Courtesy of GENERAL MOTORS COMPANY

The cylinder head bolt hole thread repair kit consists of the following items:
- EN-42385-51 The drill (1)
- EN-42385-52 The tap (2)
- EN-42385-53 The installer (3)
- EN-42385-57 The sleeve (4)
- EN-42385-55 The alignment pin (5)
- EN-42385-54 The bushing (6)
- EN-42385-56 The bolts (7)
- J-42385-301 The fixture plate (8) (Part of J-42385-300 Fixtures and Hardware Kit
Courtesy of GENERAL MOTORS COMPANY

WARNING:
Refer to Safety Glasses Warning .
NOTE:
- The use of a cutting type fluid GM P/N 1052864 (Canadian P/N 992881), WD 40®, or equivalent, is recommended when performing the drilling and tapping procedures.
- Driver oil MUST be used on the installer driver tool.
- The tool kits are designed for use with either a suitable tap wrench or drill motor.
Install the fixture plate (3), bolts (1), and bushing (2) onto the engine block deck.

Position the fixture plate and bushing over the hole that is to be repaired (4).
Courtesy of GENERAL MOTORS COMPANY

Position the alignment pin (1) through the bushing and into the hole.
With the alignment pin in the desired hole, tighten the fixture retaining bolts (2).
Remove the alignment pin from the hole.
Courtesy of GENERAL MOTORS COMPANY

CAUTION:
For the hole on the upper front corner of cylinder #1 (Left Cylinder Bank), install EN-42385-57 sleeve onto the drill. The depth of this hole is shallower than the others. If the sleeve is not used, damage to the engine block will occur.

Install the sleeve (2) onto the drill (1).
Courtesy of GENERAL MOTORS COMPANY

NOTE:
During the reaming process, it is necessary to repeatedly remove the drill and clean the chips from the hole.

Drill out the threads of the damaged hole.

Drill the hole until the stop collar of the drill bit or the sleeve contacts the bushing.
Using compressed air, clean out any chips.
Courtesy of GENERAL MOTORS COMPANY

Using a tap wrench, tap the threads of the drilled hole.
Courtesy of GENERAL MOTORS COMPANY

For the hole on the upper front corner of cylinder #1 (Left Cylinder Bank) only, rotate the tap into the hole until the first mark (1) on the tap aligns with the top of the drill bushing (3).

For all other cylinder head bolt holes, rotate the tap into the hole until the second mark (4) on the tap aligns with the top of the drill bushing (3).
Remove the fixture plate (2), bushing (3), and bolts.
Using compressed air, clean out any chips.
Spray cleaner GM P/N 12346139, GM P/N 12377981 (Canadian P/N 10953463), or equivalent, into the hole.
Using compressed air, clean any cutting oil and chips out of the hole.
Courtesy of GENERAL MOTORS COMPANY

NOTE:
Do not allow oil or foreign material to contact the OD of the insert.

Lubricate the threads of the installer tool (2) with the driver oil (1).
Courtesy of GENERAL MOTORS COMPANY

Install the insert (2) onto the driver tool (1).
Courtesy of GENERAL MOTORS COMPANY

Apply threadlock LOCTITE™ 277, J-42385-109 (1), or equivalent, to the insert OD threads (2).
Courtesy of GENERAL MOTORS COMPANY

Install the insert and driver (1) into the hole.

For the hole on the upper front corner of cylinder #1 (Left Cylinder Bank) only, rotate the driver tool until the lower mark on the driver tool aligns with the deck surface of the engine block.

For all other cylinder head bolt holes, rotate the driver tool until the upper mark on the driver tool aligns with the deck surface of the engine block.
1. Rotate the driver tool until the upper mark on the driver tool aligns with the deck surface of the engine block.
2. The installer tool will tighten up before screwing completely through the insert. This is acceptable. You are forming the bottom threads of the insert and mechanically locking the insert to the base material threads.