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For 1990-2009 cars only

LL8 Cylinder Head - Information on Service Replacement Cylinder Head Changes that Apply to 2006 and 2007 Model Years

Subject:LL8 Cylinder Head -- Information on Service Replacement Cylinder Head Changes that Apply to 2006 and 2007 Model Years

Models:2006-2007 Buick Rainier
2006-2007 Chevrolet TrailBlazer Models
2006-2007 GMC Envoy Models
2006-2007 Saab 9-7X
with Vortec™ 4.2L I-6 Engine (VIN S -- RPO LL8)



For 2006-2007, Inline 6 engines requiring a cylinder head replacement with P/N 89017826, technicians will notice that the left threaded bolt hole for the timing chain stationary guide upper mounting hole has been enlarged to 8 mm (0.31 in) and the fourth fuel rail mounting hole has been eliminated.

To install this replacement head on 2006 and 2007 vehicles, you must first remove the left timing chain stationary guide from the engine and enlarge the upper mounting hole on the guide to accept a new 8 mm bolt. You must also adjust the fourth injector fuel rail bracket tab for clearance.

Important: Refer to SI for all Disassembly and Assembly service procedures.

Service Procedure


    Object Number: 2048527  Size: SH

    Notice: Do not drill the guide while installed on the engine, metal fallout from drilling operation may cause consequential engine damage.

  1. Remove the left timing chain guide bolts and remove the timing chain guide from the vehicle. Refer to SI for oil pan and front cover removal.
  2. To accommodate the larger bolt to fit, enlarge the upper hole only in the left timing chain guide (1) by using a 5/16" drill bit.
  3. Install the larger guide bolt, P/N 11588725 (1) to the left upper timing chain guide.
  4. Install the timing chain guide and secure the guide with the bolts.
  5. Tighten
    Tighten the timing chain guide to 10 N·m (89 lb in).


    Object Number: 2048523  Size: SH

    Notice:  Do not pry on the fuel injectors or the fuel injector rail when adjusting the bracket. Refer to callout #1 in the fuel rail illustration as a rotating point to adjust the bracket using two pairs of pliers.

  6. To avoid the possibility of the injector rail bracket tab contacting the cylinder head and causing a noise or vibration issue, adjust the bracket tab to an angle similar to the one shown in the illustration above (1). Use two pairs of pliers and carefully rotate the bracket tab upwards.

Parts Information

Part Number

Description

Qty

11588725

Bolt, M8 X 1.25 X 35

1

Warranty Information (excluding Saab U.S. Models)

For vehicles repaired under warranty, use:

Labor Operation

Description

Labor Time

J0785

Guides, Timing Chain - Replace

Use Published Labor Operation Time

Warranty Information (Saab U.S. Models)

For vehicles repaired under warranty, use:

Labor Operation

Description

Failed Object

Fault/Reason

Location Code

Warranty Type

Repair/Action Code

Labor Time

2152402

Guides, Timing Chain - Replace

21524

00

0

01

01

Use Published Labor Operation Time