Engine - Replacement Cylinder Head Modifications
Bulletin No.: 08-06-01-001Date: January 17, 2008
INFORMATION
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(TM) 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.
Refer to SI for all Disassembly and Assembly service procedures.
Service Procedure
Do not drill the guide while installed on the engine, metal fallout from drilling operation may cause consequential engine damage.
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.
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.
Install the larger guide bolt, P/N 11588725 (1) to the left upper timing chain guide.
Install the timing chain guide and secure the guide with the bolts.
Tighten
Tighten the timing chain guide to 10 N.m (89 lb in).
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.
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
Warranty Information (excluding Saab U.S. Models)
For vehicles repaired under warranty use the table.
Warranty Information (Saab U.S. Models)
For vehicles repaired under warranty, use the table.
Disclaimer