Silverado 3500 2WD V8-6.6L DSL Turbo VIN 2 (2004)
Cylinder Head Bolts: Technical Service Bulletins
Diesel Engine - New Cyl. Head Gasket/Head Bolt Torque
INFORMATION
Bulletin No.: 06-06-01-006C
Date: October 30, 2009
Subject: Information on 6.6L LBZ, LB7, LLY Duramax(R) Diesel Engine Cylinder Head Gasket Design Change - New Head Gasket Part Numbers and
Head Bolt Torque Specifications
Models:
2001-2006 Chevrolet Silverado
2003-2006 Chevrolet Kodiak C4500/5500 Series
2006 Chevrolet Express
2001-2006 GMC Sierra
2003-2006 GMC TopKick C4500/5500 Series
2006 GMC Savana
with 6.6L Duramax(R) Diesel Engine (VINs D, 1, 2 - RPOs LBZ, LB7, LLY)
Supercede:
This bulletin is being revised to remove the Warranty Information. Please discard Corporate Bulletin Number 06-06-01-006B (Section 06 -
Engine/Propulsion System).
Important
If a cylinder head gasket is found to be absent of thickness grade markings, refer to Service Bulletin 07-06-01-009 for gasket identification.
A mid-year design change was made to the head gasket of the 2006 Duramax Diesel engine in December, 2005. This second generation gasket will
service all 2001-2006 vehicles, including those with engines built using first generation gaskets. The second generation gasket will require a lower head
bolt torque angle specification as well as special cleaning methods of the gasket surfaces.
Gasket Identification
The second generation gasket can be visually identified by its riveted construction, as opposed to the crimped design of the first generation gasket.
Second Generation Head Gasket (Riveted Construction)
Refer to the above illustration number (1) showing riveted construction.
First Generation Head Gasket (Crimped Construction)
Refer to the above illustration number (1) showing crimped construction.
Special Cleaning Requirements
For 2001-2006 vehicles produced with the first generation head gasket, special attention must be given to the cleaning of the engine block and cylinder
head surfaces when servicing with a second generation gasket. The crimped areas (1) on the first generation gasket may, over time, allow corrosion
buildup where they contact the block and cylinder head surfaces. The second generation gasket has raised ribs that seal at these crimped areas (1). A
special cleaning procedure is required to ensure proper sealing.
