The AERA Technical Committee offers the following information regarding a head gasket design change on 2001-06 GM 6.6L Duramax diesel engines. Special surface cleaning procedures must be followed to allow a proper seal when using the new design head gaskets along with a change in the torque angle specification.
A mid-year design change was made to the head gasket of the 2006 Duramax diesel engine. This second generation head gasket will service all 2001-06 vehicles,
including those that were built with the first generation head gaskets. The second generation head gasket does require a lower head bolt torque angle specification as well as special cleaning methods of the gasket surface.
The second generation gasket can be visually identified by its riveted construction as opposed to the crimped design of the first generation gasket.
For vehicles that were equipped with the first generation head gasket, special attention must be given to the cleaning of the engine block and head gasket
surfaces when the second generation head gasket is to be used. The crimped areas of the first generation gasket may over time allow corrosion build-up where they contact the block and head surface areas.
Inspect the gasket sealing surface for corrosion, especially in the areas that were in contact with the crimped tabs of the first generation head gasket. For surfaces that have corrosion or pitting in them, wrap a piece of flat steel with 600 grit we grade sand paper. Use a moisture displacing lubricant (P/N 1052864 USA, P/N 89020803 CANADA) or equivalent to wet sand the block surface to remove any remaining gasket material or corrosion. Do not use any paper coarser than 600 grit.
Take care to keep the sanding block parallel to the block surface and evenly sand the sealing surface. Some areas of corrosion will still show a stain. Do not attempt to wet sand these areas down to a shiny metal surface. Change sanding paper as necessary and clean surface with brake parts cleaner along with the head bolt holes and cylinder bores.
The second generation head gasket requires a lower torque angle specification for the M12 bolts. The M8 bolt torque remains the same. M12 bolts should be torqued to the following specifications.
Step 1: 37 ft/lbs
Step 2: 59 ft/lbs
Step 3: 60 °
Step 3: 60 °
M8 Bolts should be torqued to 18 ft/lbs.
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