This bulletin is being revised to bring attention to the Set Gap Per Vehicle Specification on the ACDelco® Iridium Spark Plug Boxes. Please discard Corporate Bulletin Number 03-06-04-060 (Section 06 -- Engine/Propulsion System).


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• A new spark plug has been released for use in the above vehicles. The new spark plug has an Iridium tip instead of the current Platinum tip. Due to the different tip design, the gap of the spark plug has also changed.

• The new spark plug, P/N 12571164 with AC Delco P/N 41-985, is gapped to 1.01 mm (0.040 in) when the spark plug is made.


Notice: The spark plug gap is set during manufacturing and should not be changed or damage to the spark plug may result. Any new spark plug found to not be properly gapped should not be used.