News Technical Service Bulletins

Chevrolet Says Vehicle May Have Wrong Cam

Order Reprints
Note arrows pointing to machined and cast rings. Compare the ring strategy order to the original engine’s camshafts.


This bulletin applies to 2010-2015 Chevy Camaro and 2015-2016 Colorado equipped with a 3.6L engine, 2007-2017 Equinox equipped with a 3.0 or 3.6L engine, 2007-2012 Malibu equipped with a 3.6L engine and 2009-2019 Traverse equipped with a 3.6L engine. 

Some dealers may experience a misfire immediately after installing a GM remanufactured HFV6 engine, usually limited to 1 bank or 1 cylinder. This is usually a rear cylinder (5 or 6) but could be any cylinder. The condition could be caused by the wrong camshaft being installed in the engine at the reman facility.

If you experience this concern, inspect the camshafts to ensure the correct camshaft is installed in each intake and exhaust position by comparing the ring strategy to either the engine that was removed (the best approach) or by the charts available in the service manual. 

Ring strategy camshaft identification is a series of rings along the camshaft that are either castings or castings that have been machined. There are five rings on each camshaft. 

Identification occurs by the order in which the machined or cast rings are on the camshaft. If you find one or both incorrect camshafts, replace with camshafts taken from the original engine (if not damaged) or with a new camshaft.

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