SB-01-06-01-028C

File in Section:
Bulletin No.:
Service Bulletin
Date:
06 - Engine
01-06-01-028C
April, 2016
INFORMATION
Subject:
Engine Knock on Cold Start
Models:
1999-2006 Chevrolet and GMC C/K Pickup and Utility Models
2002-2016 Cadillac Escalade Models
2007-2013 Chevrolet Silverado
2014 Chevrolet Silverado 1500
2015-2016 Chevrolet Silverado, Suburban, Tahoe
2007-2013 GMC Sierra
2007-2014 GMC Yukon Denali, Yukon XL Denali
2014 GMC Sierra 1500
2015-2016 GMC Sierra, Yukon Models
Equipped with 4.8L, 5.3L, 6.0L or 6.2L Gas Engine
Attention: This Bulletin also applies to any of the above models that may be Export vehicles.
This Bulletin has been revised to update the Models section. Please discard Corporate
Bulletin Number 01-06-01-028B.
Some of the above vehicles may exhibit an engine
knock noise that begins in the first 19,000-24,000♦km
(12,000-15,000♦mi) of use. The knock noise is most
often noticed during initial start-up and typically
disappears within the first 5-30♦seconds (may last
longer in extreme cold temperatures). The noise is
usually more noticeable on the initial start-up when the
temperature is below 10°C (50°F) and may be more
pronounced on the first cold start following a long trip.
This noise may be caused by an interaction between
carbon that has formed on the piston, the piston motion
and the cylinder wall. GM Powertrain Engineering, and
an analysis of engines with this condition, has
confirmed that the noise is not detrimental to the
performance, reliability or durability of the engine. THIS
NOISE DOES NOT HAVE ANY EFFECT ON THE
LONGEVITY OF ANY OF THE ENGINE
COMPONENTS.
Important: At this time, attempts to repair this
condition by replacing the engine assembly or pistons
are not recommended.
Please share the information found in this bulletin with
customers who inquire about this condition. In the
event they have additional questions or concerns,
please advise your District Manager Aftersales (U.S.)
(in Canada, District Manager - Customer Care and
Service Process (DM-CCSP).
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.
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