Had it happen to mine with 400 miles on it.Changed the pump.
Service Information
2012 GMC Truck Sierra - 4WD | Cheyenne, Sierra, Silverado VIN C/K Service Manual | Document ID: 2768732
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#PIP4978E: Tick Noise Cold or After 10 To 15 Minutes Of Engine Run Time It May Also Happen After A Coast Down At Operating Temperature **DO NOT REPLACE LIFTERS** - (Feb 6, 2012)
Subject:
Tick Noise Cold or After 10 To 15 Minutes Of Engine Run Time It May Also Happen After A Coast Down At Operating Temperature **DO NOT REPLACE LIFTERS**
Models:
2011 - 2012 Chevrolet Camaro
2011 - 2012 Chevrolet Corvette
2011 - 2012 Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe, Colorado
2011 - 2012 Cadillac Escalade
2011 - 2012 GMC Savana, Sierra, Yukon, Canyon
2011 - 2012 Cadillac CTS-V
Built with any of the following V8 Engine RPO Codes:
4.8L - L20
5.3L - LC9, LH9, LMG,
6.0L - L96
6.2L - L9H, LSA, LS3, L94, L99, LS9
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This PI was superseded to update specs along with Silao built engines. Please discard PIP4978D.
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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
A dealer may encounter a customer's concern of a lifter tick type noise that occurs cold at idle or 10 to 15 minutes after a cold start. It may also happen after a coast down at operating temperature (could happen at any time).
Typically the vehicle will have lower mileage; however, we have seen cases as high as 6k mi.
This may be a single lifter or multiple lifters making noise.
The oil pump may be aerating the oil when the engine is hot causing the lifters to make noise.
This would only apply to vehicles built between 4/1/11 and 11/1/11.
Except for vehicles built with Silao built engines. Silao uses a different supplier.
Note: Also includes replacement engines build in this time frame.
Recommendation/Instructions:
Do not replace the lifters for this concern.
Recommend to replace the oil pump for this concern of an engine tick noise.
Use current parts listed in GM parts catalog.
The new pump should be checked before it is installed. New pump may have the concern.
The oil pump can be checked by using a .002" or .050 mm feeler gauge (as shown below). If the feeler gauge will fit between the cover and the pump housing it should be replaced pump.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
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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