#PIP4156A: Possible Broken Rocker Arm On LS7 Engine - keywords cam camshaft DTC engine misfire miss noise push pushrod rattle SES tick valve Z06 - (Aug 29, 2007)
Subject: Possible Broken Rocker Arm On LS7 Engine
Models: 2007 Chevrolet Corvette Equipped with the 7.0L LS7 engine
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This PI was superseded to update Recommendation/Instructions. Please discard PIP4156.
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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
The customer concern may be an upper engine tick noise, or needle bearings found in the oil pan during an oil change.
Recommendation/Instructions:
If a dealer encounters an engine tick noise, or rocker arm needle bearings were found during an oil change, inspect all the rocker arms. If a damaged rocker arm is found, replace only the broken arm. Replacing the whole set of rocker arms is not necessary.
During the repair the technician may be trying to retrieve all of the needle bearings that were lost. Needle bearings may be found in cylinder head oil drains or oil pan. Clean the drains to retrieve the needle bearings, and replace only the damaged rocker arm.
Notie: The diameter of the needle bearing is larger then the oil pump pickup screen mesh. A needle bearing cannot be pulled into the oil 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.
