Document ID # 1206539

2002 Chevrolet Corvette

Engine Knock or Lifter Noise

(Replace O-Ring)
#02-06-01-038 - (12/02/2002)

2001-2002 Chevrolet Camaro

2001-2003 Chevrolet Corvette [Note: this means all LS6 engines]

2001-2002 Pontiac Firebird

2002-2003 Cadillac Escalade, Escaladc EXT

2000-2003 Chevrolet Suburban, Tahoe

2001-2003 Chevrolet Silverado

2002-2003 Chevrolet Avalanche

2000-2003 Chevrolet Yukon, Yukon XL

2001-2003 GMC Sierra

with 4.8L. 5.3L, 5.7L or 6.0L V8 Engine (VINs V. T. Z. G. S. N. U -- RPOs LS1, LS6, LR4, LM71, LQ9, LQ4)


Some customers may comment on an engine tick noise. Thc distinguishing characteristic of this condition is that it likely will have been present since new and is typically noticed within the first 161- 322 km (100-200 mi). The noise may often be diagnosed as a collapsed lifter. Additionally, the noise may be present at cold start and appear to diminish and then return as the engine warms to operating temperature. This noise is different from other noises that may begin to occur at 3219-4828 km (2000-3000 mi).


The O~ring seal between the oil pump screen and the oil pump may be cut causing aeration of the oil.


Inspect the O-ring seal and replace as necessary. Use the applicable part number listed below. Refer to the Engine Mechanical sub-section of the appropriate Service Manual.

Parts Information

Part Number Description Quantity
12557752 Seal-O/Pmp (O-ring) 1

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty use:

Labor Operation Description Labor Time
J0250 Pickup Tube and Screen - Replace 4.3 hrs

End of Bulletin #1206539

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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Creation Date: Friday, January 31, 2003
Last Modified: Friday, January 31, 2003
Copyright © Ray Smith, 2003