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Engine Lubrication: All Technical Service Bulletins Engine – Knocking or Lifter Noise File In Section: 06 – Engine/Propulsion System Bulletin No.: 02-06-01-038 Date: December, 2002 TECHNICAL Subject: Engine Knock or Lifter Noise (Replace 0-Ring) Models: 2001-2002 Chevrolet Camaro 2001-2003 Chevrolet Corvette 2001-2002 Pontiac Firebird 2002-2003 Cadillac Escalade, Escalade EXT 2000-2003 Chevrolet Suburban, Tahoe 2001-2003 Chevrolet Silverado 2002-2003 Chevrolet Avalanche 2000-2003 GMC 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 LR4, LM7, L59, LS1, LS6, LQ9, LQ4) Condition Some customers may comment on an engine tick noise. The 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). Cause The 0-ring seal between the oil pump screen and the oil pump may be cut, causing aeration of the oil. Correction
