Ticking! Lifter Maybe?

kobarr · February 18, 2008

I have a 2003 Silverado I purchased new with the 4.8 engine. A few years ago it started ticking like a lifter with maybe only 10k on the motor (now has 40K) this noise would come and go. Now it is worse, ticks almost all the time but still runs fine. This is not the piston slap noise, I had a 02 Z71 that made that noise. This ticking happens when the engine is warm and maybe cold. A few years ago I took it to the dealer for some warranty work and mentioned the ticking and they said it was normal. They never even checked it. The lady in the service dept. said she could show me a bulletin on it and GM would not fix it. I'm getting worried about it now since it seems to be more often. Does this sound normal? Do I have anything to worry about? Thanks,

bobcat5544 · February 19, 2008

It could be a bad lifter(s) or it could be a back oil pump seal see bulletin below on the seal

Document ID# 1206539

2003 Chevrolet Chevy K Silverado - 4WD

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Subject: Engine Knock or Lifter Noise (Replace O-Ring) #02-06-01-038 - (12/02/2002)

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)

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

Correction

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

Qty

12557752

Seal-O/Pmp (O-ring)

(F and Y Cars)

1

12563963

Seal-O/Pmp (O-ring)

(C/K Trucks)

1