More ticking noise questions

[Nickn]

Hello all, long time reader but first time posting.

I have a 2003 Tahoe z71 with about 189000 that I bought about 4 months ago. Truck runs great except for a ticking noise that i noticed about a week ago coming from the around the bottom half of the engine on the passenger side.

I have done the following repairs since I bought it:
1.Exhaust gaskets
2. Fuel pump and fuel pressure regulator
3. Plugs and wires
All parts are GM/AC Delco

Oil pressure is 20 psi at idle and 40 while driving. Ticking moves with RPMs and is present hot and cold. No CEL. Per my scanner, all sensors (knock sensors, fuel trims, O2, etc) are reading within spec at hot idle.

From what I have read, this could be lifter tick. Is there a way I can determine for sure if this is the case?

Any insight would be greatly appreciated!

 

[02 Burb]

Its lifter tap, heres what it sounds like Click me

 

[Nickn]

Lifter Tap

Its lifter tap, heres what it sounds like Click me

Thanks for the reply 02 Burb. I was afraid that it may be lifter(s). Short of pulling the head and replacing and/or rebuilding the offending lifters, what can i do to reduce the tap? I hear mixed things about motor flush products (some say they work, others don't like them)

I will probably be either pulling the heads to replace the lifters/ cam or just rebuilding the whole engine early next year given the high mileage, etc but want to ensure it doesn't grenade on me until then.

I just don't have the time to do it now.

 

[Nickn]

Per a GM TSB, looks like an oil pump o-ring has to be replaced (ill prob just replace the pump)

2001-2003: Service Bulletin: Engine Knock or Lifter Noise
Subject: Engine Knock or Lifter Noise (Replace O-Ring)
Model and Year:
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)
Source: Chevrolet Service Bulletin
Bulletin Number: 02-06-01-038 - (12/02/2002)

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