GM TSB Engine Knock Startup - Not a Filter Problem

[CapitalTruck]

I had blamed oil filters for this before. I guess it wasn't the lowly PF48E that was giving me fits (to be fair, it's happened some with the Mobil 1 filter also). I guess I'm back to the OEM PF48E that is the OE filter and cheaper. I had really thought this filter was the problem, however, this bulletin describes my situation to a "T". Only difference is the onset seems to be a little later. Maybe this applies to you as well:

# 01-06-01-028C: Engine Knock on Cold Start - (Apr 5, 2016)
Subject: Engine Knock on Cold Start

Models: 1999-2006 Chevrolet and GMC C/K Pickup and Utility Models
2002-2016 Cadillac Escalade Models
2007-2013 Chevrolet Silverado
2014 Chevrolet Silverado 1500
2015-2016 Chevrolet Silverado, Suburban, Tahoe
2007-2013 GMC Sierra
2007-2014 GMC Yukon Denali, Yukon XL Denali
2014 GMC Sierra 1500
2015-2016 GMC Sierra, Yukon Models
Equipped with 4.8L, 5.3L, 6.0L or 6.2L Gas Engine

Attention: This Bulletin also applies to any of the above models that may be
Export vehicles.

This Bulletin has been revised to update the Models section. Please discard Corporate Bulletin Number 01-06-01-028B.
Some of the above vehicles may exhibit an engine knock noise that begins in the first 19,000-24,000 km (12,000-15,000 mi) of use. The knock noise is most often noticed during initial start-up and typically disappears within the first 5-30 seconds (may last longer in extreme cold temperatures). The noise is usually more noticeable on the initial start-up when the temperature is below 10°C (50°F) and may be more pronounced on the first cold start following a long trip.
This noise may be caused by an interaction between carbon that has formed on the piston, the piston motion and the cylinder wall. GM Powertrain Engineering, and an analysis of engines with this condition, has confirmed that the noise is not detrimental to the performance, reliability or durability of the engine. THIS NOISE DOES NOT HAVE ANY EFFECT ON THE LONGEVITY OF ANY OF THE ENGINE COMPONENTS.
Important :
At this time, attempts to repair this condition by replacing the engine assembly or pistons are not recommended.

Please share the information found in this bulletin with customers who inquire about this condition. In the event they have additional questions or concerns, please advise your District Manager Aftersales (U.S.) (in Canada, District Manager - Customer Care and Service Process (DM-CCSP)

 

[splinter]

Originally Posted By: CapitalTruck
Models: 1999-2016 equipped with 4.8L, 5.3L, 6.0L or 6.2L Gas Engines

...piston motion and the cylinder wall...


Pretty clever that "GM Powertrain Engineering."

 

[crazyoildude]

This "knocking" some is piston slap has been around for a long time on those engines many with low mileage.. They sound like this at 20,000 miles and sound the same way at 220,000 miles.. Lemon law Lawyers win these cases all the time..

 

[Ramblejam]

"Just a FYI since I've done this I haven't noticed the startup engine knock at all. Has knocked like a rod gonna fly out since 20,000 miles on startup."

This is from a PM here where I was helping member Honda2003 with his 2001 GMC 5.3L (with over 200k on the clock).

Know what fixed the problem? http://www.kanolabs.com/engCle.html

 

[ZeeOSix]

Originally Posted By: GM Bulletin

This noise may be caused by an interaction between carbon that has formed on the piston, the piston motion and the cylinder wall.


Need to rig up a water vapor injection system, which will clean the carbon out big time.

 

[edwardh1]

I always wonder why this noise did not appear when they tested the engine.
They do test them don't they?

 

[JimPghPA]

Saved for future reference.

 

[KingCake]

How does carbon cause 5 seconds of piston slap, exactly? This sounds like CYA [censored]. Ford said the same thing with the 4.0 knocking back in the late 90s/early 2000s. Just carbon, no problems!!

 

[Lubener]

Originally Posted By: splinter
Originally Posted By: CapitalTruck
Models: 1999-2016 equipped with 4.8L, 5.3L, 6.0L or 6.2L Gas Engines

...piston motion and the cylinder wall...


Pretty clever that "GM Powertrain Engineering."


A.K.A. "Drunken Lunch Bunch".

 

[SteveSRT8]

we have been dealing with carbon knock here for decades now. It is often confused with piston slap, and many times the same engine exhibits both.

They still run well and last a looooong time...

 

[SteveSRT8]

And Ramblejam gave you the secret - Kreen!

 

[LeakySeals]

I do think oil and filter choices help. Faster flow and the best adbv you can get. The startup tick/knock/slap/whatever it was is basically gone from my 6.0. That and fixing a broken exhaust manifold bolt. But its not a fix for piston that's too small for the cylinder bore'

 

[Trav]

This has been a problem with some GM engines since the 90's, the Cadillac N* was notorious for it. Kreen works sort of but not as good as GM TEC the only real fix for them is a 2 part piston soak.
Part one is through the plug holes with GM top engine cleaner for a few hours then an application of the same through a central vacuum line letting it sit for a couple of hours more. Drive it hard and the black cloud under full load is amazing.
Good for another 20K, if you run it hard once in a while they will stay clean enough not to knock.

 

[Sayjac]

Just to clarify, it appears this tsb for engine start up knock does not supersede the one for the use of the 48E ecore oil filter, '#PIP5276D: SES Lamp P0521 Setting After An Oil Change And Or Low Oil Pressure Indicated On The Instrument Panel.' That one is still in effect and recommends using UPF48R AC Delco Ultra in place of the ecore should the conditions of that tsb arise.

As for topic, sounds like the common, 'just a characteristic' of those engines. As it doesn't directly affect me not much to comment on other than, King Cake makes interesting observations here 'imo'.

 

[bullwinkle]

Might be something to the carbon-the several '99-'02 5.7 Vortec powered vans I had never exhibited it, even up to almost 200K. Wonder why warming up makes it go away, though-that sounds like classic piston slap or wrist pin looseness?

 

[HerrStig]

Originally Posted By: ZeeOSix
Originally Posted By: GM Bulletin

This noise may be caused by an interaction between carbon that has formed on the piston, the piston motion and the cylinder wall.


Need to rig up a water vapor injection system, which will clean the carbon out big time.
And void your warranty "big time".

 

[LeakySeals]

also... I experienced a CEL for knock sensors a few months ago after cleaning engine. Was shocked that both were exposed to the elements for what looked like years. Replaced the sensors, harness, and that also made a big difference in the startup noises. And while the plastic intake manifold was off I gave the pistons a soak. pulling the intake was easier than pulling all the plugs. Not sure how much of a difference that made but it smoked for almost an hour on the highway.

 

[demarpaint]

17 years and counting............

 

[ZeeOSix]

Originally Posted By: HerrStig
Originally Posted By: ZeeOSix
Originally Posted By: GM Bulletin

This noise may be caused by an interaction between carbon that has formed on the piston, the piston motion and the cylinder wall.


Need to rig up a water vapor injection system, which will clean the carbon out big time.
And void your warranty "big time".


You mean the warranty on a car that doesn't have a warranty anymore. Water vapor injection isn't going to hurt anything, and will clean carbon off pistons and heads better than most other procedures. I doubt the vehicles in the newer year ranges of the TSB have enough miles to even exhibit this issue. Besides, even if they did, GM isn't going to "fix it" under warranty. They'll tell you that you the top end needs to be de-carboned and then charge you for it.