The engine in my truck has developed a noticable tap, quite loud when cold and still audible when warmed up.
Sounds like a valve train noise to me and seems to run ok.
Went to the dealer today and they basically said it's a normal LS engine noise.
I disagree. I had a 2000 that had piston slap, an 04, 07 and 08, none of which were noisey.
They said they would log my concern and if something breaks, they will fix it.
I would rather not break it in the first place.

Any know issues with 6.2 engine noise, it is not displacement on demand equipped.
I checked TSB's today and didn't find anything.

 

Maybe the 6.2 has the same issue as the 6.0 . LIFTERS

 

could be, but I thought that was for DOD equipped engines, mine is not.
Do you know different?

 

The TSB only applys to the AFM engines but you could still have a bad lifter or cam lobe. Have you checked for exhaust leaks or identified which side its coming from?

 

It is for sure, not exhaust.
Can't really hear the noise unless driving so it's hard to say where exactly the noise is coming from.
I am taking it to a bud's engine shop monday for him to have a listen.
Depending on what he says, I'll taking back to the dealer and insist they look atittle closer.

It has only 12k miles.
The dealer said it was piston noise and if I did a combustion chamber cleaning the noise would go away and come back in 8-10k miles.

I may do a cleaning just the prove or un-prove what he says , but I don't want a bunch of crap in my cats from a chamber cleaning.

The engine shop guy says he has seen them knock bad enough the knock sensors are rolling back timing.

 

Get a catch can setup for the PCV system to help prevent all that buildup on the pistons. Have you ever looked inside your intake? Tons of oil in there, so I feel thats the place to start regarding getting rid of the carbon buildup.

 

Are you concerned at all that if you dealer said well maybe it has something wrong with it.They tear it down and repair or replace parts and when you pick it up you have a bill for a few thousand bucks.They say we went reflash the ECM and we discovered its not stock and has been modified so GM voided the warrenty.they wont pay us so you have to if you want your truck back.

 

yeppers,
if it's valve train, it would probably not be an issue.
Internal engine is beyond what the local dealer is able to ok for warranty and Gm will look
at the calibtation history.
It has the stock tune now with the header codes turned off, but if the look they will find the changes.

 

I think it is valvetrain noise. My wife's Yukon has the same noise on start up but goes away when warm. I would have to check further but I thought the 6.2 have all the AFM hardware but not be used or tuned out from the factory. Let me see if I can find the bulletin for it.

 

Nevermind....I just looked and the early 6.2 had the AFM hardware but was disabled. Your 6.2 wouldn't have it.