They still have a bulletin for lifter tick or possible cam lobe damage. I've put several lifters in and have seen lots of AFM lifter failures. Some have had cam lobe damage too. The ones with that usually the noise doesn't go away when warm. Even had a lobe so messed up that is stops the roller on the lifter from turning and will make it squeal thats sounds just like belt noise.

 

Thanx for the info Scooter.
I started it this morning in about 30 f temp and it sounds like a diesel for about 5 minutes.
It still makes noise once up to temp but you have to listen for it.

The noise it makes is a tap tap tap, metallic noise, goes with rpm of course.

What does a bad lifter sound like??

 

Lifter will sound like a hard rattle like marbles in a tin can but with a distinct metallic sound.

Magnuson moss is your friend it has to be proven that the tune caused a direct related failure. Tune wont lunch a lifter.

 

FWIW my truck has had lifter tap since I got it and it hasn't caused any problems so far. Mine does the same thing too, pretty audible at startup but you have to listen for it once it's warm. I don't know anything about the L92 though.

 

same here! in my 4.8 and in my boss's 08' 4.8.

 

Some L92's wiped cam lobes... The tick is different than piston slap thats for sure

 

I think I'll take the plugs out and spray some c/c cleaner in, let it side for a few hours,
crank it over to blow the crap out and put the plugs back in.
If the noise goes away, that should tell me if it's piston or valve train noise.
If it's piston noise, not much to do about it, if it's valve train noise, I'll ask them to fix it.

 

Well, I did the combustion chamber cleaning today and no improvement.
Does that tell us anything.

 

Here is my experience,this 6.2 new had a dead silent valvetrain,the day I tossed on the ARHs, a sound appeared,slight ticking like my old 2000 5.3 I bought new,the slightly lose valve lash sound was always there until I yanked it out for a mild 6.0 at 40K mi.

Any chance the noise came after your headers went on and you just noticed?

I know if I took the headers off went back stock I would not have the slight lifter tic noise

 

Definitely not exhaust, 100% sure.
I put the headers on within a week of getting the truck and there are no gasket leaks or cracked welds.

The issue with GM will be the tune history.
If they look, which they are supposed to for internal engine issues they will see the tune changes and can deny me warranty.
I know the service manager and could simply ask him how they would handle but that would be admitting quilt without them looking into it.

It is almost sounding like a wrist pin now.