My 6.0L has the cold start/warm start/any start knock from hell.....

This is the ever so common knock/problem that GM has a service bulletin about and such. I have bitched and complained to my dealer and GM trying to get a new 04 motor that has the issue fixed. It is VERY annoying and I can't seem to find a cure to get it to stop. My dad and I were talking (he has an 01 C3 that knocks as well) and he just bought his truck of lease. My truck is also on a GMAC buy, so it will be mine for a while.

Now my concern....
What will happen to the motor eventually...will the knocking issue cause a bad/catastraphic failure of some sort inside the motor? It just kinda worries me some that something major may go wrong with the motor some years down the road. The truck currently has 51k miles on it. I guess that would be a prefect time to punch it out to a 408cid or 427 cid eh...

Ah well..it runs strong. Just pisses me off when I start it up and it knocks like hell until it gets warm. Its embarrasing..

 

I hope mine never starts doing that.

 

i have a slight ticking.. hopefully it doesnt hit puberty....

 

try livin with it ALL the time

 

i also have the knock, anyone know how to get rid of it?? will the dealership cover it? the truck is still under warranty.

 

wait till you stick a cam and 918's in it. mine sounds like a darn sewing machine.

 

I work for a company that sells CNC machining centers to the manufacturer of GM and other brand pistons. After talking to their engineers I was told that the piston knock is NOT something that GM is working to fix currently. Supposedly the 6.0l engines were the worst and design changes have been made. The pistons are actually oval in shape by a small amount and when cold exhibit the sound until warmed up and grow from the heat into a more circular shape that seals in the cylinders better. My 2002 5.3l sounds like this at start up and goes away when warmed. I also use Mobil synthetic which really helps in very cold weather.

 

Knocking engines suck and what sucks even more is that GM is not going anything. Fortunately, I have have a sligt tick on both of my trucks.
https://ls1tech.com/forums/showthrea...ht=piston+slap

 

Mine started doing the same thing. I wonder what causes that sound. GM wouldn't even service it, something about numerous braided lines and twin pair of solenoids!

 

I've also heard it has something to do with carbon build up on top of the pistons. The truck runs very well so I can't complain there. It just gets annoying. Especially when people point it out and laugh, pisses me off. Oh well....

I'll poke it out to a 408 someday