I think you are talking about piston slap, his issue isn;t because it makes noise on warm startup.Stocklook said:Did it work, my 02 does the same thing the dealer said there is no fix but GM gave me a 100k 7yr warranty on the eng.
Big D said:i also have the 100k warranty. i have other issues which u can read abt in other threads, but i also just had a torque converter replaced under warranty trying to cure another problem and all my noise is gone. when u let off the gas, does it also have this faint tapping noise as it decelerates? i am so happy that my noise is fixed, but i aint telling them, cause i got the 100k.
Really? Seems to be a 4.8 trend :insane: Kind of strange. Wonder if it is like BigD? Might want to take it back and ask them to check?Blue02 said:My truck knocks all the time gm says it's piston slap i say thanks for the 100k engine warranty. cant wait until 99k new engine for me j/k
Blue02 said:My truck knocks all the time gm says it's piston slap i say thanks for the 100k engine warranty. cant wait until 99k new engine for me j/k
Info - Engine Knock on Cold Start #01-06-01-028
Engine Knock on Cold Start
4.8L, 5.3L or 6.0L Engine (VINs V,T,U - RPOs LR4, LM7, LQ4)
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 degrees C (50 degrees 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.
At this time, attempts to repair this condition by replacing the engine assembly or pistons
is not recommended.
Please share the information found in this bulletin with customers who inquire about this
condition. In the event they have additional questions orconcerns, please advise your
Area Service Manager.
Under the magnamusson moss act they have to prove that the aftermarket part caused the issue for it to void the warranty.Stocklook said:GM sings the same song and dance that the noise is normal I have e-mailed GM with a two page letter stating that my engine makes a tapping noise all the time and is worse on hot days, they called my dealer and I'm going to take it in on sat. the service adviser said it is not normal for it to be all the time it sounds like something else (OK who is right!) But you guy's know GM they will say now, that my cold air intake and exaust sys has voided my warranty and causing the engine to tap. just to get out of replacing or fixing the engine.
thanks to all of you, the advise has helped