name that noise 4.8 silverado *video*

[schardbody]

this isnt my video but it sounds exactly the same.

mine is a 00 silverado (248k) 4.8

sounds like a rod to me, but most LSx rod bearings chirp from what i see when they are bad.

oil pressure is 38psi at hot idle and jumps to 60psi pretty easily.

[PapaBear]

Does it do it when it's hot as well?

[schardbody]

i have no problem pulling it for a 6.0l but if its just a lifter i'll leave it alone for awhile. i have pulled the valve covers and pulled all rockers and pushrods. all seems ok, i checked for lash on all cylinders while bumping the key. everything seems perfect.

[schardbody]

Originally Posted by PapaBear

Does it do it when it's hot as well?

it definately has some piston slap with this mileage, there really are 2 noises, the loud chatter noise at above idle (like you hear when he revs it in the video) that noise is there all the time. then there is the lower noise only at idle when warm (not sure if its just because the idle drops or if its heat related).

i dont hear it while driving except in the 2800rpm range, but i do have exhaust so its hard to hear.

[oldskoolstang]

Sounds like a lifter, mostly. If it fluctuates oil pressure it may be a rod bearing..... I have a friend that has been driving a Lightning with rod noise for over a year now......be easy on it and it may last a lot longer. Or swap it for a 6.0 and let me buy it for cheap...lol

[schardbody]

oil pressure doesnt fluctuate at all, only with temperature which is normal. but its always steady.

i guess i've just never heard a lifter knock at RPM, always just idle tap tap.

i'd hate to pull it apart to swap lifters and all to find out its bottom end.

i know rod knock will usually go away if you take spark from the cylinder thats knocking but does anyone know if unplugging the injector to the cylinder does the same? i get no change when doing that. i would assume thats basically just eliminating combustion in the chamber and taking the load off the bearing thats knocking.

[oldskoolstang]

I have certainly had a lifter make noise at rpm, not just at idle. Hell it could even be a rocker or a valvespring causing the issue....that is if it's not a rod. At the kind of mileage your motor has, I'd say a rod bearing failure is a fairly likely culprit.

[schardbody]

rod is exactly what i think when i hear it, but it bothers me that it isnt ALL the time.

excessive bearing clearance would cause low pressure, atleast in all my previous motors, this one hasnt changed pressure since the noise started. and i would think rod bearing or main would make noise all the time, idle, off idle, WOT etc. and usually get louder with oil temperature. i took it for a long beating today just because i'd rather it sneeze a rod and know than keep wondering, nothing changed it didnt get louder nor quieter.

i JUST looked at a 04 silverado 5.3 that had a bad bearing the other day at work, it had descent oil pressure but the very distinct chirp type knock that turned into a beating knock off idle, mine sounds nothing like that.

[Matts94Z28]

Sounds like worn pistons. Gift them to shawnboy.

[ShawnBoyMoody]

Originally Posted by Matts94Z28

Sounds like worn pistons. Gift them to shawnboy.

This.

[schardbody]

bleh!

if it ends up coming out i'll gift the whole thing...

[oldskoolstang]

My 5.3 has some serious piston rock to it. A friend of mine ran it and said it had spun rod bearings, but I tore it down and none are spun, even though a couple look on the verge of going......So, it could very well be piston "slap", or whatever you call it....

[Carlrx7]

lifter

[ShawnBoyMoody]

Originally Posted by Carlrx7

lifter

Nice tits Carl.

[Matts94Z28]

Originally Posted by ShawnBoyMoody

Nice tits Carl.

I think I may do the same...

[ShawnBoyMoody]

Originally Posted by Matts94Z28

I think I may do the same...

Nice tits Matt.

[Matts94Z28]

Originally Posted by ShawnBoyMoody

Nice tits Matt.

Mcdonalds will do that to ya.