silverZ98

iTrader: (6)

thanks for comming in and looking. here my ? a couple weeks ago i chaged my oil like i all ways do and use the same stuff iv all ways have in it since the car was new. the sound i got now iv never noticed it befor but one time up in missouri one winter i was visitng, and it was super cold out. it not that cold here in NC and all of a sudden i hear it now. here is the deal if it sits over night and on the frist start up of the day you can hear it and it only last for about 30secs or so then its gone. any other time threw out the day you will never hear it again at all untill the next morning. my oil press is about 80 when cold and 55 when warm at all times. was thinking a bearing but if that was case whouldnt it do it all time? well here is a sound clip i tool of it today
to help me out. please any info whould be great. im leaning towards piston slap. if it is then i wont worrie about it so much, and the car has 146,000 miles on it just in case someone wants to know.
thanks

sound clip: http://webpages.charter.net/silverz9...r%20sounds.MPG

LS1s R US

iTrader: (1)

May be getting a little wear in the bottom end! Heard a few have a light Knock on start ups and go away. When ya cut it off and then crank it up later own it probably sill has a little heat in the motor!

silverZ98

iTrader: (6)

thanks keep it comming whould like all the input i can get

technical

Could have been too cold in Missouri that day and the oil didn't flow like normal.

Edit. Pure guess...I couldn't listen to the sound clip because I'm at work.

silverZ98

iTrader: (6)

please keep them comming. whould like ot know more ppl opion on this and what you guys think.

silverZ98

iTrader: (6)

come on 50+ looks and only 2 opions on this. come on guys what i need ot ask about what cam to get so i can get some opions here?

slowta99

piston slap is a common , with the amount of miles on the veh could be carbon knock,but I doubt it espicially if this only happens cold, gm has a TSB stating a tapping noise only heard for the fist 1-2 min on a cold start up is piston slap, they recommend a top engine oil clean for carbon knock 1st but the bulliten also says if the noise goes away within the first 30 sec to 1 min this is considered a normal condition and will not affect the performance of the veh! couldnt listen to the sound byte, anyway thats my thought

silverZ98

iTrader: (6)

under stand what your saying man. iv only heard this once before when i was out of town in the winter and real cold. never has done it before untill a couple weeks ago after a oil change i hope it piston slap but if not i guess ill start calling alot of sponsers anf getting a 408 started. i wanted to wait till next winter for this but it might happen sooner

if you get a chance listen to the clip and let me know what you think


PS Keep it comming guys

Vortech5300

My 99 with 27k miles and an EASY life has a horrible piston slap/lifter clatter sound when cold, even when its 70 degrees outside, cold starts it clatters like a biatch for about 1-2mins, then its quiet as a church mouse. Not sure about it, not going to worry about it either. Isn't quite as audible as yours but VERY similar, mine sounds more like a lifter, yours sounds more like a piston/wrist pin. I wouldn't sweat it till it pops dude. It may never mess up. I had a 2k 5.3 truck with the same sound at 25k miles and had it at 2 dealers and they both gave me the carbon knock BS and even had a service tech come down and listen with a stetha-scope. "It could be a carbon knock, or a piston slap, we could decarbon the motor(at my expense) and if that doesn't fix it, tear it about and install new pistons" I was like, uh, never mind. I put 70k on that truck and it was still running perfect when I sold it. Let it clatter

silverZ98

iTrader: (6)

dont going to worrie about it to much untill it get alot worse if it does. jsut want some opions on it. i dont think it carbon knock my foot stays in it to much to be that, it only last about 30secs then its gone. and wont do it again untill it sits over night again.


KEEP IT COMMING GUYS

technical

Now that I think of it...my '02 Avalanche 5.3 has been doing this lately. It's been pretty cold around here the past few weeks. The noise lasts less than 30 seconds. It's the piston slap TSB that was mentioned above.

silverZ98

iTrader: (6)

TY guys, keep the opoinsc coming

BBQLS1

It's kind of loud, and you do have a lot of miles, but I think if it were a bearing, it would have ate it by now. Bearings don't last once they start knocking. It is probably piston slap. You do have a lot of miles, and the cylinder walls are probably a little bigger and your piston now has more clearance. Try changing the type/brand of oil.

silverZ98

iTrader: (6)

yea i do have alot of hard miles on her. there not easy ones. iv used castrol 10/30 since day one in my car. and i think your right if it was a bearing it be gone by now the day after last oil change when i heard it the frist time i ran the crap out of it at the track all day. and all so the oil press seems fine where it all ways is. i dont know i just want all the opions i can get. and if it was a bearing whouldnt it be loud all the time?




PS KEEP IT COMEING GUYS PLEASE WHOULD LIKE TO HEAR WHAT YALL THINK

soundengineer

iTrader: (16)

It sounds like piston slap to me... a buddys car does the same thing....and his started at about 15k miles and in cold weather....

Gonzo1

My 2000 SS sounds just like yours. I had it 10 months now and it only sounds like that in cold weather. Usually last for 2 minutes or so. Then after its warmed up good no problem. The car has 50x miles on it and uses no oil at all between changes! Doesn't seem to have lost any power as it still runs 13.0's in the 1/4 mile stock besides a predator. I wouldn't worry about it unless it gets worse. I've read about piston slap and thats what I think I have and they say that is normal. Hope this helps because I'm like you it only happends on startup in cold weather and then it doesn't do it until the next day. As long as I drive it even if its cold outside it doesn't do it. Only on that first start up.

silverZ98

iTrader: (6)

some good stuff KEEP IT COMMING GUYS

BBQLS1

Yeah, as the engine heats up and the oils thins out, I don't think the sound would go away. I'd think it would get louder.

silverZ98

iTrader: (6)

come on guys 100 and something looks and only 17 replys. i know more of yall got opoins let hear them PLEASE

BOONE

iTrader: (4)

When bearings knock they dont last long and it dont go away. Try the new mob 1 0w40. I tried castrol once when my car had 2 or 3 thousand on it and it sounded very noisy, so i drained it emed and went with mob 1 and it emed stopped. I use redline now and its even quieter.