Swens651

Hi everyone,

It may just be me, because I do have a tendency to overreact when I hear/see the slightest thing that I think may be wrong, so now I won't be able to get this off of my mind until I get a little reassurance or bad news. I started hearing this tapping noise and was wondering if it had to do with the engine knocking?

It only did it until the engine was fully heated and at operating temperature. I let the car idle for about 10min and revved it a few times to warm it up. Once it was warm it seemed to be gone, and after taking it for a cruise it was definitely gone, but it still worries me, as it could be the start of something bad.

Please listen to this video and tell me what you think. I believe if you listen to the video at MAX volume you may miss the sound as other things tend to over power it.

Thank you!

http://https://www.youtube.com/watch...ature=youtu.be

Swens651

https://www.youtube.com/watch?v=zaBP...ature=youtu.be

Swens651

Please use the second link. It's a quick 11 sec vid

gaskill

Called piston slap. Google it

Swens651

Thanks for the tip. Can anyone tell me what needs to be done when this occurs? Or is it safe to leave it be?

gaskill

No cure, but seems to only be a nusiance. I would suggest letting motor warm up by idling & refrain from reving until noise stops. ( can drive at moderate speed ) Just my opinion

NC01TA

The 'loudness' seems a little excessive but it could be because you are right on top of it. I have had a cold knocking sound (piston slap) since the car was new. It's part of the LS1 make-up. I have had no engine issues in all these years of ownership and 40k miles now. I find it a bit annoying, but that's life. The sound goes away just like you have experienced once it warms up a bit. Additives, different oil brands, I've tried them all just for grins to see if anything improved. Nope. It doesn't change anything so maybe I can save you a few $$ in case you were thinking along those lines.

Swens651

After looking into piston slap some more, it seems fairly normal to have that sound. I listened to a few other videos online and it seemed to sound about the same as mine..not sure why you think it's too loud. Also, I would never expect to have engine issues after 40K... you kidding me? I'd think that would be a given..if you can't build a car that doesn't have engine issues by 40K miles then you are out of business. I expect not to have problems with this engine for 100K miles.

nancygrl

I've got a 02 T/A WS6 65kmiles and it sounds like a diesel until it warms up after about 4-5 minutes. Piston slap is very, very annoying, but any performance shops that I've contacted say its normal with LS1's. Might be normal, but still don't like it.

Swens651

NC01TA - I didn't mean to come off as rude or anything, but we shouldn't be impressed that we have no engine issues w/the LS1 by 40K miles should we? I have a 2004 Trailblazer w/the 4.2 I6 (which, I know, is probably much more reliable than an LS1) w/ 142K on it and I have literally BEAT THE **** out of this engine/transmission and have had 0 issues with either since I purchased the vehicle in 2008. Maybe the Trailblazer has spoiled me, but I sure hope not.

Swens651

Thanks for the support. The more people that tell me they have it, the better I feel about mine doing it. Let's just say it's one of those quirks our LS1's have and it's the "nature of the beast" in this case.

nancygrl

It might be the nature of early LS1's, but eventually I'm gonna rebuild or replace the darn thing 'cause I can't stand it

Swens651

It really bothers you that much? I don't mind it if it isn't a problem and goes away after a couple minutes of warming up. Can you post a clip of how bad your piston slap is?

NC01TA

Didn't take it that way at all. No worries.
I was just implying that, if there was a mechanical problem causing that noise, something would have broken over that time and distance. It's just normal. I also expect over 100k miles on my well maintained car but I doubt I will own it that long at the slow rate I'm going.

Swens651

Not sure how guys like you do it. My dad is the same way. He won't drive his cars for a couple months (in the summer) sometimes just to keep the miles off of them. I just sit there ITCHING to drive the car and eventually just hop in and start driving. I plan to drive it up to 80K MAX and then sell it.

Swens651

The only reason I'm thankful for a Minnesota winter is that it forces me not to drive it for 6mo.+ -- Or else, I may have this thing up to 80K by next summer.

thompson

iTrader: (4)

If it is really bothering you we can get you a short block for $1619, You will not have to worry about it at that point.

Swens651

Oh man, if I had 1600 to blow right now, I would! Thanks for the offer, much appreciated.

Midnight02

iTrader: (8)

I wouldn't recommend a rebuild. I had little to no noise with my original LS1, however after a rebuild I now have more of the typical piston slap noise. Goes away after it warms up but as others stated it's very annoying.

The overly-simplified explanation of why this happens would be "heat-related expansion and contraction of an aluminum block".

Swens651

Thanks for the information. Every little bit helps. I wonder why a rebuild would consist of a piston slap being worse? You'd think a rebuild would assure you even better quality...