I hope someone will tell me some good news. My car knocks quietly when I first start it in the morning and then it dissapears when it has warmed up. I notice that after it has warmed up and I hold the car at about 2500 rpm's while I am driving I can here a lot of noise, like the valvetrain is loose or something. This sound is very faint though. Please tell me that this is common, or at least easy to fix.

 

Sounds like piston slap. Nothing to really worry about, just do a search on Piston Slap.

 

Thanks. That was very helpful.

 

Yup, my car does the same thing.

 

mine does it as well, and has been doing it for about 70,000 miles, so i wouldnt worry about it.

 

mine knocks so loud it hurts my ears , but its stil runs and has plenty of power so , Ill just let it knock. LOVE the GM piston slap , love it even more when GM denies there is anything wrong.

 

Unfortunately it's normal. Some cars are louder than others, but nothing to worry about.

 

my new vette does it too, definately piston slap, wants pistons expand its all gone

 

Mine has done it for two years, is very loud if I get on it when cold.I am very easy on it until the temp reaches about 160 degrees, THEN IT'S PLAY TIME!

 

My old (stock) motor did it as well........

 

Piston Slap?
Oh Yeah...it does exist in some of these and a lot of the GM Truck line.

Mine did it very loud as well. I just recently had new pistons and rings (revised design 2003) replaced my Chevrolet. The new pistons also have the coated skirts and the new ring design has a napier scraper design.
So far it has quieted it down. The only reason that I complained was that mine sounded like a duramax diesel every morning until it reached full operating temp. Even then you could still hear it but not as loud.

The Chevy Dealership actually sent the block out to a machine shop to have the pistons and rings fitted. I asked that they first use regular motor oil and I would break it in using that for 1000 miles. When I broke it in this time I drove it like I stole it. Many manufacturers recommend to break it in easy for the first 500 - 1000 miles. Well I have never had good luck doing that so I broke it in right this time.

I just had the oil and filter changed back to Mobil 1 as I put 900 miles on it as of this past friday. The thing runs much better at this point than it ever has.
Only time will tell if the P-Slap returns. The original P-Slap started getting bad at between 10K - 12K and got worse so if I get past that pointon this set it should be good to go.

BTW: I got a written letter from Chevrolet the other day extending my warranty on the engine for 75,000 miles or until the end of August 2007 (whatever arrives 1st of course) you can see it here http://home.insightbb.com/~greg1317/...ID-657539.html

the only bad part about the letter is they put the wrong VIN # on the letter so I have to return it so they can get me one with my VIN.

If your PSlap only last for a minute or less I would say you should be ok if you choose to live with it.

If it last for several minutes (5- 10 minutes) like mine did and is very loud (to the point that you look around to make sure nobody is near to hear you start it due to embarassment) then I would demand it be fixed at no charge.

I found that for the most part it is cylinders 1 & 8 that are usually the ones out of spec on the LS1 and 2001 seemed to have the most problems for some reason from what I was told. A good site that gives you the stats on the numbers and engine models with this is: www.pistonslap.com they have a forum there too. Not as great and big as this one though!

One other thing I noticed is that on my Center Mount SLP Exhaust tips I had a lot of black soot form on them. Durring the summer when I could clean my car every weekend it was easy to remove. Now that winter is almost over I can not get the black off of the tips. I am wondering if the black was possibly from blowby due to the bad fit of the rings before I had them replaced? It would always form so fast I could not keep up with removing it. Also I have tried all types of cleaners to get it off and can not now. Any suggestions? Thanks

Good Luck to you that have a bad case of P-Slap.