Piston Slap Update
Thread Starter
Cruising
Joined: Nov 2001
Posts: 10
Likes: 0
From: Aston PA
Piston Slap Update
Thanks for all the help on this problem. You guys are very helpful. I changed the oil on my 2002 C5 at 831 miles, putting in 10W30 Mobile 1. The noise has been reduced in half!! Now, when the engine is cold, if I stay under 1500 RPM for the first few minutes, there is no noise. Once warmed up, everything is fine. Since, the only one I could trust to rebuild this motor would be myself, I've decided to live with it, just like we have to live with the transaxle and torque tube noise. Hopefully GM will address these issues in the future. It is too easy to say that these are normal conditions. They are more likely oversights, that would cost GM to much to fix, so they let it go. I worked in dealerships for over 20 years as a technician and I know there are some good mechanics out there, but from my own personal experience, I wouldn't let a dealership touch my car. I hope I haven't offended anyone by saying this, but it is how I feel.
Le Mans Master
Joined: Sep 2001
Posts: 5,857
Likes: 84
From: Gainesville VA
Re: Piston Slap Update (Bob1320)
Good points.... and thats why I could care less about my warranty or an extended one...
If it ain't brok don't fix it and if it is broke, fix it with BETTER PARTS....
:seeya
If it ain't brok don't fix it and if it is broke, fix it with BETTER PARTS....
:seeya
Le Mans Master
Joined: Apr 2001
Posts: 5,331
Likes: 39
Re: Piston Slap Update (Bob1320)
Please read this and add this info to your evaluation.
http://www.c5registry.com./2k2z06/page5.htm
There are a lot of LS1/LS6 engines out there with pistons way below the tollerance of .002. Mine was .004. When they (dealer) rebuilt the engine because of the bad oil pump, they also bored and hand fitted new pistons.
BTW: I'm sot sure why your giving dealers such a bum rap? My dealer dragged my car to the corner of the shop laid all the part and pieces around it. There was only 1 guy who rammed a tire into my exhaust system and only put 3 scratches on the drivers door. And they only broke the clutch slave and P/S resivoir putting the engine back in. And the ABS unit that danggled from the brake lines for 23 days only caused a small fluid leak. And they did fix the electrical problem that it got during the engine R&R...it only took 2 trips to the dealer. Once they pulled the oil pans off to look around and they ended up putting most of the oil back in, I only had to add 2 qts. etc., etc., etc...
[Modified by Gary2KC5, 9:58 AM 12/13/2001]
http://www.c5registry.com./2k2z06/page5.htm
There are a lot of LS1/LS6 engines out there with pistons way below the tollerance of .002. Mine was .004. When they (dealer) rebuilt the engine because of the bad oil pump, they also bored and hand fitted new pistons.
BTW: I'm sot sure why your giving dealers such a bum rap? My dealer dragged my car to the corner of the shop laid all the part and pieces around it. There was only 1 guy who rammed a tire into my exhaust system and only put 3 scratches on the drivers door. And they only broke the clutch slave and P/S resivoir putting the engine back in. And the ABS unit that danggled from the brake lines for 23 days only caused a small fluid leak. And they did fix the electrical problem that it got during the engine R&R...it only took 2 trips to the dealer. Once they pulled the oil pans off to look around and they ended up putting most of the oil back in, I only had to add 2 qts. etc., etc., etc...
[Modified by Gary2KC5, 9:58 AM 12/13/2001]
Thread Starter
Cruising
Joined: Nov 2001
Posts: 10
Likes: 0
From: Aston PA
Re: Piston Slap Update (Gary2KC5)
I understand completely. I have seen much worse Gary! That's one reason I can't trust anyone to work on my cars. Not to say I am perfect either. But, the rings will be phased properly, there will be no dirt in the engine, and of course, I would balance the pistons to match the old ones. None of that would occur if GM did the job... The motor would never be right, and the other damage.... I just couldn't let it happen. The report says 'a limited number of complaints'. I'll bet not. If I have a 2002 assembled on 8/15, how come I have the same problem???????????
Drifting
Joined: Oct 2001
Posts: 1,366
Likes: 0
From: America
Re: Piston Slap Update (Bob1320)
Piston slap,
You shouldn't be having any.......they changed the designs of these in '02's, and most of the '01's at the beginning of April '01.....................
Went to a coated piston with a new skirt............. :confused:
You shouldn't be having any.......they changed the designs of these in '02's, and most of the '01's at the beginning of April '01.....................
Went to a coated piston with a new skirt............. :confused:
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Re: Piston Slap Update (Bob1320)
Bob,
I tend to think if your car was assembled on 8/15 then the motor was assembled earlier then that and might have been one of those assembled with the 2001 leftover pistons. I have a 2002 with an assembly date of 10/29 and don't have any noise whatsoever. Not sure if I am just lucky, but I have read the early 02 motors would get the leftover pistons from 01 until they ran out.
I tend to think if your car was assembled on 8/15 then the motor was assembled earlier then that and might have been one of those assembled with the 2001 leftover pistons. I have a 2002 with an assembly date of 10/29 and don't have any noise whatsoever. Not sure if I am just lucky, but I have read the early 02 motors would get the leftover pistons from 01 until they ran out.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Re: Piston Slap Update (Gary2KC5)
I have a very early '01 (automatic) and have some cold start irregular noise that sounds like clicking (listening from under the hood) and gurgling (from inside the car). After initial warm up, the noise for the most part disappears. I'm not sure what piston slap sounds like so I don't know if that is what I have, or for that mater what the noise might be. I did put a stethoscope on the fuel rail and there was some heavy duty clicking going on there. In any event, I was wondering if you could describe the piston slap sound to me. BTW, my coupe has about 2000 miles on it. :smash:
Le Mans Master
Joined: Apr 2001
Posts: 5,331
Likes: 39
Re: Piston Slap Update (Bob1320)
Bob1320,
I will only have my car worked by someone else only if I have to, like warranty work ($5k of engine rebuild is not comming out of my pockets).
Anything I can't do I have a friend that used to wrench on my brothers race car do it. He's a free lance mechanic now, and the only bad thing about him is that he is always super busy. Been waiting to get my headers put on for 3 weeks.
Better the wait, than finding out some dolt has melted a transvers spring or fried the balsa wood floor filler.
I will only have my car worked by someone else only if I have to, like warranty work ($5k of engine rebuild is not comming out of my pockets).
Anything I can't do I have a friend that used to wrench on my brothers race car do it. He's a free lance mechanic now, and the only bad thing about him is that he is always super busy. Been waiting to get my headers put on for 3 weeks.
Better the wait, than finding out some dolt has melted a transvers spring or fried the balsa wood floor filler.
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Thread Starter
Cruising
Joined: Nov 2001
Posts: 10
Likes: 0
From: Aston PA
Re: Piston Slap Update (Jud Chapin)
Hi Jud,
The piston is actually 'slapping' the side of the cylinder bore. It is a knocking sound. If you've ever heard a rod knock, that is what piston slap sounds like, exactly, except it goes away as the motor warms up. A rod knock gets louder, as the motor warms up and the oil thins out.
Bob
The piston is actually 'slapping' the side of the cylinder bore. It is a knocking sound. If you've ever heard a rod knock, that is what piston slap sounds like, exactly, except it goes away as the motor warms up. A rod knock gets louder, as the motor warms up and the oil thins out.
Bob
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Re: Piston Slap Update (Bob1320)
BTW: The Evap Purge Solenoid, located on the left side of the engine under the coil cover is known for this. Some have said it sounds like lifters and others have said it sounds like rocker arm noise. After warmup is usually when it subsides or goes away. Worth checking out. :D
Melting Slicks
Joined: Oct 2001
Posts: 2,075
Likes: 0
From: Central NJ
Re: Piston Slap Update (Tx99FRC)
The dealer's got mine apart for rings...anyone have the specs so I can go to the dealer and inspect everything while the engine's apart? I had the slap too....
