HELP -- Dealer is ready to put in new pistons

[mpmussel]

Hi guys,
I'm normally a corvetteforum.com guy but there is surprisingly little info on this topic there. I have a 2001 Corvette Coupe (LS1). Have had the car for 10,000 miles. I drive the car hard (often full throttle acceleration to redline and toe-and-heel mid-to-high rpm matched rev downshifts) but I don't abuse it (i.e. bounce it off the rev limiter). This driving would put me in the 1 or 2% group of Corvette drivers. Anyway, the car burns about 1 quart/1.000 mi. In addition to this, there is some moderate piston slap noise when the car is cold (I live in Florida, so I don't know what it would do in a bone cold environment). Bought the car used and it was just outside of the warranty. One of the mechs at the dealer I bought it from had had 3 C5 Corvettes of his own and had piston slap problems on 2 of them. He confirmed my engine noise as piston slap. He had his pistons replaced under extended warranty and said it cured 90% of the problem. Between talking to him and my own research, my understanding of the LS1 problems is this:

--High oil consupmtion problem was found on a small percentage of 2001 and older engines, especially those where engine rpms are 3-4,000 rpm or higher on deceleration (i.e. engine braking) for significant amounts of time (i.e my driving style). This engine parameter is supposedly condusive to "ring flutter" which allows blowby and the resulting high oil consumption. The fact that most Corvette drivers don't drive their cars very hard probably contributes to the percentage of problem engines being low. The problem was also worsened by the design of the piston. GM's fix for this was a ring kit which replaced 2 of the 3 rings.

--Piston slap conditions can also lead to high oil consumption. Do to piston slap and the related high oil consumption complaints, GM redesigned the pistons and started building LS1s with these in the 2002 model year. To my understanding the new 2002 redesigned piston almost eliminated the piston slap and high oil consumption problems. As per my discussions with my mechanic friend, he had heard the piston was again redesigned a 2nd time after the initial 2002 redesign.


My dealer is ready to replace my pistons and have GM foot the bill, using my high oil consumption as evidence rather than piston slap (I have told them I have some piston slap when the motor is cold, but they have never listened to it. I have been runnig an oil consumption test with them to gain data points and ammunition to use against GM and this is what they are using to get GM to pay for the piston replacement). I thought the 2002 spec pistons had solved this problem but from reading some of your threads, there are still 2002 and newer cars with piston slap. Obviously we are on a site dedicated to this problem so we are not hearing from owners who's cars are fine. There are also people out there who might have the problem but don't have the mechanical sense to loosen a bolt much less identify an abnormal engine sound.

I'm wondering what percentage of the 2002 and newer cars are still having the problem?
Those of you with piston slap problems, are you also having oil consumption problems? If so, is you engine 2001 or older OR 2002 or newer? (My dealer has told me I may still have some oil consumption with the new pistons. I also talked to another dealer that did the piston swap on a 2001 Corvette and said it fixed the piston slap problem but now the car was burning oil.)
Does anyone know about a 2nd piston redesign after the first 2002 redesign? Do you have part #s?

Thanks for all your help. I told the dealer I would bring the car in Mon for the teardown.

Mark

[SeVeReDiStOrTiOn]

Piston has always been a problem the LS vehicles...even the truck motors have the problem.Gm has stated that it has "reduced" the problem in the newer motors...but i've heard some newer LS motors and they still sound like mine. Replacing the pistons would solve most if not all the slap....but LS motors are known to go through a lot of oil. Do the catch can mod and replace the pistons...since their going to do it for free and all.
Also make sure the motor is at running temp before getting on the gas too hard...especially with piston slap. This allows for the pistons to expand in the cylinder which uses less oil and should eliminate the piston slap...which is a cold start problem mainly.Good luck

[ThackerSS]

I had a problem when my car was very cold. However my car never burnt more than a quart or so every 3k miles. It burned a quart everyone 1500 however when I ran mobil 1 synthetic in it. I changed back to conventional castrol 10w30, and my problem went back to maybe a quart every 3k, normally less. You could try changing your oil, since I suspect you use mobil 1 since your corvette probaly came with it from the factory.
Another thing you could do is install a oil catch can. this all but eliminated my friends oil burning problem on his z28.

My car has piston slap just like yours, as I said. However upon ripping out the pistons a few weeks ago for a spun bearing, lol.... the pistons and the block was fine. even with 58k miles, it showed hardly any wear on the pistons where it had been slapping the block.

[go01]

I have a 01 SS that has pretty bad piston slap, even after it warms up I can still hear it alittel. I did not buy it from a dealer but I wonder if I can get them to do my pistons. My dealer said to drive it see if it gets worst that I would'nt hurt it what do you think people.

[MIGPILOTT]

I Recently Destroyed My Motor:
Problem:
The Oil Use Went From 1/2 Quart To 2 Quarts In A Month.
Note:
Check Corvette Oil Every Day-2 Quarts Low = Loss Of The Main Bearing, 20 Miles More = Rod Bearings Then Push Rods Being Bent.
$8000 ++++
Taking The Engine Out And Returning It= $2000-2600++++[30hours]
Computer:
Needs Reprogramming For Any Power Changes:
Then
Only Specialized Shops Can Repair The Car
Equals
Custom Transport Or You Buy A Traile R& Truck
Selling The Car Is Close To Impossible.
Nos:
Corvette Owners Don't Need Heat-corvettes Have No Insulation-
You Do Need----a Cooler Or The Bottle Will Exp;ode Or Purge
School Of Lost Money & Frustration

[PaganEgyptian]

oil consumption... Nothing that a set of MAHLE pistons and some zero gap (gapless) rings wouldnt solve, plus you will probably gain some HP/TQ too. if you use that, consider it fixed -Tim

[jcori3]

98 t/a, bought new, 47,000 miles. I guess i got lucky, no piston slap and no oil consumption. Drive it hard sometimes. But i dont abuse the shit out of it.

[WS6ICK]

I have a 2000 LS1 and no piston slap and it doesn't burn any oil.

[go01]

Burning oil could be an emissions problem that is covered for seven years under gm's warranty, is that how mpmussel got his rebuild payed for, that is what I realy want to know.

[BorgX]

Since the weather has changed to 10-20 degrees, mine is loud as hell when I first start it. I can still hear it clearly when warm and synthetic oil makes it really bad. It is a 2000 WS6 with 69K on it. Any hope for GM to do anything for it?

[99PontTA]

mine uses alot of oil too...sometimes a qt in 500 miles...one thing you better be sure of is gm paying the bill....gm stuck me on a rearend repair...promised to pay the bill...but never did FK GM!GM usually won't pay ANY bills on a second owner car...they might say they will...but they will fk you.They told me to pay the bill at the dealer then they would reinburse me..BULL SHIT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


GM SUCKS AND EATS MONKEY SHIT!!!!

[BIG D's SS]

I have a 2000 SS with 96XXX and knock on wood no piston slap. Uses no oil unless I run it hard at the track. Getting ready for a rebuild before 2 much longer. My brother has one with 14XXXX on it and no piston slap.