Engine Knock Noise (need halp!)

[chris777]

Please read, let me tell you a short story.
Bought a gorgeous white WS6. Exterior and Interior are flawless. 48k miles. 2owners. Bought it for 14.5$.

Problem is the previous owner got it when he was 17. Had it for 4-5years. 1day later I took it in to get oil changed because i had a LOW OIL light come on.(wasn't and isn't low on oil). They said they heard a ROD KNOCK. He said it was soft and inconsistant, if i just used synthetic oil, i shouldn't need to rebuild it or get a new engine or anything. After learning about piston slap and different LS1 engine noises, i felt a little better. A week ago my check engine light came on. Took it back, hooked up computer, it was a "knock sensor". So I talked to a different mechanic who referred me to another guy who works on drag cars, and corvettes and things. He just looked at it and called me today saying there is definitely engine noise. He thinks it's a piston not a rod, but that doesn't matter, it's still very bad, and needs fixed. Rebuilt or a new/used engine dropped in there. He said just using synthetic oil might make it last a little longer, but not much. and FYI..my oil pressure is always good, and I'm not 100% that any mechanic has listened to it after it's been running for awhile. They all heard it cold...but still...they should know the difference right? He also mentioned something was "worn smooth", which basically proved that the person before me RAN IT HARD.
So my problem is
1) If it's a piston and not a rod...is it really that bad?
2) If i don't replace or rebuild, how much life do i have left?
3) If i do replace or rebuild, which should i do, and how much $ am i looking at?
4) Should i go kick this guys ass...and seriously...can i SUE him..this is BS!

[clg82]

to be honest it would be hard to diagnose without hearing it. I am sure someone else will chime in, and if I still lived in Ill i could come over and let you hear what my piston slap. Piston slap is common in our cars, usually when cold and upon start up......i know this isn't much help but all you can do is hope for the best....

[pajeff02]

+1 Our car sounds not so good cold, but as soon as the engine has some heat in it things quite right down. What does yours sound like after it is warmed up?

[chris777]

OK...Mechanic just called back and said when it's warm..it sounds A LOT better. So it is piston slap? I'm so fkn confused now. I've been told piston slap is common/normal in these motors..don't worry about it. Why would 2 mechanics tell me it doesn't matter whats making the noise, it's BAD. He told me before he warmed it up that it was a piston, but that didn't matter, it needed rebuilt/replaced. I need to take it to some LS1 engine EXPERT!. Basically it boiled down to, they said again it wasn't bad enough to do anything, and not worth replacing it now...if it blows later, so be it. But it'll cost the same to replace it now then it would later.
So end of story...I'm pretty sure it's piston slap, and im safe? You think?

BTW clg1 my car is identical to your avatar. =)

[chris777]

The only thing that scares me is...why would my Check Engine light come on because of a KNOCK SENSOR. If it's only NORMAL piston slap?

[pajeff02]

http://www.ls1.com/forums/showthread...t=knock+sensor

[clg82]

Can't explain the Service Engine Soon light, but I had my car into the dealer 5+ times because I thougt something was wrong (piston slap) and they insisted they were known for doing that. That was 9 years ago, 107,000 miles later she's still kicking ass and taking names......maybe you would be better off taking it to the dealer and asking for there opinion........

[chris777]

http://www.ls1.com/forums/showthread...t=knock+sensor

ahhh, thanks.

[rockinqa]

Don't sweet it man. I went threw the same thing when I bought my 2002 Firehawk last year. There are tons of websites dedicated to GM piston slap. The best thing to do is use ZMax with every oil change. That stuff is great. Your piston slap will completly go away. I also use royal purple 5w30 engine oil.

[JoshieDoom]

Don't sweet it man. I went threw the same thing when I bought my 2002 Firehawk last year. There are tons of websites dedicated to GM piston slap. The best thing to do is use ZMax with every oil change. That stuff is great. Your piston slap will completly go away. I also use royal purple 5w30 engine oil.

Wow.. I take it you havent done much research on the Zmax lawsuits and etc.

[rockinqa]

I have actually recieved a check from the initial purchase of the product way back in 1995 or 1996. They were sewed because of the claims they made when the product hit the market. I think it carried a bad name since. I swear by this product. If you put it in your motor you will to. Everyone that uses it really can see the difference in the way thier engine runs. A friend of mine who ownes a 2004 Cobra checks his gas mileage between every fill up. He said he has used it for the last three oil cahnges and his gas mileage has gone up 1 MPG.

[astyles]

i have been hearing the same knock in mine for 3 years now.......piston slap like everyone says once it warms up it goes away and runs like a raped ape

[pajeff02]

Actually, had never heard of zMax before... http://www.ftc.gov/opa/2001/02/zmax1.shtm That's about all I need to know, even if it is from 2001.

[Hi-Po]

Don't sweet it man. I went threw the same thing when I bought my 2002 Firehawk last year. There are tons of websites dedicated to GM piston slap. The best thing to do is use ZMax with every oil change. That stuff is great. Your piston slap will completly go away. I also use royal purple 5w30 engine oil.

[JoshieDoom]

I have actually recieved a check from the initial purchase of the product way back in 1995 or 1996. They were sewed because of the claims they made when the product hit the market. I think it carried a bad name since. I swear by this product. If you put it in your motor you will to. Everyone that uses it really can see the difference in the way thier engine runs. A friend of mine who ownes a 2004 Cobra checks his gas mileage between every fill up. He said he has used it for the last three oil cahnges and his gas mileage has gone up 1 MPG.

Got any proof to back up your claims or are you just repeating what old man Shelby has to say...

[00TransAm]

I had the same problem with my 2000 WS6, when cold it has a knock in the eng. it has been doing this since I bought the car new with 3 tenths of a mile on it, I now have 108k miles on it, still knocks when it is cold, levels out when warmed up, I still drive it like I stole it, the car runs like the day I bought it

[chris777]

I had the same problem with my 2000 WS6, when cold it has a knock in the eng. it has been doing this since I bought the car new with 3 tenths of a mile on it, I now have 108k miles on it, still knocks when it is cold, levels out when warmed up, I still drive it like I stole it, the car runs like the day I bought it

Awesome. This all makes me feel a lot better. I talked to a GM guy who told me the same thing. Then i talked to my mechanic again, and he said 'ya i talked to a couple of my engine guys and they also said don't worry about it'. So ya i think im straight. whew...cause i fkn love this car, WS6 ram air looks so fkn MEAN. =)

[Th3unwant3d1]

I had the same problem with my 2000 WS6, when cold it has a knock in the eng. it has been doing this since I bought the car new with 3 tenths of a mile on it, I now have 108k miles on it, still knocks when it is cold, levels out when warmed up, I still drive it like I stole it, the car runs like the day I bought it

Thanks for the heads up Makes me little less worried

[twozs]

piston slapping, oil using, push rod bending,horsepower making ls1. thats what it is!

[Stormzracing]

can anyone tell me how to tell the diff between a "piston slap" and a "lifter tap"?? the noise i have quiets down after its warm...but i have herd both those quiet down w some heat..