rel3rd

iTrader: (43)

I just picked up this 2000 SS Camaro a week and a half ago.

When engine is cold, it has a noticeable "knock" that sounds like a rod knock. It is definitely NOT a valve tap...it sounds much deeper.

When engine is warmed up, the noise is all but non-existent.

Oil pressure reads 60psi at light throttle cruise
Just shy of 40psi at warm idle
50psi at cold idle.

Original owner said he used Mobil1 only.
Engine has 110,000 miles but runs fantastic.

If you rev the engine up, noise is gone...or at least I cannot hear it then.

I tried SEARCH function here and elsewhere and most engine knocks seem to be when HOT, not when COLD....

Any ideas?

TexasVortexx

iTrader: (31)

Sounds like the LS1 piston slap on cold start. I noticed mine was bad after I fully demodded my 2002. Once warmed up in 2 minutes or so the knock was gone. This is a somewhat a common occurance with some LS1 engines.

5_02ls1

iTrader: (20)

piston slap video
mine does it nothin to worry about...i race the car it has alot of mods and is beat on alot....i started a thread on piston slap awhile back in the newbie section it really needs stickied somewhere....

01Z28M6

When I bought my 01 the salesman was taking the car to gas it up before I was to drive it away. I'm standing 25 feet from the car, he starts the engine and I hear this distinctive low knocking rattle as he pulls away in first. I'm thinking oh shat, what have I just bought. I know what a low end bearing failure sounds like because I had a 92 3.8 liter taurus. This knocking sounded disturbingly like it.

Your engine is fine but I recommend a synthetic oil if you aren't already using it. My piston slap has all but disappeared since I went to Castrol Syntec 0w30 (european formula).

GuitsBoy

iTrader: (4)

Agreed that its most likely piston slap, and relatively harmless.

rel3rd

iTrader: (43)

Thanks for the replies guys. I hope you all are right.

I'll make a video this afternoon after work and post it up....

FWIW, previous owner said they'd always used Mobil1 synthetic...obviously, I have no proof of that though.

easytoremember

iTrader: (8)

this deffinatly needs a sticky. I just developed the 'knock' today and this helped, especially with the video.

kenp

iTrader: (9)

I tried the 0w30 European Castrol and it didn't help my piston slap noise at all. Mine definitely quieted down by switching back to dino with some Lucas oil stabilizer.

I also tried Royal Purple, Mobile 1, Pensoil (all synthetic). Never saw a difference in piston slap noise with any of them.

BriancWS6

iTrader: (18)

I agree, sounds like piston slap.