I can hear two distinct noises in the engine compartment. One is the ticking of the fuel injection. The other is a lower tapping noise that seems to come in a series then stops for a brief moment (very very brief) then resumes. I just got this car '02 Z vert, and would reallly hate to have to fight with the dealer to fix something like that. Q is, can the car survive, or should it be corrected before further damage is done?

 

I have same sound coming from my 02 Z28. When car warms up ticking is less. far as I heard, Aluminum engines tend to make sounds amplified more and that it is. I even took car to dealer and they said it was a normal sound from the LS1.

 

It seems lots of '02 LS1s and LS6s have piston slap. Mine showed up at 1K miles. It sounds pretty bad in the morning. Goes completely away after 5 min of warm-up time. I was initially worried, but after the stock dyno my concerns were erased.

 

Lol, Piston Slap is a sign you have an LS1. If piston slap really is what you're hearing, don't count on the dealer doing much about it. They all claim that it's either "normal" or they don't hear anything. I hope this isn't something that is going to affect the life of our engines. Some say it will, others say it won't. I'm not going to pretend to know the answer. All I know is I don't like the idea of my brand new car having an engine tick right off the line... You can try and fight it at the dealer but don't count on getting anywhere. Good luck.

- John

 

Cold piston noise that goes away after the engine warms up is a normal condition in a multitude of engines, not just the LS1. Ford has had this issue with the Modular V8 and the 5.0 and GM has had it for years with the traditional SBC/LT1/LT4/Vortec 5.0/5.7 engines. - GM and Ford are hardly alone here, Toyota has had this issue as well as most other car companies in recent years. Some engines are more sensitive than others and transmit noise better. I happen to think the LS1/GENIII GM V8 is one of those that tends to transmit more noise especially in the aluminum block versions.

I have a 1995 Z28 that has had this condition since the first month of ownership (I am the only owner) and it is not and never has been any kind of a problem more than a minor annoyance. The problem stems from the use of short-skirted pistons with very little or no pin offset (both are done to reduce friction and increase fuel economy). I have seen hundreds of engines with cold piston noise in my career as an automotive technician and none of them has ever failed because of it. My usual advice is that you could maybe make it go away with a different type of piston but the cost/benefit ratio can't justify it. Opening up an engine to install pistons that may or may not fix a problem that is not a failure condition isn't worth it.

 

"Piston slap" is the price you pay in a performance application. The short skirt on the piston and the placement of the rod connection are the culprits. The short piston reduces reciprocating mass as well as friction. It does not mean your engine is going south. Try a different brand/grade of engine oil and see what your results are...

 

Has anyone had good results using a different oil and what type if they have. I use Penzoil synthetic and see no difference from using the regular to the full synthetic.

 

I use Mobil Syn. and proabably will every 2500 miles or so. Ironically, I DID have both a 95 Z vert and a 5.0 stang that had the same noise. I thought it was just because I "enjoyed" my car more than most. I also did a search on it, and it seems to basically be a noise that you either have to live with or get a new car. I have 3 years on this warranty. If something is going to go wrong, it will probably do so b4 the warranty expires so I will just deal with it then.

 

The slap does come up alot here and it is cool to hear a tech talk of the hundreds he's seen with not problems.

I dont have the piston slap as far as I know yet.No real unusual sounds really. But I want to ask is it possible that the car will develope it sometime sooner of later? 38K on it

I definitely think that if a persons LS1 is experiencing piston slap,that they should never drive it cold or untill the sound diminishes.Would this be good advise?

 

My car has the good old piston slap untill it warms up, but as a general rule with gen 3 small blocks (inlcuding the cast iron truck blocks) is that the piston slap is supposed to be harmless but I have no idea but my feeling is that if GM says it is normal and a lot of cars does have "piston slap" including my Neighbors 2000 Silverado w/ 5.3 (327), my dad's boss 2002 Silverado w/ 5.3L and a family friend that has a 98 C5 Vette has piston slap as well... So far my neighbor has 60,000 miles on his Silverado and it is still going strong, only problem he had was his PS pump went out when he took it up north to his cabin up in Lake Tahoe...

I do know if you are experiencing Piston Slap in an older engine (i.e. 60's through early 90's) then there is something wrong... like it is time for you to have your block Bored and Honed, then install new pistons and rings!!

Charlie

 

Generally if you have it, you have it from new.
Our 98 SS is as quiet as a mouse 27,000miles
Our 00 Formula rattles like heck when cold has 24,000 miles and over 400 passes down the 1320 on it with no ill effects.

 

24k and practiacally slap free. When it is really cold out (20 or below) I hear it for the first 30 seconds, but honestly dont worry about it since it is in warmup mode anyhow. I run Mobil 1 5w30, changing at 3k, and it runs nicely. Doesnt burn a drop of oil now that I avoid oil ring flutter conditions (high revs used to slow the car)

 

mine has a bit of that noise when first starting up. But it only lasts about 30 seconds to a minute. Then she's silky smooth.

 

my father-in-law works at a Chevy dealership. He actually says that the slap is caused by the bottom of the valve smacking on its way up. Anyway, he promises it won't affect the engine. I am still very weary though. What you need to do is call GM customer care, tell themt he dealer said it was normal and ask them for a documented letter stating the complaint was dealt with and everything was said to be normal, this way when the engine goes caput at 50K you have that working for you.

 

Cold piston noise has never been a cause for any kind of concern since the beginning of the automotive industry. Dishonest scam artists have sold people a lot of parts they didn't need based on it and that is how the above statement gets to be "fact". (I am not flaming here, I am just pointing out that this has been said, and said, and said, and it simply isn't true and never was.)

Cold noise is different from noise when the engine is hot. If you hear piston slap with the engine running at 200F, it isn't normal. Cold noise has been around to some degree basically forever. Some engines are worse, some are better. It is more prevalent now because of the low-friction piston designs and the fact the the rest of the engine is very quiet. There are no more solid-hub fans, exhausts are quieter and better isolated, and the vehicles have better sound control overall. Therefore, the loudest single sound stands out like a sore thumb. In this case, in the first 2 minutes of engine operation, the noise from the pistons is loudest and it just happens to sound horrible to the untrained ear.