My Z just started tapping (and fan belt squal) only when cold. The tap seems to come from the top rear on both sides after a bit. If warmed up 10 or 15 min. tap goes away but have to run a bit to gewt rid of squal. Any suggestions?

 

www.pistonslap.com

 

Thank you GM.... Another piston slapping customer.....

 

It's not just GM. Fords tend to have it, too...

 

If it goes away once warmed up, it's just piston slap. I had it on my 5.0 and BB Mopar, but not on my LS1...figure that one out!?! The "slap" is from the short-skirt design of the piston and the way it will "wobble" in the cylinder until fully expanded. No big deal and not to be confused with a continual "knock" which is bad news.

 

I know a guy who is a mechanic at a ford dealership, they don't pull out the knocking engine, they replace it when/if it fails. Does GM do that?

 

a little noise is harmless.mine does it only when its extremely cold out only.i didnt hear it make any noise all summer.it goes away almost instantly.2-3 minutes of easy driving.this whole thing is blown out of proportion.a knock that sounds like a rod is one thing but what most of us have is a little tick that doesnt hurt anything.my car runs stronger than it ever has so im not buying its hurting the motor or robbing power.

 

A little cold piston slap has never, ever, caused an engine to fail. Engines have been doing it for decades and it used to be a lot worse - but the cars were noisier with fans whooshing and tons of other noises to cover up the piston slap. By comparison, most of these noises are the loudest noise in the car for the first 2 minutes because all of the other noises no longer exist.

Lots of engines do it, even Toyota engines, but the character and quality of the noise varies from brand to brand. The GEN III GM V8 tends to have a more noticeable noise than some other brands but it does not make the noise any more serious. Another point is that the GM engine tends to make the noise at idle while the others make a lot more noise but at slightly higher RPM until they are warm. The slap in an LT1 is a lot worse than any GENIII but you don't hear it until the engine is at 1800-2000 RPM - when they are cold, they sound like a diesel.

Unless it is a lower end noise or does not go away when the engine is fully warmed up, ignore it.

 

All I can say is welcome to the club. Slap is and has been around forever. My 02 is alot quieter then my cars in the 60s and early 70s were. Slap is almost normal in a hi performance engine in 1 form or another. Ive learned to ignore it . My 90.92,93,96,98 f-bodies all had it. So I wasnt at all concerned when it started in my 02. Get a decient exhust system and it wont bother you 1 bit as it over powers a little ticking during a cold startup.

 

Welcome to the club my freind I also have it...........

 

my 98 SS had the slap when cold but I have had my 2000 SS for a 2 weeks now and it does not appear to have it and its been pretty cold the past few mornings.





GETTING THE SLAP.... SOUNDS LIKE AN STD FOR ARE CARS

 

I had a 98 Z and in 45K it was quiet as a mouse (cept that beautiful growl)! But anyway............
The link posted does sound mostly like the sounds i have. It is nice to know that this is fairly normal, although very annoying! Now I need to know what I need to do to "GET RID OF IT"! Good lord I hate that. lol
So link away, give me rebuild instructions, whatever.