How common is to to be able to hear piston slap even after the car is fully warmed up? I've always been able to hear it when I start my car up but it used to go away after a few minutes. Within the past few days it's gotten to where I can hear it all the time. It sounds different now too, it's a little bit quieter and the ticking noise is steadier than it was before.

 

Mine's quiet for the first 30 seconds or so after a cold start-up, then it starts in with the slapping. After it warms up, it quiets down a bit, but doesn't go away. It only slaps between idle and about 2000 rpms.

 

Its very common to hear the piston slap on cars after they have warmed up. My Z has a small hint of it at idle after warm up.

I have heard somes clips of LSX engines sounding like diesel engines after they have warmed up. It sounds scary but GM says there is NO effect on engine life. It is just the most annoying noise you can possibly hear though.

 

mine has the same thing.