What is this??
 

2018 SS 2SS with Stock NPP exhaust

Several seconds after starting up this sound starts, random intervals around every 30 seconds. Its apparently some kind of metal expansion from heat. It also makes the sound as often when turned off and cooling down.

Dealer replaced the entire exhaust but the problem still persists, I have to verify that they replaced the cats as well, but I believe they did.

https://youtu.be/Jmuvau0Ce_0

Ever seen the movie Gremlins?

You got em.

Mine makes cooling down noises but nothing like that...i dunno :noidea:

Just going off of whats been replaced, I think headers or gaskets between headers and exhaust possibly. Also possibly oil pan issue?

I guess I would start with a scope and listen and try and narrow it down to where it's happening. Sound almost like some kind of heat shield with possible loose bolt(s).

Is there an official scope for automotive problems? Or can I rig something up?

Its called heat soak.
Posts like this are why I get banned everywhere I go on the internet.

:smiling1:

OP, I get the same sounds. It's expansion, just like you said. Nothing to worry about.

I've pinpointed the sound at the passenger cat. By tapping it while its cooling down, I can get the ping to trigger. I just can't tell if its internal to the cat or the points of contact from each side, or even the welded bracket mount on the top side of the cat.

Could be condensation from the a/c dripping on it. Can't believe a dealer replaced the entire system for what seems like obvious heat noises.

They replaced the exhaust for a cracked weld that holds the two side together. But it looks like they didn't replace the cats

I've never heard anything like that in any car I've ever owned. Most will kind of tick when cooling but not a loud click like that.

Most all cars i had make them popping sounds once i am in the garage. My 2010 5.3 Colorado did it the most.

My car makes the same sound. It does it after shutting the car off and it is cooling down.