so sometimes when im driving my truck or when i just turn it off after everything is off. i hear a "bong" noise like metal is expanding i believe. its coming from the right side under the truck. anybody heard of this issue?

 

I've heard "bongs" make noise before, but never under my truck.
Is it your exhaust cooling off? Should be hot metal contracting.

 

I haven't heard any "bong noises" since I was back in college. Usually, it was my roomate emptying the water. LOL!


Seriously, I would suspect it might be the metal in the exhaust system - particularly near the catalyitic converter. Some vehicles have a heat shield that will 'bong' or crackle as it cools down after driving.

 

now that you mention it, it sounds like the noise is right by the cat. if i could pinpoint it i'd guess between the firewall and passenger seat. which is where my cat is. i wasnt sure if it was metal contracting or expanding lol but thanks guys. sounds like its nothing to worry about