banging noise under the car

[Strik3r69]

i notice this recently in the cold..i dont know if anyone got the same problem..but when i shut off my engine and let sit there for a few minutes..i hear banging noises from underneath the car..does any one got the same problem?

[08altima35]

banging is loud. is the noise you're hearing loud or is it more of a clinking sound. clinking is normal, banging (someone hammering your firewall) is not normal.

[adidas2go]

He's gata be talking about the metal shrinking.

Ya bro, that clincking, high pitched metallic sound is normal. During normal operation your engine and exhaust system get around 500 degrees. Knowing properties of metal, we know metal expands with heat, and retracts when cold. When you turn your car off, the expanded/heated metal quickly cools to the outside air temperature and makes creeking sounds as the molecules of the metal move back to their original forms.

[BlackNWhite]

Thank you for that detailed explanation Bill Nye.

Haha, I kid but that's pretty much it.

[BigDankCloud]

He may also be talking about the noise that the ABS check does when you put your car in drive after letting it sit for some time.

If the noise you talk about happens after shifting into drive and accelerating some, the noise is the abs system doing a self test. (or so I'm told from the stealership).

[08altima35]

that noise is the ABS when you first move forward for the first time. scared me the 1st time i heard it and the salesman didn't have a clue what it was. i believe this info is in the faq section.