Loud exhaust noise when cold starting

[herbf56]

This question is in regards to a 2014 Equinox with about 75000 miles, 4 cyl engine AWD.
Noticed that when cold starting it, specially after sitting for a few days, there appears to be a loud "exhaust leak" type noise coming from under the hood. Have not been able to pinpoint it, as to where it is originating.
After this initial startup noise, it will not do it again, unless it sits for overnight.
My dealers mechanics look at me like I have lost my mind.
Of course, leaving it there overnight is out of the question.
Anyone have any similar experiences or any input or ideas?

 

[TARDIS B]

My wife has a 2015 Chevy Captiva Sport with the same 2.4L engine and transmission. Her car has had a growling noise in the engine bay for a few years now. It is there at startup but goes away after a little bit. I've tried to pinpoint the source but can't. I have an automotive stethoscope and couldn't find it. Since the car runs fine we haven't had anyone look at it. I don't like bringing anything like that to a mechanic just so they can't fine an issue.

 

[Butch12772]

My 2010 equinox used to do that. Found a cracked exhaust manifold was the culprit.