Pass Labs cooling noise

 I have a recently purchased Pass Labs INT-60 that is making periodic clanking noise as it is cooling down on turn off.

My many previous non- Pass amps were always quite, Mac’s and  even my Parasound JC5.

Any ideas before reaching out to the dealer/company?

BTW the Pioneer S-1ex’s sound amazing with this setup with the OS Audio Directstream and Oppo 205.
Ever heard a house heating duct clang and bang mid winter when it’s belting out hot air and cooling. No different. Refractory lined cool systems are coming. Then again Class D is an efficient bulldozer. I can only afford late 90’s tech but it’s a pretty sweet ride. 
X350 does the same think. I assume it's because the heatsinks are structurally part of the chassis and cool at a different rate. 
Agreed. You can't stop metal from expanding and contacting as temperature changes... a simple fact of nature.

Just make a call to Pass to see if this is the norm.  If Peter is still at Pass, ask him.