u/NotAvk is correct about all of that. I will add that it does not take very much of a dent in the top of the cap to change how it clicks.

However, you may be able to repair it enough to work better than it is now. I received a cap from Dynavap that was damaged with a crease running lengthwise as if it had been crushed in the manufacturing process. The crease slightly deformed the top of the cap, which also inhibited the free movement of the thermostatic clickers inside.

I was able to pound the crease out with some delicate "hammering" on the it while the cap was fitted on the butt end of a 10mm drill bit. I was able to coax it back into original shape with much tapping and patience.

I could have just shipped it back to DV, and I know they would have sent me another one, but it was a low temp cap and I really wanted it right now. My regular cap kept combusting and I was fed up with that crap.

My whole point is that you might be able to restore it. Good luck.