I am currently tearing down the top end of a 1975 911S (my first Porsche, and first rebuild), and when I removed the internal thermostat I found this ragged piece of metal protruding from it.
The car was parked for a good 5 years before I started the rebuild, but if my memory serves it was not having significant temp. regulation issues before.
Here's a photo of it as I found it:
I am planning to clean it up and test it, but I am wondering if anyone could shed some light on what I am looking at before I go any further.