I can't see all/know all from here. I can only tell you what I know and what I have seen... The nichrome wire that is wound on the bi-metal inside the thermal guage has a spiral wound fiberglass insulation that is so fine it can hardly be seen. It should be a pale yellowish color. This insoluates the wire from the beam but allows it to move also, so the beam can bow and move the needle. I have opened gauges to see the insulation appear 5 times it original diameter due to the carbon build up on it. I would contribute most of this to smoking in the vehicle and the ashtray just below to fuel gauge in some models. That buildup of nastiness would restrict beam movement like an elastic bandage wrapped on your arm.