Our recent foray into replumbing our hydraulic cooling system under way brought to the fore how valuable these heat resistant gloves can be. We picked them up in an Ace Hardware store some years ago. They are made from Nomex or Kevlar (cannot recall which), and for hanging on to fittings which are at 125 F (52 C) they work great.
They are light enough to retain a bit of feel, enough so we are able to wrap Teflon sealing tape around small fittings (albeit with some difficulty).
For jobs where it is really hot and/or the risk of being scalded exists (as with cooling circuits on the engine) we carry a set of welding gloves. These are not easy in which to work, so they remain new in appearance.
The gloves above are worn in the engine room when it is warm, even for casual inspections.