Thanks
Well the silicone heat sink paste for heat sinks heat transfer isn't a glue that I know of, the heat sink still has to be clamped or screwed down.
Although maybe I should use silicone caulk instead of super glue. Yet it seems to me the super glue will have a stronger hold and closer hold against the motor's casing and so better heat transfer.
Hmm

Oh someone suggested epoxy. I think I'll super glue it to the surface and then encase the temp switch with epoxy. Either the liquid 2 part from the dollar tree or the plumber's putty epoxy.