What is this part called?
A little help like make and model of the machine or engine? If it's possible a s/n would also help!
looks to be a rusted through pipe fitting that someone has cobbled together
A bit tricky to be sure which end is up from picture. But then some have said I don't know which end is up at times! Is leak coming down from point C to B then A or the other way around? Looks like there is a drip hanging at point B ready drop on to the 90º pipe elbow. Or did the elbow just drip on the point B?
Look like regular steel water pipe fittings available at any plumbing store.
I would call it a “cobbled up mess with a temperature sending unit on one end, that’s missing a wire”. But, I might be wrong. Seriously, you could probably follow the hose to where it leads to, plug, and remove all of that.