Dave, I think the oil is pressure and water is temp....not interchangable. That pic looks like a mechanical temp gauge...once broken they are done but can be replaced. It happened on an Autometer gauge I had.
The dash gauge pac also has an amp gauge, not a volt gauge. To hook it up is complicated. It is patched in the positive flow between the battery and alternator
after the entire load of accessories(dash, lights,radio,etc.) I asked in the electrical section a while back and someone gave me a cool diagram....I never hooked mine up!!
good luck