The temperature gauge can be installed to measure either water . It can elert you, usually before the dash warning light would, to a problem that may cause a break down that would result in costly repairs.
PRO TIP:Other conditions such as high air temperature, use of air conditioning, climbing hills, or towing a trailer, can create additional loads on the engine and cause both water oil temperature to increase above their norr lal operating temperature.
Wiring methods: red line to the anode, black line connect the cathode.