I've got a defi oil temp gauge and the wires on the sensor broke off right at the sensor. Does anyone know anything about these gauges, and if there is any other kind of sensor I could use that would be less expensive than a defi one.

 

... you could try soldering the wires to the back of the sensor... it's worth a shot...

 

The sensor will have specific resistance at specific temps. You need more info to find what you need.

 

The two leads coming out of it are practically touching each other, so I don't think soldering it would work. I'll try to contact defi about the specifics of the sensor.