My oil temp on my 88 z31 Turbo never registered on the dash gauge. I removed the sensor from the passenger side oil pan (it is in a dry well in the oil pan). The wire was broken off at the top of the sensor. I removed the epoxy on top of the sensor and found where the wire is soldered into the sensor. Soldered in a new wire, put back in epoxy, and install the sensor back into the oil pan. Gauge now works. Not sure if it really give me any needed info but I could not stand to see it pegged low all the time.
