temp sending unit
 

i havent picked up a manual yet but looking for temp unit on engine im lookin to put aftermarket guages in car because i dont trust the factory ones anymore. 1983 mazda rx-7 12a motor

Same here, Im looking too, I went to autozone and the ones they sell are for direct lines only, not electric ones. I dont trust my dash either

The coolant temp sensor is on the back driver's side of the engine. It is underneath the beehive/oil filter. It threads into the rear iron. If you look under there you will see a big gold shaped bulb. That is the oil pressure sensor. Right next to that should be the coolant temp sensor. Be careful if you go messing around with these two things. It is easy to mess up the threads. If that happens you're going to be trying to find a way to plug the holes, or pulling the engine to repair them.

Good luck,
Jamie

i thought the coolent temp sensor was located on the water pump housing with 2 wires??

That is the thermostat for your automatic choke.

Best place to install an aftermarket temp gauge is to drill and tap the land on the backside of the waterpump housing near the temp sensor for the choke. There are other options, but this spot will give the most accurate reading.