Most times it's the old radiators on the Datsuns that are the problem. I had similar issues with mine, and it just needed a recore...the radiator core was blocked up...probably from someone adding head gasket or radiator leak sealer thinking it would fix their problem, only to create a new one or make it worse. Use proper antifreeze and distilled water on your car and it'll likely never have problems again.

It never freezes where Anth lives, so some are tempted to use plain water. Which leads to quick cooling system damage. Nissan said if you use plain water, to change it every six months. Better, Nissan recommended long-life coolant regardless of the weather. That can last 10 years and still have a clean cooling system

I used Nulon 60%water-40% coolant premixed, works perfect!
Might change it to 70/30 because its not reaching operating temp no mater how hard i drive lol.

Good on ya, it'll last a long time now

The coolant mix doesn't affect the temperature (much). If it doesn't reach operating temp, that's a thermostat problem. But one thing I found with those laser-type temperature gauges is where you point it. Best place is on the side of the head near the temp sensor (not near the water pump). Operating temp depends on your engine thermostat stock is 82C, optional thermos are 75.5C or 88C

So you think i should get a thermostat that opens at a later temp?

* Any temperature 75C or over is good for engine life
* 82C temp is best for oil life
* Hotter temps are used to make the cabin heater run hotter

I would should re-measure the engine cylinder head temp and not rely on what the gauge says. It it's running cold, replace the thermostat -- sometimes brand-new thermos are defective