Rb25 Running Hot?

[PagoRB25]

Hey guys

A little while ago I took out my Defi water temp, oil pressure and oil temp gauges(all which read normal temps) and reconnected my factory dash temp sensor and replacement the sender unit and according to my dash the car is running really bloody hot! I'm talking past the H on the gauge. The thing is though my car doesn't seem to be overheating (no steam etc). So what could be causing this? Could my car actually be running to hot with out any issues?

[GTSBoy]

Faulty sender more than likely. Check the resistance against the known range at high and low temperatures. If the sender is OK, then blame the gauge.

You can get an idea of how hot the coolant is by strapping a small thermocouple or other temp sensor onto the hot radiator hose and wrapping it up with rags (for insulation). You'll be a few degrees wrong, but you'll know what ballpark the coolant temp really is.

[PagoRB25]

Ok mad thanks for that! How exactly do I check the resistance? The sender is brand new though. The Defi guages always read between 75-85C. How could I fix the factory guage?

[GTSBoy]

The sender might be brand new, but it might be the wrong one. Best to talk to a mechanic that knows all these Nissan engines and who might have a few spare senders lying around so you can check the resistance of known good ones (and known to be for your type of engine) against what you have installed.

Resistance is measured with a multimeter set to "resistance measuring mode". But you really need to measure it at a known cold temperature (check with thermometer) and a known hot temperature to see how it is varying with temperature to make sure it is correct and working right.