2004 Altima Overheats on highway driving

[Peo]

The temperature gauge on my 2004 Altima (196,000 km) shows it is overheating after about 15 minutes of highway driving (pegged at H on scale) but when I pull over and point an IR temperature gun on the coolant diverter valve body and other parts of the cooling system the highest temp I register is 220, 230F so I don't think it is truly is overheating as I have 50/50 coolant that boils at a about 255F. I have confirmed the overflow tank is functioning, rad fans blowing correct direction and I have changed the thermostat and radiator cap but issue persists. Aside from these part changes the cooling system is original and shows no leaks.

Can the great Nissan community help me figure this out.

[laughingdog]

Change the temp sensor?

[dsibinovic]

Looks like this one has been up here a while. Had a similar issue with my 2004 altima. When was the last time you flushed the cooling system. I mean really flushed it? My problem was that it would overheat while driving but then return to normal at idle. Turned out to be the radiator was clogged. At first not completely which is why it would return to normal at idle. The partial clog in the radiator didn't allow the fluid to circulate properly so at driving rpms the system didn't cool the engine properly cause not enough flow. The other thing is did you replace both thermostats? These vehicles have a second thermostat which they refer to as a water control valve. One is set to 185F and the other 205F.

Check the coolant temp with a OBDII scanner. My car normally stays below 200F while moving and only gets over 205F when sitting running and I live in AZ where the outside temp does nothing to help keep a car cool