I replaced my factory 76.5°c thermostat with the 82°c unit from Nissan.
I drained about 2L of coolant from the bottom of the radiator and that was enough to clear the thermostat housing.
http://www.nissanpatrol.com.au/forum...2020/10/66.jpg
On removal of the old 76.5 it appeared to be damaged.
The bottom looked bent and there was a scuff/indent on the base.
http://www.nissanpatrol.com.au/forum...2020/10/67.jpghttp://www.nissanpatrol.com.au/forum...2020/10/68.jpghttp://www.nissanpatrol.com.au/forum...2020/10/69.jpg
I'm not sure if it was having an effect on the temperatures.
Here it is in February this year on a day that was about 30°c, stationary, and it was sitting around 72°c.
http://www.nissanpatrol.com.au/forum...2020/10/70.jpghttp://www.nissanpatrol.com.au/forum...2020/10/71.jpg
Old thermostat.
http://www.nissanpatrol.com.au/forum...2020/10/72.jpg
New one.
http://www.nissanpatrol.com.au/forum...2020/10/73.jpg
I'll see how the new 82c one goes over summer as the weather warms up here in Vic.