Outer Limits 4x4 Board

gudday!!!! just a few questions for people on this mighty informative forum!!!!
I have a 84 MK sd33T at the last nissan trials I thought I must of got some mud in radiator on the drive home to canberra it was running hotter than normal....
replaced thermostat all ok
flushed radiator all ok
cleaned mud from radiator all ok
new engine fan non clutch type so constantly sucking air all ok
new coolent all ok

I have two temp gauges one original factory thats never been touched and an after market gauge with temp readings wich is very accurate tested it with boiling water and it read 100c
my question is whats normal running temp ?????????
at idel the factory gauge now reads half way and after market gauge reads 85c
when I drove it hard and I mean hard 16psi boost up long steep hill foot flat to the boards 35c day holding 100kph the factory gauge just hit 3/4 but the after market gauge never went above 95c no matter what i did the after market gauge never went over 95c.........
can factory gauges stuff out with age????????
are these ok running temps?????????

Temp seems more than fine to me

Bazzle

Hi,
My MK on a trip to the Spring 4X4 park reach between 3/4 to just under Very hot on the factory gauge while going over the Cunningham Gap.
I have done the same check as you have thermosat, water, coolant, etc.
I also fitted at aftermaket gauge and it never reach over 105 deg on long trip.

There was an early thread mentioning the same problem with the factory gauge and they all said that it would read very high but the temp in the water was still ony 98 deg