Originally Posted by michalm5
after running it, u turn on the ignition again and it shows less than half, and than jumps to over hot, coolant ok, not that much heat under the hood
e39 has electronic thermostat designed so that software in vehicle displays centre mark when temperature is within BMW normal specs for driving.
Actual temperature may vary, but as long as within acceptable levels it will show needle in the middle.
Nothing to worry about, perfectly normal.
If it goes to 3/4 then have inspected.