Do you know the temp rating of your thermostat?  I know when I got my car
(a Saab 900), the thermostat it came with was a 92C, so thats the temp when
the stat opens to cycle the fluid through the engine and radiator, but an
82C was available so I went with that.  You may want to investigate going
with an 82C to keep the temperatures down within the engine.

I am assuming you are talking about a 406 Turbo Diesel.
Car temperature gauges are notoriously bad at providing the correct
temperature reading. You can only be sure of the gauge reading if you check
the water with a second temperature gauge.
The thermostat opens at 83 C.
The fans are controlled from an electrical system
Both fans operate in series at 96 C (slow)
Both fans operate in parallel at 118 C (Fast)
To check the fans do both work, with the engine switched on remove the brown
plug on the thermostat housing. After a few seconds both fans should come on
at high speed.
If your engine cools rapidly after reaching 90+ I would not worry.
Water in a radiator is pressurised to lower its boiling point. If you have a
leak in the cooling system it will affect the cooling system efficiency and
lower the boiling point of the coolant.

Mike

Thanks for your advice Mike, big help