Alex_M thanks again for the urls

 

It is likely you have no real problem. I remember my D2 V8 temp. gauge always sat at 3/4 but the engine was within normal range when checked with Nanocom. Even after more than an hour being parked up the engine would still be warm to hot and this is in Northern Ireland.
The only time my gauge hit the red was when it really did over heat due to the failure of my Kenlowe electric fan. With this fan fitted I ran my engine at 85ºC (185ºF) with no ill effects.

 

For $60, an UltraGauge will tell you everything you need to know while driving. They are highly recommended on here. Engine temp is the main reason I got one.