If you have an AMC engine, and are going by the little gauge in the speedometer cluster, don't sweat it.
The entire sweep of that gauge is about 25 degrees.
Mine swears the engine is melting down before the thermastat opens, and swears the engine is in a deep freeze after the thermastat opens...
If you are really worried, try a mechanical temp gauge.
They are a PITA to put in, but if you don't kink the capilary tube they will work, ACCURATELY, nearly forever.
Just one of those 'Jeep Quirks' we've all come to know and love [img]/ubbthreads/images/graemlins/wall.gif[/img]