Well mine goes up to near the middle so not sure what may be wrong with yours?
You could see if the needle is sticking by testing all the needles in the test mode.
With the car switched off, press and hold the mileage tripreset button and switch the key to position II. This hould put the car in test mode and the first thing it will check is all the dials. They should all sweep fully to the right and then back then reset to normal.
Or the thermostat sticking partially open. Or you have a slight airlock in a part of the system. Do both radiator and heater get any heat to them at all
you could always try just letting it idle for a while till the electric fan cuts in to check that the whole system will get up to temperature and then see where the needle is (it ought to be more than ¾ up the scale
I havent touched the radiator so cant comment although i'll take it out for a spin at lunch and test it. I've noticed that mine seems to sit right on the 1/4 line mark and doesnt go any higher than this.
Its still under warantee form the garage a bought it from so i'll take it back there for a fix.
In all these cases has anyone let the engine idle once warm until the engine fan cuts in and then noted where the temperature gauge needle is. If this is before the gauge goes into the red and when the fan switches off the gauge is back down to the normal position then it probaly doesn't matter because you then know whenthe gauge is indicating a temperature related problem