1989 Other Volvo Models try to keep the engine cool

i got a 1989 volvo 340 and last week i had a new thermosat put in the cooling system and the temp gauge at the moment is showing a little over the middle mark and today i had a new water temp sender put in the engine and the temp is still showing a little over the middle mark which is the normal working temp mark. is it the termo fan switch is the fault or the radiator needs the clean