rover 400 1.4i?

hi, ive replaced a engine on my rover 400 1.4i after the head gaset went but the problem is that when the car is idling the water in the engine coolent resvoir over heats but the temp gauage inside the car is normal but the blower in the car does not give out heat,the thermostat ant the fan seem to be working.can any one advice me!

jake