2000 Other Rover Models heating is not functioning

Heater problem
2000 Other Rover Models Engine Size unknown Wheel Drive Type unknown Manual 73000 miles

I HAVE A ROVER 45 SERIES 1.4.

I BOUGHT THIS TWO MONTHS AGO.

PROBLEM IS HEATER IS NOT WORKING EVEN I CHECK WATER LEVEL DAILY BASIS. I PUT WATER WITH ANTI-FREEZE. SOMETIMES IT WORKS. SOMETIMES IT WON'T FOR A LONG TIME.

ONE MECHANIC TOLD ME THAT THE HEAD GASKET MUST CHANGE. OTHERWISE, THIS PROBLEM WILL CONTINUE. PLEASE ANSWER ME WHAT TO DO.