Twice the temperature pointer achieved the maximum and began to expel water from the reservoir that feeds the radiator

Question

I am owner of an 1999 Range Rover 4.0SE.  The  temperature pointer achieved the maximum 4 five minutes and began to expel water from the reservoir that feeds the radiator. I changed the board cuple and all associated rings. I also changed the spark plugs and water pump and thermostat but the symptom remains.