Grand Vitara Temperature Problem

Hi, I'm Ramón. I have a Grand Vitara of 2008 1.9 DDIS. Although the temperature needle remains in place of correct operation, the refrigerant is heated getting out of the circuit through the expansion bottle valve. Once the engine is cold when opening the refrigerant expansion bottle I observe that there is a lot of pressure inside.
I have also observed that water does not return to the refrigerant expansion bottle.
I have changed the thermostat, the water pump, the radiator and the Board of the butt, all new, and remains the same. Where can the problem be? Thank you.

And when you changed the cylinder head packaging they made the hydraulic test in a lathe to verify that the veins of the refrigerant are not covered