4.2V8 overheats.

[Exerqtor]

This weekend my car started acting up on me, if i drive for say 30min the engine temp goes as far as 120C and the electric fan starts when it passes 115C(ish).

Popped the hood and held on the tubes going to the heating system and i could feel it boiling. Is this a problem that CAN occur if the PTC heat sensor for the electirc fan is good on these cars? Or am i looking at a failing thermostat?