If the radiator remains cold while the engine block is scalding hot, the thermostat is dead. Drain the coolant partially, unbolt the thermostat housing, install a new unit with a fresh gasket, and torque to specification. Install a New ECT Sensor
And sometimes, that’s exactly what hot means.
When a Fiat engine runs hot, it is trying to tell you that the heat generated by combustion is not being adequately dissipated. Top Reasons Your Fiat Is Running Hot