Technical Overheating Punto 55s

[ne_ne83]

My 55 is overheating but it does not have a temp gauge and the red light has yet to come on.When i open the bonnet there is a hissing from the radiator.Should i worry
:bang:

 

[dave]

welcome to the forum
is the cap tight?

 

[ne_ne83]

Cap is tight,but i have now removed thermostat and when its cold the pin does not go back in.Its not overheating now though.