Good morning my name is ***** ***** I will assist you with your query today.
I see you posted the same question, this has been closed as a duplicate to ensure your not double charged.
The model ZI3165 is no longer available for purchase, which part of the cabinet is getting warm (the back, sides roof)?
Sorry for the delay in responding, the fault is most likely the thermostat has failed, with regard to a fire hazard I cant say for sure its safe, its unlikely to cause an issue however if the appliance isnt keeping cold there is not benefit keeping it on.
Overally due to the age of the appliance I would look to replace it, however if you would like me to recommend an engineer to come out and repair it please provide your postcode.