Normally after use my car engine would not register temperature (below 60°C) after 1 hour. Why then on the weekend did it register approx. 75°C 6 hours after it had last been used?

A little extra information:

The keys were not in the ignition. It was overnight in Southern Norway, so not in a sunny or warm location. I was sleeping in the car all doors locked and closed. There was a noise similar to a pump/fan but difficult to make out because of background noise from ships in the harbour, and also a clicking noise.

It also happened earlier in the day. I recall smelling a fuel that my first impression was paraffin. I probably assumed this as I also heard a jet style noise, but then common sense prevailed as I doubt I would be close enough to a jet engine to smell the fuel without really knowing it was there. This time it did not register as warm as the later event but certainly 65°C or a little over, was parked in the shade, engine off for minimum 2 hours, and again no key in ignition. It was very quiet in this location so I definitely know there was a period when nothing was happening.The main difference to this event is that at least the back door was open.

Both times I started the engine soon after discovering the issue and it has started fine each time, and then run and cooled down as expected.

I've had a quick look to see if there is any sort of advance warming system on this engine, but nothing obvious is found and I doubt it likely on a lower end Ford.

what is happening, is it normal, should I be worried?

Thanks in advance.