Age of Fridge is not exactly known but is at least 30 years. Make and model unclear - it is a fridge freezer, fridge on top-, freezer below, height overall about 170 cms.. The part number of a flap on one of the freezer shelves is 112170. (It was replaced in 1990) Hope this helps - it is all that I have.
I assume it is the compressor. Something starts - a motor?- then runs for a few minutes in a pulsating mode before slowing and stopping - then restarts for a repeat performance, and so on. In a quiet room it is maddening!