My fridge seems to be ok but the freezer part defrosts and refreezes of its own accord. There is also a smell (like old ice). And do CFCs have a smell?

jacqui o'connor, January 2008

CFC's have not been used in fridges since the early 1990's.
It is unlikley you have a gas leak because all fridges have a set amount in them, if it leaks, loss of cooling will occur but it can not return as they do not refill themselves. (bit like a puncture in your tyre can not reinflate itself).
Your fault sounds more thermostat/motor etc.

Tony Randall fridge Engineer, January 2008