On my boat the refrigerant line from the compressor to the cooling plate within the fridge was rubbing against part of the wood work resulting in a leak and loss of gas. I took the entire refrigeration compressor and cooling plate to my local refrigeration engineering firm where they found the leak, sealed it with solder and re-gassed the system. That was about three years ago and the fridge has run satisfactorily since then. However, it was not cheap, costing something more than £200. The woodwork where the chafe occurred has been cut away and the area protected with foam rubber to prevent it from happening again.