I seem to be having my second failure of a chest freezer
used as beer cooler. The failure mode is that the unit runs
continuously but doesn't get the temp to drop more than
a few degrees. It also seems quieter when running after
failure

The space it is in in my basement is currently about 55F.
The temp controller is a mechanical thermostat with
the sensing bulb passing into the unit between the lid
gasket and the top of the chest wall. The thermostat controls
the power to the compressor through a relay. The temp is
usually set to 35-40F.

Both units were obtained used for cheap or free, so maybe they
were just worn out. They seemed to work fine for awhile.
Each lasted a year or so.

Has anyone else had similar problems? Is there something that
I am doing that is killing the freezers?

Bob F