when the system is not running the compressor needs to be kept above the condensing temperature/pressure of the refrigerant in use to prevent the refrigerant from migrating to the compressor

both oil and refrigerant have an upper limit for temperature and when exceeded will begin to break down their molecular composition and there fore they should always be kept within their design spec

you will need the data sheet for the exact oil used to check its designed temperature range

for refrigerant you can see this on a pressure enthalpy chart