Good evening friend, in fact, most likely there is some refrigerant leakage, in this case it would be best to measure the working pressure when the refrigerator is turned off and once started, it could also be happening that there is some partial obstruction in filter drier and / or capillary tube; in both cases, the working pressure when the refrigerator is on will go empty, that is, below 0 psi, if once the refrigerator is turned off it takes a long time to recover the pressure, it is very likely that there will be obstruction; in case the pressure of the refrigerator being turned off is less than 30 psi if you use R134a refrigerant, it is very likely that there will be a refrigerant leak; on the other hand, the worst thing that could happen is that the engine is decompressed and has lost performance, in this case the working pressure will be higher than normal, but it will not cool properly, to discard this diagnosis a vacuum test must be performed to the compressor to verify its mechanical integrity.