I have a half sized commercial fridge that doesn't cool at all. The in and out tubes are both room temp. The lights work, fan works, compressor runs. There is only a thermostat, motor protector and relay attached to the wiring. No capacitor as far as I can tell. When the compressor runs I can hear liquid moving a little bit and I can hear it after I unplug it. So, there is something in there. Is it possible that it's just oil in there making noise and that the coolant has leaked out?

Any help would be appreciated.

Also, it's one of these:

Thanks it was the thermostat control on fridge side that was not working. Order new one already.