There has to be oil sightglass somewhere. What's happening in there when the comp runs ?
calm 3/4 full ok
foaming top level visible double check
full sightglass is not good either
a few more answers will help too
Freezer suction lines only have to be at 25* F and they'll make ice easily with no liquid.
less humidity would lower the frost too
make sure U stick to your guns when U make a call