If a refrigeration system compressor crankcase is exhibiting an unusual degree of sweating or frosting and is operating noisily, what should be done?

Correct Answer: Option C — check the evaporator superheat

Crankcase sweating and knocking noises indicate liquid refrigerant flooding back into the compressor cylinders. The marine engineer must immediately check and adjust the evaporator superheat to ensure complete vaporization before suction.