All of the following are symptoms of a refrigerant leak EXCEPT:

A cold compressor is not a symptom of a refrigerant leak. Typically, when there is a refrigerant leak, the compressor may struggle to maintain adequate pressure and temperature levels, leading it to overheat rather than remain cold. The compressor relies on sufficient refrigerant to operate efficiently and effectively; a leak would generally result in higher temperatures within the compressor as it gets overworked trying to compensate for the lack of refrigerant.

In contrast, low efficiency, a long-running cycle, and the presence of oil on fittings are common indicators of a refrigerant leak. Low efficiency occurs because inadequate refrigerant results in poor heat transfer. A long-running cycle happens when the air conditioning system cannot reach the desired temperature due to insufficient refrigerant levels, thus causing it to operate longer than normal. Oil on fittings is also a strong indicator, as refrigerant leaks can carry some lubricant with them, leaving an oily residue where the leak has occurred.