What is a common indication of refrigerant contamination in a compressor?

The presence of sludge in the oil is a common indication of refrigerant contamination in a compressor. When refrigerants become contaminated, particularly with moisture or other foreign substances, it can lead to the formation of sludge within the compressor. This sludge can accumulate and adversely affect the lubrication system, leading to increased wear and damage to the compressor components. As the contaminants mix with the lubricant, they can cause changes in viscosity and hinder effective lubrication, resulting in further operational issues and potential compressor failure. Identifying sludge is crucial for diagnosing refrigerant contamination and addressing it before it leads to severe mechanical failure.