Oilers/Plant Tenders (HHC) Civil Service Practice Exam

Which of the following statements is true about oils used for air compressor lubrication?

1. They should contain approximately 40% dark cylinder oil

2. They should contain approximately 30% dark cylinder oil

3. They should be free of dark cylinder oil

4. They must always be synthetic oils

The correct answer is: They should be free of dark cylinder oil

The statement that oils used for air compressor lubrication should be free of dark cylinder oil is correct. Dark cylinder oil generally has specific properties, such as high levels of additives for anti-wear and extreme pressure protection, which can negatively impact the performance of air compressors. These oils may not provide the optimal lubrication required for the internal components of air compressors, which often need oils formulated for lighter workloads and specific viscosity grades to ensure proper functioning and efficiency. Air compressor lubricants should be carefully selected to minimize residue formation and avoid carbon buildup, which can occur with oils that have heavy, or dark, additives. Therefore, ensuring that the lubricant is free from dark cylinder oil is critical for maintaining the integrity and longevity of air compressor systems. Options that suggest including specific percentages of dark cylinder oil or solely using synthetic oils do not align with the best practices for lubrication in air compressors, where a clean, lighter oil is preferred for optimal performance.