What is a common cause of sludge build-up inside the discharge line of air compressors?

Excessive oil passing the oil control rings is a common cause of sludge build-up inside the discharge line of air compressors. When the oil control rings fail or become worn, they do not adequately prevent oil from entering the combustion chamber. This can lead to oil mixing with the hot compressed air, resulting in the formation of sludge as the oil degrades and breaks down under high temperatures. This sludge can accumulate in the discharge line, which can negatively impact the performance of the air compressor and lead to various issues, including reduced efficiency and possible damage to the system.

In contrast, a coolant leak primarily results in issues related to engine coolant systems rather than directly affecting the discharge line of air compressors. Low tire pressure is unrelated to air compressor functionality, as it pertains to tire performance in vehicles, and clogged brake lines specifically relate to brake fluid pathways rather than air compressor operations. These other options do not directly contribute to sludge formation within the compressor's discharge system.