What effect do oil contaminants have on turbine engine life, and what maintenance actions mitigate the risk during an overhaul?

• A. Contaminants have no effect on engine life.
• B. Contaminants cause bearing wear and clogging; actions include filter changes, oil system flushing, line cleaning, and component replacement as needed.
• C. Contaminants improve oil viscosity and reduce wear.
• D. Contaminants only affect fuel system, not oil.

Answer: (B)

Oil cleanliness directly affects turbine engine life because contaminants act as abrasive particles that wear bearings, score surfaces, and clog oil passages, which reduces the lubricating film and accelerates wear. When particles are present, those tiny stresses accumulate in critical bearings and gears, leading to premature bearing failure and reduced overall life of the engine.

The best answer captures both the mechanism and the remedy: contaminants cause bearing wear and clogging, and maintenance actions during an overhaul include changing filters, flushing the oil system, cleaning lines, and replacing components as needed. Filter changes remove the majority of particles, flushing and line cleaning scrub out sludge, varnish, and residual contaminants that can harbor in oil passages, and replacing worn parts restores clearances and proper lubrication pathways. Together, these steps restore oil system integrity and minimize the risk of continued contamination harming engine life.

Other choices miss the direct link between oil contamination and lubrication problems. Contaminants do not improve viscosity or wear; and they do not affect only the fuel system while leaving the oil untouched.