Question 31 3AE01 - Third Assistant Engineer

The Correct Answer is B **Explanation for Option B (Correct Answer):** Oil bath air cleaners rely on an oil reservoir to trap airborne contaminants (dust, soot, metal particles, etc.) before they enter the engine intake. The manufacturer's recommended frequency (e.g., based on hours of operation) is set for standard operating conditions. 1. **Dusty Conditions:** When the engine is exposed to significantly dirtier-than-normal air (e.g., during shipyard work, heavy cargo handling, or specific maintenance like arc welding in the engine room), the air cleaner oil will accumulate contaminants much faster. To maintain effective filtration and prevent dirt carryover into the engine, the oil must be replaced *more frequently* than the standard schedule. 2. **Oil Condition (Dirty or Thickened):** The primary purpose of replacing the oil is removing trapped dirt. If the oil is visibly unusually dirty, saturated with dust, or has thickened due to high contamination levels, its effectiveness as a trapping medium is severely reduced. Allowing this condition to persist risks damaging the engine. Therefore, the presence of unusually dirty or thickened oil mandates immediate replacement, overriding the standard schedule—meaning replacement should occur *more frequently*. Both conditions require proactive, increased maintenance frequency (more frequent replacement) to protect the engine. **Explanation of Incorrect Options:** * **A) Incorrect:** This option suggests replacing the oil *less frequently* when exposed to dusty conditions. Dusty conditions dramatically increase the contamination rate, necessitating *more frequent* replacement, not less. * **C) Incorrect:** This option correctly identifies the need for *more frequent* replacement in dusty conditions but incorrectly suggests replacing the oil *less frequently* when the oil is unusually dirty or thickened. An unusually dirty or thickened oil condition is the strongest indicator that immediate replacement is needed, requiring *more frequent* deviation from the schedule. * **D) Incorrect:** This option incorrectly suggests replacing the oil *less frequently* in both dusty conditions and when the oil is dirty/thickened. Both scenarios represent heavy contamination loads that necessitate *more frequent* maintenance to prevent engine damage.