Question 33 OSE01 - Chief Engineer - OSV

The Correct Answer is D **Explanation for Option D (Correct Answer):** 1. **Draining while the oil is hot:** Lubricating oil, especially used oil, contains contaminants (like sludge, wear particles, and oxidation products). Heating the oil lowers its viscosity significantly. When the oil is hot, it flows more easily and carries more suspended contaminants out of the system during draining, ensuring a more complete removal of old oil and debris from the governor's reservoir and passages. 2. **Flushing with the lightest grade of the same type of oil:** Flushing is performed to remove any remaining traces of old oil, sludge, and contaminants missed during the initial drain. Using the lightest (lowest viscosity) grade of the specified oil type ensures maximum solvency and flow. The low viscosity allows the flushing fluid to reach tight clearances, dissolve sticky residues, and drain completely, leaving minimal residue behind before the new operating charge of oil is added. **Explanation for Incorrect Options:** **A) The governor oil should be drained while the oil is cold and the governor should be flushed with the heaviest grade of the same type of oil.** * **Incorrect:** Draining cold oil is inefficient as the high viscosity traps sludge and contaminants within the governor. Flushing with the heaviest grade is counterproductive; the high viscosity oil would leave residual coating and not flow well enough to effectively carry contaminants out. **B) The governor oil should be drained while the oil is hot and the governor should be flushed with the heaviest grade of the same type of oil.** * **Incorrect:** While draining hot is correct, flushing with the heaviest grade is incorrect for the reasons mentioned above (poor flow and residue buildup). **C) The governor oil should be drained while the oil is cold and the governor should be flushed with the lightest grade of the same type of oil.** * **Incorrect:** Draining cold oil is inefficient. While flushing with the lightest grade is correct practice, the initial drain must be done hot to properly remove the bulk of the used, contaminated oil.