A technician is performing a daily pre-shift inspection on a large excavator. They notice a significant drop in the hydraulic oil level on the sight glass, with no visible external leaks. The last oil change was performed 200 hours ago, and the manufacturer specifies hydraulic oil changes at 1000-hour intervals. What should be the most immediate action?

Question: A technician is performing a daily pre-shift inspection on a large excavator. They notice a significant drop in the hydraulic oil level on the sight glass, with no visible external leaks. The last oil change was performed 200 hours ago, and the manufacturer specifies hydraulic oil changes at 1000-hour intervals. What should be the most immediate action?

Answer options:

• Top up the hydraulic fluid to the correct level and continue operation. ✅ Immediately shut down the machine and investigate for internal hydraulic leaks.
• Schedule a hydraulic oil and filter change, as the oil must be degraded.
• Record the low level and monitor it over the next shift.

Correct answer: Immediately shut down the machine and investigate for internal hydraulic leaks.

Explanation: A significant, unexplained drop in hydraulic oil level without external leaks suggests an internal leak within the system, potentially contaminating other systems or causing component damage. Continuing operation or simply topping up could lead to catastrophic failure. An oil change is not directly related to a sudden drop in level.