What occurs in the hydraulic pump if the oil tank is insufficiently filled and air enters?

When the hydraulic pump experiences insufficient oil levels due to an inadequately filled tank, air can enter the system. The presence of air in hydraulic fluid is detrimental and can result in cavitation, where vapor bubbles form in the fluid. As the pump operates, these bubbles can collapse violently, producing noise, which is often described as a "gravel" or "marbles" sound. This noise is an indication that the hydraulic pump is not functioning optimally due to the loss of hydraulic fluid's ability to create consistent pressure.

Moreover, the introduction of air disrupts the hydraulic fluid's ability to lubricate and transmit pressure effectively, potentially leading to further operational issues like inefficiency and risk of damage. Therefore, noise is a significant symptom of air entering the hydraulic system, highlighting the need for adequate fluid levels to maintain proper function and prevent damaging effects on the pump and overall system.