Yes, hydraulic fluid can go bad over time. Like any other fluid, hydraulic fluid can degrade and lose its effectiveness due to various factors such as oxidation, contamination, and temperature fluctuations. Oxidation occurs when the hydraulic fluid reacts with oxygen in the air, causing it to thicken or become sludgy. This can lead to reduced lubrication properties and increased friction within the hydraulic system. Contamination from dirt, debris, or water can also deteriorate the fluid, causing it to lose its viscosity and flow characteristics. Temperature fluctuations can accelerate the degradation process of hydraulic fluid. High temperatures can cause the fluid to break down chemically, resulting in reduced performance and potential damage to system components. On the other hand, low temperatures can cause the fluid to thicken, leading to poor flow and reduced hydraulic efficiency. Regular maintenance and periodic fluid analysis are essential to determine the condition of hydraulic fluid. If significant degradation is detected, it is recommended to replace the fluid to ensure optimal performance and longevity of the hydraulic system.