What factor is crucial for selecting hydraulic fluid?

Viscosity and temperature range are critical factors in selecting hydraulic fluid because they directly influence the performance and efficiency of a hydraulic system.

Viscosity refers to the thickness of the fluid, which affects how well it can flow and carry out its function in the system. A hydraulic fluid that is too viscous may not circulate properly, leading to sluggish performance and potential damage to components. Conversely, if the viscosity is too low, the fluid may not provide adequate lubrication, resulting in increased wear and tear.

The temperature range is equally important because hydraulic fluids can change viscosity as temperatures fluctuate. Selecting a fluid that maintains stable viscosity across the expected operating temperature range ensures the system operates efficiently and reduces the risk of hydraulic failure. If the fluid's viscosity fluctuates too much, it can lead to poor system responsiveness and potential damage during high or low-temperature operations.

Other factors like cost, availability, and even color or smell might be of secondary importance and typically considered after assessing the fundamental requirements related to viscosity and temperature stability.