What is one symptom of hydraulic fluid overheating?

Excessive foaming of the fluid is indeed a significant symptom of hydraulic fluid overheating. When hydraulic fluid reaches high temperatures, it can cause the fluid to lose its viscosity, which in turn leads to the formation of foam. This foaming can create an unstable hydraulic system, as it reduces the efficiency of fluid movement and can lead to cavitation within hydraulic components. Additionally, foamy fluid can result in higher energy consumption and increased wear and tear on the hydraulic system, ultimately manifesting as further operational issues.

Other symptoms, while they may indicate problems in a hydraulic system, are not specifically tied to fluid overheating. For instance, puddling around equipment might suggest a leak, a change in fluid color can indicate contamination rather than overheating, and increased fluid pressure can be a result of various factors unrelated to temperature. Thus, excessive foaming is the most direct indicator of overheating hydraulic fluid.