What are the causes of excessive oil temperature in hydraulic systems?

[KylieMarie]

Hydraulic system oil temperature can become excessively high due to the following reasons: 1. Poor heat dissipation: The oil tank may be designed too small during the design phase, causing the oil to circulate too quickly, or the cooler may be ineffective in high ambient temperatures, both leading to poor heat dissipation. 2. Malfunctioning system unloading circuit: Typically, an unloading valve is installed at the pump outlet of the system. When the system is not under load and does not require pressurized oil, the system unloads to reduce energy loss. If the unloading valve malfunctions, oil may still return to the tank through the relief valve when pressurized oil is not needed, causing the oil temperature to rise. 3. Air or moisture entering the oil: When the hydraulic pump converts oil into pressurized oil, the presence of air or moisture can increase heat generation, leading to overheating. 4. Incorrect use of excessively viscous hydraulic oil: Oxidation of hydraulic oil or low ambient temperatures can increase viscosity. Hydraulic oil that is too viscous will increase friction, thereby generating heat.