Hydraulic oil temperature beyond 82°C is likely to cause damage to your hydraulic system’s components and accelerate oil degradation.

As one of the most common issues in a hydraulic system, ensuring your hydraulic oil does not overheat is a priority to keep your machines healthy, and avoid costly downtime and repairs.

You can usually tell if the temperature is too high, as the viscosity will be too low for the hydraulic components.

Viscosity can also be negatively affected in temperatures below 82°, depending on the oil’s viscosity index. To ensure a stable oil temperature, the hydraulic system must be able to dissipate heat faster than it is built up. 

How to prevent overheating
Reducing hydraulic oil temperature and increasing the rate of heat dissipation are the two most common and effective ways to prevent your system from overheating.

Heat dissipation occurs in the hydraulic reservoir. Check your reservoir to ensure the fluid level is correct. If the fluid level is low, fill it to the recommended level. Whilst you are checking the oil level, make sure there are no obstructions, such as dirt or debris, preventing good air flow into the reservoir.

Heat exchangers
Heat-exchangers rely on the flow-rate and temperature of the hydraulic oil and the coolant in order to disperse heat efficiently. Once again it is critical that you regularly check for any debris or dirt, and ensure the core is not obstructed. If you experience issues with the cooling circuit then they may need to be replaced. Infra-red thermometers that check the performance and oil flow-rate of the heat exchanger can be used and are recommended.

Leakage
Excess heat can be generated when the pressure in a hydraulic system drops. Similarly, overheating can occur if any components are leaking. Check regularly for leaks and fix appropriately.