Feeling Hot, Hot, Hot: Troubleshooting Common Hydraulic Overheating Problems

When it comes to operating hydraulic equipment safely and efficiently, heat is perhaps your greatest enemy -- a hydraulic system that runs too hot causes excessive wear and tear and can cause hydraulic oil to lose its viscosity and, by extension, its lubricating properties. Letting a hydraulic system run too hot for too long can cause terminal system failure, an expensive and potentially dangerous prospect. Fortunately, the causes of overheating are often relatively simple, and professional hydraulic services can provide a number of fixes to keep your hydraulics running smoothly and coolly. Here are a few of the most common problems that cause overheating, along with ways they can be tackled:

Wear and tear

One of the most common causes of overheating is simple wear and tear as internal surfaces wear down and old oil starts to separate. As cylinder components wear away, the risk of oil bypassing the piston entirely increases -- this causes a dramatic pressure drop inside the cylinder, which can cause temperatures to rise alarmingly quickly. Happily, in most cases simply replacing worn components can solve the problem, and many hydraulic service companies can fabricate new components themselves to ensure the best possible fit for your new parts.

Having said that, you should take care not to go around replacing every part of your system that runs a little hot, as some parts of a hydraulic cylinder system (such as flow controllers) will naturally run hotter than others. Keep a record of how much heat is generated at various points in your system, and consider replacements when a component starts getting noticeably hotter than usual.

Check your reservoirs

The reservoir of a hydraulic system doesn't just hold your oil -- it also acts as an efficient heat sink, drawing heat away from moving components and allowing it to dissipate. However, a reservoir is only as effective as the hydraulic oil it contains, and a reservoir that is under-filled or contains perished oil will have its heat-reducing properties drastically curtailed.

Generally speaking, keeping your reservoir filled with oil and replacing old oil as it perishes is enough to solve this problem. However, larger hydraulic systems often use dedicated heat exchangers to increase the cooling efficiency of their reservoirs -- if this applies to your system, check your exchangers for blockages and remove any buildup of debris that occurs around the vanes. You should also make sure the reservoir itself does not contain excessive sediment deposits.

Unsuitable modifications

Hydraulic systems are built to exacting tolerances, but this does not save many systems from unsuitable and potentially dangerous modifications ostensibly designed to increase efficiency. For instance, many systems are fitted with more efficient flow controllers, designed to increase the rate of oil injection and increase piston speed, without having stronger, wider hoses and valves fitted to accommodate this increase in pressure. Improperly configured relief valves can also cause overheating problems, as can installation of excessively fine filters. 

As such, it's always safest to stick strictly to the manufacturers specifications when using a hydraulic system. If your system does require upgrades, have them done by professional hydraulic servicemen, as they will be able to accurately assess the scale of the modifications required.