Hydraulic Fluid Overheating Problems: What are the Common Causes?

Blog | October 3rd, 2019

Non-industry customers are always surprised when they hear that hydraulic fluid can get too hot. Surely, the oil should cool itself, they say. That’s not necessarily true, unfortunately. Hydraulic fluid overheating issues exist, that’s a proven fact. Moving on from this self-evident conclusion, the real question is what causes the thermal saturation. What’s the origin, the source of the heat? Only by knowing these common causes can we come up with a workable solution.

Cumulative Losses Cause Overheating Problems

Oil travels quickly throughout a mobile hydraulics machine. The fluid isn’t isolated, isn’t compartmentalized in a distant subsystem. Traditionally, this system attribute is perceived as a positive feature. If fluid force is required at a telescoping boom, then the energy is instantly available. That’s what makes hydraulic oil such an energy-responsive fluid, right? True enough, but there are losses and parts inefficiencies occurring all over the frame. Each tiny loss accumulates and adds up into one energy mass because the oil is such a good heat absorption base. To summarize, small system losses gather and accrue in hydraulic fluid streams. The losses accumulate as heat. If the gear is particularly inefficient, those losses cause a fluid overheating effect.

Pressure Drops and Tube Bottlenecks

When a wide diameter tube narrows into a thin rubber hose, heat is generated, for the oil is “squeezing” itself into less space. Better system designs minimize this phenomenon, but the impact of this fluid compressibility problem is felt again if the gear is placed under stress. Mobile hydraulics overloading incidents often translate to fluid overheating problems. Next, loose mechanical parts vibrate. As the vibrations propagate, the noise generates heat. Dissipated across a large machine frame, the energy can find its way into the force storing fluid. Moving on, pressure drops across actuators and valves generate thermal losses. If the pressure differential doesn’t produce mechanical work, then it’ll turn into an unmanageable thermal loss. Cumulative heat losses, loose parts, design bottlenecks, and pressure losses, all of these thermal effectors constitute a system threat.

As the temperature rises, the oil and frame dissipate the heat. At least that’s the theory. If the losses are too high, hydraulic fluid overheating problems will worsen. The oil might separate, the equipment seals degenerate, and the gear prematurely fail. Lift and transport responsiveness experience a performance drop because of a change in the oil’s viscosity. Maintenance techs can reverse these effects. Since the fluid reservoir collects the heat, they’ll make sure that the tank is full. With heat exchanger parts, they’ll check flow-rates and temperatures. Remember, the oil temperature has to stay below 80°C if the seal and hose components are to remain functional.

Mobile Hydraulic Specialties Pty Ltd

Factory 89, 38-40 Popes Road
Keysborough, Victoria, 3173

Phone: (03) 9798-6511

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Mobile Hydraulic Specialties Pty Ltd

Phone: (03) 9798-6511
Address: Factory 89, 38-40 Popes Road, Keysborough, Victoria, 3173