5 Common Hydraulic System Failures Caused by Wrong Oil Selection

Hydraulic systems are needed in many industries. They supply motion and power to machines through hydraulic oil. This oil transmits force effectively throughout the system.

When hydraulic oil is selected incorrectly, it causes a chain of failures. These failures interrupt work processes and increase repair costs due to downtime.

Here, we are going to identify five common failure points caused by poor hydraulic oil selection to make decisions to choose the correct hydraulic oil for your system with clarity. 

What is Hydraulic Oil?

Hydraulic oil is a special fluid that transmits hydraulic power from the pump to the cylinders and motors. In fact, it also lubricates the moving parts inside the system to reduce friction.

These systems use hydraulic oil to transmit power and create fluid-based pressure between pumps, motors, and cylinders to operate. An incorrectly selected hydraulic oil interrupts this power transmission and leads to more breakdowns in the hydraulic systems and higher costs to repair.

So, when you choose the right hydraulic oil, it 

• Protects against rust, 

• Helps clean contaminants from the system, 

• And work well within the acceptable temperature range for the system's pressure ratings.

But when you choose the wrong form of hydraulic oil, it can cause one or more of these failures. The oil must meet the hydraulic system's performance requirements and temperature needs for fluent operations.

Why Choosing The Right Oil Matters?

Every hydraulic system has rules for the correct oil type. These rules come from the manufacturer's guide. Factors like temperature, load, and speed determine the right oil.

Wrong hydraulic oil changes how thick or thin the fluid stays when it gets hot or cold. This breaks the balance of power transfer and protection. Simple checks, like the correct viscosity grade, can prevent most issues as specified below:

Failure 1: Overheating

One of the biggest problems caused by the wrong hydraulic fluid is overheating. Hydraulic fluid must be strong enough to handle high temperatures. The hotter the fluid becomes, the thinner it gets, and the less efficient it is at cooling parts.

If a hydraulic pump or valve gets too hot, its operational life becomes much shorter. Excessive heat from improper hydraulic fluid can melt or crack seals. As a result, machines slow down or shut down to prevent further damage.

Using a hydraulic fluid that is too viscous (thick) in a high-temperature environment causes more wear on pumps. In fact, the pumps have to work harder to push the fluid through the system. The harder the pumps work, the more heat they generate. This becomes a continuous loop.

Early signs of wear include smoke or unusual sounds. You can reduce this wear by using a hydraulic fluid with a high viscosity index. This allows the fluid to flow properly from cold start-up to hot running conditions.

Overheating is the main cause of premature wear and tear on hydraulic machine components. Routine testing of hydraulic fluid for reduced viscosity is the best way to catch problems early.

Failure 2: Too Much Wear

Excessive wear happens when there is poor lubrication in the hydraulic system. With the wrong hydraulic fluid, system components rely on metal-to-metal contact for lubrication.

The most severe wear usually occurs in the hydraulic pump. Hydraulic pumps have very tight gaps between their components. Low viscosity (thin) hydraulic fluids flow through these gaps too easily and do not provide enough lubrication on the surfaces.

Dust and water can mix with poor-quality hydraulic fluid. This creates a grinding effect like sandpaper inside the system. Over time, this grinding scores the hydraulic cylinders. Once cylinders are scored, leaks develop. The system then loses power and needs replacement components soon.

Failure 3: Leaks from Bad Seals

Seals keep the hydraulic fluid in the right place. They expand or shrink depending on the type of hydraulic fluid used.

Rubber seals shrink and become brittle with thin hydraulic fluids. Thick hydraulic fluids make seals expand too much, which can cause them to tear.

Heat makes seal degradation happen even faster when using the wrong fluid. When a seal cracks, hydraulic fluid leaks all over the equipment. This can cause the equipment to run dry and lead to engine seizure.

Repairing and cleaning up leaked fluid wastes many hours. Low-pressure hydraulic systems cannot lift heavy materials or compress materials effectively in hydraulic presses.

To prevent future leaks, choose hydraulic fluids that are compatible with the seal materials (such as nitrile and Viton). Check the seals every time you change the hydraulic fluid. Also, remove any contaminants that can create openings for leaks around the hydraulic seal.

Failure 4: Pump Damage

Hydraulic pumps supply hydraulic fluid to the system. If the viscosity of the fluid is wrong, the pump cannot create enough flow.

If the fluid is too thick, the pump operates under high stress and high heat. This causes rapid wear on the gears or pistons.

With thin hydraulic fluids under heat, cavitation can occur. Cavitation creates bubbles that collapse and cause pitting on the metal surfaces. This damages the metal and requires costly repairs.

A pump that is about to fail makes a distinct whining noise. Repairs for a stopped pump are very expensive.

Failure 5: Sludge and Blockages

Over time, bad hydraulic oil turns into sludge. Varnish sticks to the walls because of the wrong additives. Filters get plugged first with this gunky sludge build-up. This reduces flow and causes pressure spikes.

The oil oxidizes quickly when mixed with air or water and starts to smell sour. Valves get stuck shut with brown deposits from bad oil. The system may jerk or stall during operation. Cleaning can take several days, and new filters are needed.

To prevent sludge formation, use clean oils with anti-foam additives. Change filters on schedule. Keep hydraulic tanks full to limit air mixing with the oil.

How Wrong Oil Starts These Problems

Many lifting companies buy cheaper oils without checking their specifications. They do not verify viscosity (ISO 32 or 46) or the temperature ranges suitable for their work location. Thin oil is needed for cold locations and thick oil for hot locations.

When adding new oil to old oil, make sure they are compatible. Otherwise, they react badly and create foam. Always flush the system completely before adding new oil. Check labels to see if the oil is mineral-based or synthetic-based.

Signs to Watch For

Signs of trouble are easy to detect if you stay alert.

• The burning smell means the oil is overheating.

• Milky color usually means water is mixed in the oil.

• Black and thick oil indicates sludge build-up.

A whining or knocking sound from the pump is a warning. Slow movement of the lift also shows trouble. If pressure gauges bounce wildly, there is likely a blockage in the line causing pressure build-up.

Log all signs and symptoms on a daily basis.

Conclusion

Selecting the proper hydraulic oil prevents these five common failures. It ensures efficient operation of your machinery for many years by matching the oil specifications with your hydraulic system's requirements.

Regularly check the hydraulic oil specification and train your personnel on proper hydraulic oil usage. This simple practice reduces costly downtime, increases equipment life, and improves productivity.

So, make proper oil selection the centerpiece of your maintenance program and your hydraulic system will give you dependable operation in return.