Skip to content
Clogged Hydraulic Filter Symptoms and Causes

Clogged Hydraulic Filter Symptoms and Causes

A hydraulic filter being installed in a piece of heavy construction equipment

Clogged Hydraulic Filter Symptoms and Causes

Reading time: 5 min

A machine’s hydraulic system plays a vital role in its operation, providing incredible power, efficiently and reliably. At the heart of the hydraulic system are hydraulic filters, critical components responsible for maintaining the cleanliness and purity of the hydraulic fluid.

Hydraulic filters are designed to remove contaminants and impurities from the hydraulic fluid, ensuring smooth and reliable performance while protecting sensitive components from becoming compromised.

In most machines, hydraulic filters come in metal canisters which house a filter medium. These filters are commonly located near a machine’s hydraulic tank or in its engine bay. The exact location of your machine’s hydraulic fluid filter can be found in its service manual.

Over time, it is normal for hydraulic filters to become clogged. When a hydraulic filter has become clogged, the filter medium can no longer efficiently remove contaminants from the hydraulic fluid, and your machine’s hydraulic system may begin to malfunction.

Knowing how to spot the signs of a clogged or failing filter is essential to maximize the lifespan and efficiency of your machine.

Clogged Hydraulic Filter Symptoms

A clogged hydraulic filter can have negative effects on the performance and longevity of heavy equipment. Therefore, it’s critical to recognize the signs of a potential hydraulic filter clog so that the filter can be replaced before causing further damage to the machine.

  • Decreased Flow Rate: Flow rate refers to the speed with which hydraulic fluid moves through a machine’s hydraulic system. One of the main signs of a clogged hydraulic filter is a noticeable decrease in the flow rate of hydraulic fluid.
  • Drop in Pressure: Another telltale sign of a clogged hydraulic filter is a drop in hydraulic fluid pressure. As the filter becomes clogged, the restriction of fluid flow can cause a drop of hydraulic pressure in the system and a drop in power output.
  • Unusual Noises: A clogged hydraulic filter can generate unusual noises. These noises may include whining, rattling or grinding sounds. These sounds occur due to the increased strain on the hydraulic components, which can occur when the clogged filter restricts fluid flow.
  • Sluggish Machine Performance: When a hydraulic filter becomes clogged, heavy equipment may exhibit sluggish performance. Operators may notice slower response times, reduced power and decreased efficiency.
  • Hydraulic Leaks: In some cases, a clogged hydraulic filter can lead to hydraulic leaks. As the filter becomes overwhelmed with contaminants, it can no longer capture them and remove them from the fluid. This can lead to excess pressure in the system, leading to leaks at various connection points or from the filter housing.

By recognizing the signs that a hydraulic filter has become clogged, you can optimize equipment performance and reduce repair costs.

What Causes Hydraulic Filters to Become Clogged?

Hydraulic filters are designed to remove contaminants from hydraulic fluid, ensuring the smooth operation and longevity of heavy equipment. That being said, several factors can cause hydraulic filters to become clogged.

Proper maintenance and repair are essential to prevent excessive filter clogging, and can help extend the life of your filters. Here are some common reasons for hydraulic filter clogs:

  • Replacement Frequency: As they capture contaminants from a machine’s hydraulic fluid, hydraulic filters become clogged with debris. One common cause of a clogged hydraulic filter is age. While replacement frequency will vary according to a machine’s make and model, most hydraulic filters need to be changed every 1,000 hours.
  • Contaminated Hydraulic Fluid: Hydraulic fluid that has become contaminated through improper storage can cause hydraulic filters to become clogged prematurely. Therefore, it is crucial to only use clean hydraulic fluid that has been stored according to best practices.
  • Improper Seal Maintenance: Many components in the hydraulic system, such as its seals, are designed to prevent the ingress of debris into the system. When the hydraulic system and its seals have become corrupted, debris may make its way into the system, clogging the hydraulic filter prematurely.
  • Inadequate Pre-filtration: Insufficient pre-filtration or the absence of effective filtration upstream of the hydraulic filter can result in larger contaminants bypassing the filter media, reaching and clogging the hydraulic filter more quickly. Proper installation and maintenance of pre-filters or strainers can help alleviate this issue.
  • Harsh Operating Environment: Operating heavy equipment in dusty or highly contaminated environments, such as construction sites or mining operations, may result in hydraulic filters becoming clogged sooner. Increased exposure to airborne particles such as dirt, debris, silica, metal particles and water causes the filters to degrade more quickly.

What Happens if You Don’t Replace a Clogged Hydraulic Filter?

Failing to replace a clogged hydraulic filter can have detrimental consequences for your machine in both the short and long term.

Specific machine components directly affected by a faulty hydraulic filter include hydraulic pumps, which may experience reduced efficiency and increased risk of failure. Valves and cylinders can also be hindered in their responsiveness and overall performance, leading to imprecise control and reduced output. 

In the short term, reduced hydraulic fluid flow and pressure can lead to sluggish machine performance and reduced efficiency. Over time, not replacing a clogged filter can cause irreversible damage to the hydraulic pumps, valves, cylinders and seals.

Eventually, a thoroughly clogged hydraulic filter may lead to leaks in the hydraulic system and system failure.

Final Thoughts

For your machine’s hydraulic system to function properly, it must be well maintained. One of the most critical aspects of hydraulic system maintenance is changing hydraulic filters regularly.

In addition to changing filters regularly, other measures should also be taken to ensure the hydraulic system is well maintained. This includes things like changing seals and gaskets on time, and frequently inspecting the hydraulic system for leaks.

Although it takes time and effort to maintain a machine’s hydraulic filters, it is a maintenance task that pays real dividends in the long-run, enhancing machine performance and maximizing productivity on the job.

If you’re in need of a replacement hydraulic filter, the EquipmentShare Shop has you covered. Check out our selection of OEM and aftermarket hydraulic filters to find the right one for your machine. Can't find what you're looking for? Contact one of our parts experts and get personalized assistance.

Back to Parts In Depth

Are you signed up for our newsletter?

We'll send you a monthly email covering everything from specialty parts to machine overviews, packed with tons of knowledge from our industry pros and no filler.


Building Blocks Blog
Previous article What Is a Slew Bearing and How Does It Work?
Next article Symptoms of a Bad Diesel Fuel Injector: Causes and Effects