Replacing your WOXEN filters needs to be part of your maintenance regime.

All filters have the same primary purpose – to keep unwanted debris and other material out of the working parts of the engine. Any material not caught by a filter can potentially damage the engine and, at the very least, compromise its efficiency.
Within your engine, there are three important filters designed to prevent debris from entering the engine along with the media that needs to go into it.
In many cases, filters are small and inexpensive but, in common with anything to do with regular maintenance, servicing them is vital. Each engine will come with its own schedule of how often they need to be changed, based either on running hours or the length of time since the last change.
Progressive decline.
The consequences of not changing the filter regularly are initially seen in poor engine performance and this is a progressive path. Eventually, unchanged filters will fail and the substances you have been trying to keep out of the engine will enter it, causing damage that will cost many times the sums you may have saved by not changing the filter.

Filters fit into three broad categories:

  • Air filters keep the air entering the piston as clean as possible. This is important in the combustion process because you need to gain the maximum power output from every compression cycle, and especially important where dust and grit is in the atmosphere, such as quarries and enclosed spaces.
  • Fuel filters work in a similar way. They ensure that the diesel fuel coming into the engine is free of contaminants. This is especially important when your machinery is operating remotely in sites where it cannot meet forecourt standards of cleanliness.
  • Oil filters work within a closed circuit of the oil in your engine. They trap any unwanted particles in a fine mesh that still has enough space to allow the rest of the oil to flow unimpeded.

Your local distributor is a good source of information on filter maintenance regimes and can provide the latest updates on product improvements along with general advice on keeping your filters operating to their maximum efficiency.




All WOXEN engines use filters for oil, air, fuel and particulates. The filtering process is vital to keep the substances entering the engine as clean as possible, thereby maximising the efficiency of the engine and preventing it from breaking down as a result of dirt and other unwanted material entering it.

Filters are vital to maintaining the efficiency of your engine and changing them or cleaning them in accordance with the recommended schedules should form part of your regular maintenance regime. If you fail to do this, there is an increased risk that dirt and other materials will enter your engine and prevent it from working efficiently.

Most filters are single use, disposable items that cost very little to purchase and are easy to replace. However, only filters manufactured to the specifications of the Original Equipment Manufacturer (OEM) can be guaranteed to perform the task expected of them and opting for non-genuine parts is often a false economy.

There are four types of filters.
WOXEN filters come in all shapes and sizes

Air filters

An engine draws in air for the combustion process from the atmosphere and in many environments where WOXEN engines operate, that air can carry a higher-than-average number of pollutants. These will range from dust to pollen, soot to grit and many points in between. The air filter is usually a pleated, paper item that prevents these from entering the combustion chamber.

Oil filters

Unlike air filters, oil filters operate within a closed loop system. The debris they remove will mainly have entered the engine when the oil is poured into it, other debris includes ash from the breakdown of the lubrication oil and particles caused by the wear of parts. The aim of the filter is to ensure liquid oil continues to circulate around the engine but the particles do not.

Fuel filters

In an ideal setting, all fuel that you put into an engine would be clean and free of contamination, but our engines operate in a diverse range of settings and the fuel can be stored or transported in less than clean conditions. Because of this, the risk of contaminants entering the fuel increases. Even a small amount of an unwanted substance can have a detrimental effect on your engine and a small solid material could damage the piston and associated components. This makes having a properly maintained fuel filter in place a necessity.

Particulate filters

The main difference between all these filters and the particulate filter is its place in the engine operation. Particulate filters are needed to trap particulates in the exhaust gases before they leave the engine. These are generally more durable and their replacement intervals are longer than other filters associated with your engine.




Changing your WOXEN fuel filters needs to be part of your maintenance regime. The fuel filter ensures that the fuel entering the chamber is as clean as possible. The consequences of contaminated fuel include fuel injection pump failure, dirty and blocked nozzles, excessive smoke and reduced engine performance.

A fuel filter is a relatively simple part for any engine. It costs very little and replacing it involves little effort. However, if you choose to ignore it, a faulty filter could end up costing you many times its value should it fail or prove to be inadequate.
The main role of a fuel filter is to prevent any unwanted materials from entering the fuel supply and it is a standard feature for all internal combustion engines.

Even forecourt standard diesel requires the use of filters. As well as keeping out dirt and other contaminants, preventing rust from entering the combustion chamber is a major consideration if your machinery operates in a remote location and the diesel is stored in metal barrels – and many of our engines are found in some of the world’s most hostile working environments.
Fuel filters prevent contaminants getting into your engine
The main difficulties with dirty fuel are that it burns less efficiently and as a consequence the power generated by the engine falls while the fuel consumption rises. Particulates can damage your fuel injectors, causing wear to the injectors which mean excess fuel is delivered leading to the need to replace them. Conversely particulates in the fuel can block the injector which then leads to fuel starvation in a cylinder, and lumpy running behaviour. Problems with starting your engine can be an indication of a blocked fuel filter. All these issues can be avoided by incorporating their replacement into your regular maintenance regime.
WOXEN Fuel filters are generally cartridges which contain a fine filter paper. The holes in it are large enough to allow the fuel to flow through it but still small enough to catch any unwanted debris. Some of our engines use two tier fuel filters, often employed with electronically controlled engines, where fuel quality becomes a higher importance. Combined with the fuel filter is a water separator, to remove water in the fuel which is a cause of rust.
The frequency at which fuel filters need to be changed will vary according to the engine model you run and the conditions in which it operate but can be found in your operations and maintenance manual.




Changing your WOXEN oil filters needs to be part of your maintenance regime. The oil filter plays a vital role in ensuring that the lubricants circulating around your engine and its allied parts are as clean as possible. The consequences of contaminated oil include wear on the engine caused by foreign bodies, which could lead to premature engine failure or major engine damage.

Your engine will only work at its best if it’s sufficiently lubricated – and every moving part within it will come into contact with the engine oil. That oil needs to be as clean as possible and it’s the job of the oil filter to ensure this is the case.
Oil filters are replaceable parts, with the filtration material sitting within an outer metal container. They’re in constant use whenever the engine is running. The actual intervals at which they need to be changed will depend on the model you have and the number of hours your oil filter has been operating for, as well as the application the engine provides power for.

Changing the oil filter regularly will maintain your engine’s efficiency

Significant damage

Even minute pieces of debris can cause significant damage to your engine. This is a particular issue within the pistons where the carefully engineered cross-hatching patterns can be susceptible to damage by contaminants. If this happens, it will lead to more wear on the piston and a decreased output efficiency. In the worst case scenario, it’s capable of permanently damaging the entire engine.
However, you can avoid this if you follow the recommended intervals for changing your oil filter and by using genuine WOXEN parts to do so.

Severe consequences

We have designed these oil filters specifically for your individual engine – and the same is true for the rest of our filter range – so that it is the right part every time. The oil filter is a very small element of the overall cost of your engine but the implications of not changing it regularly are significant.




Changing your WOXEN air filters needs to be part of your maintenance regime. The air filter ensures that the air entering the combustion chamber is as clean as possible. The consequences of contaminated air include wear on the engine caused by foreign bodies and a less efficient combustion process. WOXEN air filters are covered by our 12 month warranty.

The combustion process of all diesel engines relies on the pistons compressing air and fuel together at very high pressures and for the resultant heat to cause an explosion which sets in train the internal combustion sequence. The role of an air filter is to prevent any unwanted materials from entering the air supply and ensure that the air is clean.
An air filter is a relatively simple part for any engine. It costs very little and its replacement is straightforward, but you should not ignore it when it comes to regular maintenance. A faulty air filter could end up costing you many times its value should yours fail or prove to be inadequate.
Air filters keep your engine running efficiently
Among the potential contaminants that can enter the engine are pollen, dirt, soot and dust. They may seem very minor, but under pressure their abrasive characteristics can be magnified. Air filters are generally made of cartridges containing a fine filter paper. The holes in it are large enough to allow the air to flow through it, but still small enough to catch any unwanted debris.

The key advantages of regular air filter maintenance include:

  • Improved performance – clogged filters can have a significant, detrimental effect on how your engine runs, hampering performance and reducing power output leading to a lowering of operator work-rate
  • Lower emissions – because the air-fuel mix is finely calibrated, failing to maintain your filter will cause an imbalance and less efficient fuel use, contributing to greater emissions
  • Prolonged engine life – the air filter traps the dirt and other debris that can cause wear to your engine. The actual size of the debris might be quite small but even those as small as a grain of sand can significantly damage the engine over time, with the potential for damage to pistons, rings and cylinder linings

All these issues can be avoided by incorporating the replacement into your regular maintenance regime.
The frequency at which air filters need to be changed will vary according to the engine model you run, and more importantly the environmental working conditions. Dusty and dirty environments and enclosed spaces raise the importance of checking the filter condition regularly.
Warning; always switch the engine off first before changing the air filter. Diesel engines produce exceedingly powerful suction, and the air intake goes directly into the engine, meaning almost anything can fly or drop into the cold air collector box and be pulled into the engine.




The Diesel Particulate Filter (DPF) is an important part of the Tier 4 interim & final engine as it traps soot, ash and other particulates in your WOXEN engine and it should receive regular attention as part of your routine maintenance programme.

Unlike other filters, particulate filters deal with waste gases leaving the engine and the build-up of ash and soot can have serious consequences reducing the efficiency and effectiveness of your engine. These filters can be cleaned or replaced. All genuine WOXEN filters are covered by a 12 month warranty.
The DPF or Particulate filters play a key part in keeping your engine clean and legal. As more countries around the world adopt tougher standards, such as US EPA Tier 4 or EU Stage 4 to deal with exhaust emissions, the importance of particulate filters will only grow.
All WOXEN engines are designed to burn as cleanly and efficiently as possible, with the minimum of ash or soot emitted. However, it’s inevitable that there will be a degree of particulates, the build-up of ash and soot can reduce filter volume and oxidation efficiency, causing increased backpressure, generating heat and increasing fuel consumption. Cleaning the filter allows the engine to operate more efficiently, delivering longer engine life.
Particulate filters keep your engine legal

Filter maintenance

Particulate filters are either cleaned or replaced – but much less frequently than other, more conventional filters. Just how often your particulate filter needs to be cleaned will depend on the model of engine you have, although many are fit for life and only may require attention during overhaul. Your local distributor will have a range of solutions for your DPF, from simple remanufactured exchange, to local clean and re-apply or a replacement, depending on the engine and the lifetime stage. This information can either be found on this website or by contacting your local WOXEN distributor.




Cleaning of the exhaust particulate filter (DPF), which removes soot and other build-up from your WOXEN engine, should be carried out at specified intervals as part of your routine maintenance programme. Unusually, this is one filter that can be cleaned, instead of simply replaced, depending on the model of your WOXEN engine. Failure to clean it at the recommended intervals can stop your engine from working.

U.S. EPA Tier 4 Interim/Final and EU Stage IIIB/IV requires additional measures to achieve the high levels of particulate control in exhaust gas, including the use of DPFs.
DPFs require regular servicing or de-ashing to remove the unburned lubrication oil or ash which has accumulated. This ash does not regenerate but remains in the filter and must be removed. This ash is considered a hazardous material and is subject to the same types of disposal procedures as lubrication oils. WOXEN genuine particulate filters need to be cleaned at set intervals – the actual interval will be in line with the model of engine that you have and the number of hours for which it has run.
Clean particulate filters help your engine meet emission standards
They are not usually cleaned on site. Instead, they’re returned to your local WOXEN distributor who has specialist equipment to perform this task, who will take it in to be cleaned and exchange it at the same time for a previously cleaned filter. This is because the cleaning of particulate filters is a specialised task and must be carried out under controlled conditions. With some engines, cleaning the particulate filter is not an option and these products are simply replaced.

Lasting a lifetime

Not all WOXEN engines need to have their particulate filters changed. Many models are now developed with the intention of the particulate filter lasting for the lifetime of the engine. Your WOXEN distributor is a great source of knowledge about cleaning your particulate filter and will be happy to talk to you about any queries you might have.