Filters

Delving inside the depths of filtration

With filters being one of the aftermarket's most popular service parts, it is worth appreciating the less obvious facts surrounding them, as Rob Marshall discovers

Even though purse strings are tightening as costs rise, garages should not scrimp on filtration quality. While not all the companies that assisted us with behind-the-scenes information supply the vehicle manufacturers, they all produce OE quality filters. While an incorrect filter can increase wear, reduce performance and raise fuel consumption, a technician cannot be expected to spend valuable time identifying a poor quality filter from one that meets (or exceeds) vehicle manufacturer specifications.

One major issue is that deciphering filter quality, with a cursory visual inspection alone, is almost impossible. Therefore, within a workshop context, quality is taken as a given – a conscientious technician is more concerned with fitting the part correctly. Mahle confirms that filter medium materials, dimensions and, where fitted, pressure valves, are all developed and required by the specific engine application. This means that sacrificing any one of these parameters is going to create problems.

It is all too easy not to appreciate the considerable efforts that go on behind closed doors at quality filter manufacturers but keeping abreast will benefit aftermarket garages

WHY LOW-GRADE FILTERS DO NOT MAKE SENSE

While not obvious, using a poor-quality oil filter can be ruinous. Small abrasive particles that are permitted to circulate around the engine will destroy the working surfaces rapidly, including cylinder bores, bearing shells and the turbocharger shaft. While Comline agrees that a poor quality oil filter can cause terminal engine damage, the filter is not always to blame and technicians should rule out underlying engine problems, especially if an OE quality filter has been used. A sticky oil pressure relief valve, or even oil pump failure can be misdiagnosed as a filter issue, for instance. Borg & Beck highlights that a low-quality air filter can cause a fluctuation in the airflow meter, leading to an imperfect fuel to the air mixture. The consequences of this include a loss of power, higher fuel consumption and non-uniform engine operation. While a poor-quality fuel filter can allow contamination, such as metallic particles and dust to enter and damage the delicate fuel injection components, UFI (like Comline) has found that substandard, or even counterfeit, filters can employ cheaper pleated paper mediums, which struggle to separate moisture from the diesel fuel, if at all. The company explains that this is why it employs more advanced materials that are resistant to so-called biodiesels – an important consideration, as UK pump fuel contains up to 7% renewable content.

UFI reports that it supplies Stellantis with the OEM diesel filter for Alfa Romeo's Tonale. The company's Gen2 Plus filter utilises the company's FormulaUFI.StratiFlex technology, which filters more than 90% of particles up to 4 μm and has a 95% water separation capability. While the Tonale was launched earlier this year, the filter is available already in the UFI Aftermarket Catalogue.

Yet, Comline confirms that low-quality filters are circulating within the marketplace and we should be aware of them. Inferior materials are a common compromise on such parts, which may not perform the job with which they are tasked. Comline highlights seals, for instance, where different rubber compounds are used to cut costs, despite the design appearing to be the same. Comline also attests that several different grades of filter medium are employed and the use of a lower-cost one in an inappropriate application could well reduce cost but at the price of quality.

"It is all too easy not to appreciate the considerable efforts that go on behind closed doors at quality filter manufacturers but keeping abreast will benefit aftermarket garages"

DELVING FURTHER BEHIND THE SCENES

While two identical filters may look the same from the outside, their performance can deviate wildly. To show just how stark the differences can be, UFI has sectioned one of its OE diesel filters (below left) against a counterfeit example (below right), both of which are applicable for the same PSA/FCA/Stellantis range of diesel vehicles.

The most obvious difference is that the sub-standard part lacks a central pillar, placing the unsupported filtration medium at risk of collapse. Additionally, the filter base lacks a support spring, adding to its instability. UFI also reports that the non-composite filter material creates debris, which can break off and end up contaminating the fuel that enters the engine. As the filter material composition is unknown, this calls into question not just its ability to filter fine particulates but also the capability to separate water from the fuel. Even if it could perform this vital task satisfactorily, the water presence sensor housing is not magnetised, which means that the car cannot detect when the water level within the filter reaches a critical level and warn the driver.

"Do not forget the upselling possibilities with cabin filters. Borg & Beck highlights that a standard cabin filter can be upsold to active carbon, or biofunctional types"

Above and beyond

Again, quality filtration suppliers are making advances that may not be that obvious. Comline, for instance, has just modified the design of its EFF235 and EFF246 diesel fuel filters, used in a variety of brands that employ the popular Ford/PSA/ Stellantis 1.4, 1.6 and later 1.5-litre engines. Comline reports that this part's original design promoted leaks, a common and, understandably, serious problem. This led its engineers and manufacturing teams to redesign the filter to address the issue.

As all quality manufacturers emphasise the importance of the filtration material, we should not forget the considerable R&D that goes on behind the scenes. FormulaUFI.STRATIFLEX is one of the latest examples of this, which comprises a combination of various materials, including cellulose, glass fibre and hydrophobic fabrics. The company uses these combinations in its diesel, air and oil filter ranges.

Do not forget the upselling possibilities with cabin filters. Borg and Beck highlights that a standard cabin filter can be upsold to active carbon, or bio-functional types. The brand's parent company, First Line, provides free posters to help communicate the importance of cabin filter replacement. These can be ordered via www.firstlineltd. com/posters. Note the use of pre-filters on these new and old OE quality air filters

SUPPLIER CONSIDERATIONS

How can you be sure that the filter you fit to your customer vehicles meets OE quality? The reassurance of a brand helps but a big part of this is your supplier. Can you trust your parts provider to ensure that the filter within the box meets your expectations? This is a crucial consideration. Should you be asked to install customer-supplied parts, be wary that online marketplaces are awash with counterfeit and lowstandard components, for which you may have to bear the consequences. Mahle adds that copy parts are a false economy, because car owners should consider not just the cost of consequential remedial work but also the inconvenience of losing access to the vehicle, while it is being repaired. When discussing the humble air filter, Borg & Beck highlights the importance of the seal as critical for the entire filtration process. This is because it must provide the perfect connection between the filter and housing, as well as not deteriorating for many thousands of miles. The company also highlights that many low-quality filter manufacturers do not include the pre-filter that is necessary for a dusty environment, which a technician can spot fairly easily. Borg and Beck also warns technicians not to clean the air filter with an airline, instead of replacing it. While the air stream will remove larger particles, it will penetrate the smaller contaminations deeper into the filtration medium.

UFI is working hard to fight the counterfeiters but it needs your help. The company is encouraging garages to be wary of suspiciously low prices and to notify UFI (through its sales network) if you come across any potentially counterfeit goods. UFI reports to AT readers that it offers immediate technical and legal support to its aftermarket distribution. Yet, to avoid any risk, the company implores that any UFI or SOFIMA filters are purchased through its official distributors.