Counterfeit filters: It’s all right until you take the wrappings off

A bonanza for counterfeit products. More and more dubious companies copy high-quality products of renowned brands down to the packaging – in the hope, to make easy money by illegally using good names and bad materials. As top-brands, MAHLE Filter and Knecht are not immune to counterfeiting.

Counterfeiting of automotive components is not a harmless crime but a real danger: the examples shown here are not only damaging to the reputation of the copied brands but also to the engine – and therefore to everyone in the supply chain who sells or is fitting such components. However, the counterfeits are not easily recognised – from the outside, the illegal copy is often inconspicuous. This is why our experts have looked inside of two rather impudent counterfeits.

The oil filter: The counterfeit is not operational

Tested and not passed
The filter, allegedly an OC 257, which a retailer sent to MAHLE Aftermarket for investigation, did initially not look conspicuous. After a simple scratch test at the printed label matters became more doubtful: the paint could easily be removed with the fingernail.

At the left, the original with abrasionresistant printing. At the right, the counterfeit, where the printing could be removed with the fingernail.

Missing corrugation: cause for leakage
After opening the filter, a look at the end plate: in the counterfeit the second corrugation is missing. In the original, it serves to reinforce the cover plate to prevent distortion under load which causes the sealing ring to loose its sealing ability.


		The end plate from the outside: undistinguishable.
		But internally the counterfeit lacks the reinforcement corrugation.

Filter element: short and bad
Now the actual filter element: this is 10 mm shorter than in the original. This results in about 9 % less filter surface – and therefore less filter performance and reduced dirt pick-up. Furthermore, the element has only 60 pleats instead of 80! The lower number of pleats alone leads to a reduction in filter surface by 25 %. This means that together with the 9 %, the dirt pick-up is reduced by 34 % and the service life is reduced by 34 %.

Also the irregular pleat geometry is noticeable: sections of the filter paper are folded very tightly – just short of block forming. However, in other areas the distances are much too wide. Furthermore, the adhesive bond is missing at some areas between pleat star and metal plate, with the disastrous result that oil is here flowing directly from the dirty side to the clean side!


		At the left, the original, right the counterfeit: a shorter filter element and irregular pleating.
		In detail: the pleating is inadequate – and partly not glued on properly.

Anti-drain valve: not so clever
A particularly critical part is the seal between the dirty and clean side in the area of the anti-drain valve. In filters of the brands MAHLE and Knecht, the filter element is distinguished by a clean radius that, in connection with a precision moulded rubber part, serves as a perfect anti-drain valve. However, in the counterfeit filter, a sharp metal edge can be seen and the oil is flowing directly pass its sharp, cracked edge – without filtration – from the dirty side to the clean side.


		The original: a precision seal.
		The counterfeit with sharp, leaky metal edge through which the unfiltered oil can flow.
		In the original, the anti drain valve is made with a precision moulded rubber part. At the right, however, the counterfeit with a simple, punched out rubber disk that does not fit tightly to the sealing surface. The result: depending on the fitting orientation (filter fitted horizontally or on its head), the filter can drain entirely after the engine is stopped – and it has to be filled again completely at the next start of the engine. Until this happens, the engine is not supplied with the necessary oil (pressure). In the long run, this will lead to increased wear at the different lubrication points in the engine such as crankshaft bearing, camshafts or cylinders.

Breakdown at the bypass
The bypass valve of the counterfeit oil filter concludes its disqualification. This important part has the task to ensure the oil supply of the engine under all conditions – for instance, also when an element is completely blocked or at extremely low temperatures (resulting in highly viscous oil). In the counterfeit, this valve is completely non-operative: the spring tension is so low that it stays open even under normal operation … and the oil flows permanently to the engine without filtering. This means that the copied oil filter cannot do its job – with the result that the engine will be damaged in a relatively short period of time.

		The MAHLE bypass valve
		And the non-operative counterpart in the counterfeit filter

The fuel filter copy: no filtration

Plastic instead of aluminium
The counterfeit KL 72 arrived at MAHLE Aftermarket in a rather impudent form: in old Knecht packaging that was obviously a fake. When opened, it became quickly clear that it had to be a counterfeit: while the fuel filter is normally made from aluminium, the cheap imitation was made from plastic. Furthermore, it had the wrong designation: instead of the German word “Kraftstofffilter” it read “Krarislofffilter”.

We make the KL 72 from aluminium. The counterfeiters are content with plastic – and spelling mistakes on the housing.

Not tight at all
The filter element was inconspicuous at first sight but showed a significant flaw: the sharp edge is completely unsuitable for sealing the dirty side from the clean side – a radius is required here.
Also the difference in size between the hole in the filter element and its counterpart is so large that no seal can be expected: the fuel flows unfiltered from the dirty side to the clean side.