Myth Busters: Part 2

Myth Busters: Part 2

In the second of a two-part series, Mann-Filter lifts the lid on more of the industry myths associated with filters.


“Instead of buying a new cabin filter, all you need to do is brush the old one until it is clean.”

Wrong! Consider the facts:
If you take water and brush to a cabin filter, it will look cleaner, but the tiny particles, such as pollen, fungus or mould spores cannot simply brushed away. In fact, the cleaning process may loosen them so that they enter the passenger compartment next time the ventilation system is operated. Other problems can also occur:

  • Misting of the windows (icing in winter), because residual moisture from washing the filter can enter the passenger compartment
  • Recurring misting of the windows in damp weather, because particles retained in the filter material do not allow the fresh air to pass through freely
  • Reduced cooling effect, because residual dirt particles can block the airflow from the air conditioning system into the passenger compartment
  • Pollen, dust and dirt particles can no longer be retained, because the electrostatic charge of the filter has been lost due to washing

Cabin filters from Mann-Filter separate almost 100% of particles less than 0.5 micrometers in diameter, as they are electrostatically charged and contain special multi-layered filter media. They must consist of purely synthetic materials, so that moisture can be absorbed.


“Provided that size and thread match, oil filters are interchangeable. Therefore, you do not have to go to the effort of buying a filter with the corresponding part number.”

Wrong! Consider the facts:
Even if the dimensions of a filter are right, it does not mean it is a good choice. From the outside, the black can make you feel confident about what you are buying, but only a high quality oil filter offers optimum protection. It’s what’s inside that counts:

■ The filter material must be suitable for the engine and application

■ Only the right filter that matches the application perfectly is able to retain separated dirt particles until the next change is due

■ Depending on the type of engine, a filter needs a certain number of valves for optimum protection against engine wear. Not only this, but also the correct design values, such as the opening and closing pressure of a valve

■ Thanks to the robust construction of the threaded cap, Mann-Filter filters have reliable seals and a pressure- resistant, corrosion-protected housing

We take it for granted that Mann-Filter products meet the demanding specifications of automotive manufacturers – but this is by no means always the case in the aftermarket.


“If you take a cheaper filter and replace it twice as frequently, the effect is the same as using an expensive filter.”

Wrong! Consider the facts:
Using a cheap filter in the short term doesn’t work just as well as an expensive one. Cheap filters also conceal a whole series of risks:

  • Possible leaks: e.g. at the filter medium or by-pass valve
  • Lower separation efficiency
  • Uncertainty regarding durability
  • Use of incompatible materials in the vehicle – e.g. embrittlement of cellulose media through aggressive oil constituents

Only a high quality filter really protects the engine right from the start. By using a quality filter, you can even save money and prevent costly downtime. Why should you compromise on reliability, protection and performance?


“The quicker the oil pressure light goes out again after changing the filter, the better the filter.”

Wrong! Consider the facts:
Usually, there is only one reason why the oil pressure light comes on briefly and then goes out again: when, after changing, the filter is empty for a moment. But you can confidently leave the stopwatch where it is, because the time taken says nothing at all about filter quality. The delay can be dangerous if the warning light no longer goes out – because then the oil pressure is too low. Apart from a low oil level or a defective oil
pump, the problem may also be caused by the filter if:

■ The flow resistance is too high because an incorrect or low quality filter has been used

■ The filter is full because the change interval has been exceeded

With Mann-Filter, you can be sure that your filter is not at fault if the oil pressure light comes on, because they conform to OE specifications and therefore guarantee optimum functionality at all times. Also, quality filters have an accurately functioning bypass valve, which is adapted to the engine and always opens and closes at the right time. Bypass valves used in cheap filters, however, are often badly made, or are even permanently open and therefore do not offer any comparable filtration performance. And unfortunately, no warning light will tell you that.


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