Cabin filter (pollen filter) for your car

Your Cabin filter (pollen filter) worn out? » Read more about common malfunctions • Repair • Replacement manual

Always fresh air with the interior filter

In the early 1990ies the interior filter became standard equipment in cars. This cheap and simple component represented the car industry's solution for the growing number of people with allergy. Especially tree and grass pollen cause plenty of problems for people during spring. For thirty years car are equipped with systems to prevent these allergens, making driving a better and safer experience.

Construction of an interior filter

The interior filter sits in a housing, allowing the air to flow through. It consists of a pressed and ribbed paper membrane equipped with a ring-shaped rubber. The rubber seals the filter in its housing preventing the air to bypass the filter. As it was originally intended for filtering pollen from the air, the name pollen filter is also commonly used.

Properties of a pollen filter

A pollen filter is a wear part and it is replaced on occasion of the MOT inspection. If timely replacement is neglected, the pollen filter can cause a reversed effect: bio-mass gradually builds up in the filter. Moist in the air permanently condensing on the paper membrane of the pollen filter is an excellent breeding ground for bacteria and fungi. They affect the interior filter causing large amounts of fungal spores to enter the passenger cabin. The pollen filter thus becomes a spreader of allergens. Fungal spores not only smell unpleasant and putrid, they are also the most aggressive natural pathogens of allergies and illnesses. A pollen filter replacement should therefore never be skipped. If you notice a smell, it is already too late.

Replacing a pollen filter

The replacement of an interior filter is very easy. The filter housing is accessible by way of the engine bay. Sometimes it is tightly screwed shut. Generally it is locked with a clipping system. The filter housing is opened, cleaned and the filter is replaced. It is recommended to thoroughly inspect the old filter. If it contains fungus or smells funny, the entire air duct system must be disinfected.

Disinfection of the ventilation system

For disinfection of the ventilation system the available foam cleaners are used. The procedure is simple: fill the system with foam. Wait for the foam to settle. Ultimately run the ventilation at its highest setting with the heating on until the ventilation system is fully dry. This procedure will remove most smells in the car. Should this measure in combination with an interior filter replacement and a thorough interior cleaning not suffice, there are other methods. The treatment of the interior with ozone is very effective and not really expensive.

Mind the quality

In view of the low prices of these branded articles, there is really no excuse for skipping this maintenance step. An interior filter from Bosch starts at c. 8 euro (c.£7). You won't find cheaper wear parts which are so easy to replace. The ideal moment for replacement of the interior filter is spring. This will equip your car with a reliable filter in time before the new pollen season starts. It is worthwhile looking out for special offers. The interior filters are often much cheaper outside the season. This makes the replacement of the interior filter even cheaper.