Pollen filter

A cabin filter, also known as a pollen filter or passenger compartment filter, protects the driver and passengers against dust particles, soot, pollen, mould spores and other contaminants entering the HVAC system (Heating, Ventilation and Air Conditioning) through the air intake. In MAN and Mercedes trucks, buses and vans, this filter is a functional component of the ventilation, heating and air conditioning system. A properly functioning filter keeps the evaporator core, heater core, ventilation ducts and cabin blower cleaner for longer. This reduces odours, prevents reduced airflow and supports stable windscreen demisting. The correct cabin filter must always be determined using the vehicle chassis number. Visual comparison or selection based on the model name alone is never sufficient.

Cabin filters vary considerably depending on the vehicle series, production date, air conditioning version, air intake module and cab configuration. They are used, among others, in MAN TGL, TGM, TGA, TGS, TGX, TG3 and TGE models, as well as Lion’s City, Lion’s Coach and Intercity buses. Relevant Mercedes applications include Atego, Actros, Arocs, Axor, Econic, Sprinter, Vito, V-Class, Citaro, Intouro and Tourismo. Dimensions, sealing edges and filter media may also differ by version on Neoplan Cityliner, Tourliner, Skyliner and Starliner models.

Standard particle filters generally consist of pleated synthetic fibre media with a plastic or cardboard support frame. They primarily filter coarse and fine dust particles. Activated carbon filters additionally contain an adsorption layer that partially captures exhaust gases, ozone and odours; this version is particularly relevant for urban distribution, bus transport and vehicles frequently operating in tunnels, terminals or heavy traffic. Pay attention to the length, width, thickness, position of locating tabs and sealing lips. A poorly fitting filter allows unfiltered air to flow past the media, while an excessively thick cartridge may deform the cover or filter housing.

A saturated cabin filter usually causes limited airflow from the ventilation vents, slow demisting, increased blower noise and insufficient cooling or heating comfort. With activated carbon filters, recurring diesel or traffic odours in the cab are an important indication that the adsorption capacity has been exhausted. Damp filters may also lead to musty odours, microbial growth and condensation on the windows. In buses, these issues are often more noticeable due to the higher air volumes and longer operating times of the climate control system.

Start with a visual inspection of the filter element: check for dark contamination, leaves, traces of moisture, collapsed pleats and a detached sealing edge. Then measure the air velocity at several outlet vents using an anemometer and compare the values at the same blower setting with a vehicle fitted with a clean filter. Also check the air intake grilles and drains for leaf build-up, as a new filter will not resolve a blocked air intake. If airflow remains limited after replacement, inspect the cabin blower, controls, air flaps and evaporator for contamination. A significantly increased pressure differential across the filter housing indicates blockage, but may also result from an incorrectly fitted element or reversed airflow direction.

Replace cabin filters preventively according to the maintenance schedule, or sooner in intensive urban use, dusty working environments, agricultural applications or where there is frequent idling. Install the new element with the indicated arrow in the correct airflow direction and clean the filter housing before closing the cover. Damaged clips, seals or covers must be repaired to prevent bypass air and water ingress. Braem can use the chassis number to assist with the technical identification of the correct filter version, helping to minimise downtime caused by incorrect delivery or poor fitment.