2021 BMW 740i Cabin Air Filter Replacement Cost

Typically made of paper or foam suspended in a plastic frame, the air filter media catches the dirt and debris that comes in through the heating and ventilation air intake. Some high end vehicle have carbon activated filters that help eliminate fumes and odors from incoming air.

Deceased airflow from the climate control system may be noted with a clogged cabin air filter. There may also be a musty or moldy odor emanating from the vents as moisture becomes trapped in the system housing and ducting.

A vehicle can be driven with a dirty cabin filter. However, decreased climate control performance, or unpleasant odors may be noted if the replacement interval is ignored for too long. If left for too long, the bacteria that remains even after the filter is replaced will continue to leave a noticeable smell.

Replacement intervals vary greatly by vehicle and driving conditions. Manufacturers often recommend that the cabin air filter is replaced in alternation with the engine air filter. We see this performed approximately every 40,000 miles.

A visual inspection of the filter will be sufficient. The technician will access it by removing plastic cowling in the engine bay, or through access panels underneath the dashboard, and removing the filter. The climate control housing will be inspected for road debris, and the filter will be assessed for cleanliness.

The procedure is the same as the inspection. The technician will assess the climate control filter housing and remove the cabin air filter. Typically the filter is a cartridge that can simply be swapped for a new one. Some high end cars may have two filters that need to be changed at the same time.

Most cabin air filters are very low cost, when going through the trouble to inspect them, they should be replaced unless they have been recently serviced. Often times, accessing the filter will require removal of trim pieces with special fasteners. Trim panel removal tools are extremely helpful in this case, aiding in removal and protecting against breaking special trim clips or interior panels.

In the cases where the cabin air filter housing is accessed through the engine bay, care should be taken to remove debris (sticks, leaves, other refuse) from around the filter area before removing it. Any debris that falls in or that has gotten past the filter should be removed. Debris that gets behind the cabin air filter can clog and damage heater cores and air conditioning evaporators. Often times, these problems are difficult to diagnose after the fact and can lead to large repair bills.

Some cabin air filters are extremely easy to replace. But before ordering parts or attempting this service yourself, it is important to look for the correct procedures to replace the cabin air filter on your specific car. Certain models will require partial disassembly of the dash or lower windshield cowling in order to access the cabin air filter housing.