Having a clean and functioning microfilter in your BMW is extremely important as it promotes clean air circulation throughout the cabin while running your A/C or heater.  This filter should be changed during the Inspection II service or major tune-up on your BMW.  In San Diego we see many of these filters completely clogged with dust, dirt and debris.  With the wildfire season upon us in San Diego and Southern California clean air is of utmost importance.



Your microfilter is exactly the same as the filter you’ll see in any home heating or air conditioning system, except it probably doesn’t get as much attention.  The microfilter rests in front of the interior fan/blower of the vehicle and as air is pulled into the cabin, most all particles and dirt is filtered out. On virtually all BMWs built after 1999, it is very easy to change and something you can do yourself usually without the use of any tools.

Spray to eliminate musty odors

Spray to eliminate musty odors

Another danger of an old filter is that once clogged, the interior fan will have a difficult time pulling air into the car.  I have seen many cases where a customer will complain that their fan seems to be working but there is no air coming out of the vents while the A/C is on.  We’ll pull out the microfilter only to see it completely clogged with dirt, dust, bird feathers, bugs, dry cleaning stubs,  etc.  Old mircofilters can also produce a musty smell while the A/C is on.  Above the technician is spraying an anti-bacterial treatment on the new filter.

In San Diego, we can service or check your microfilter at any time.  Hopefully we will have an uneventful fire season, but if you live in an area affected by fires I strongly recommend that this filter, as well as your air filter, be changed out once things return to normal.

Stay Clean and Breathe Fresh!

Chris Keefer

Independent Motorcars

5836 Autoport Mall

San Diego CA 92121