Rain X
by Howard Smithson
First Coast Banner May/June 1997
First Coast Chapter
I've been asked several time to answer tech questions about BMWs from fellow CCA members. Since I am the service manager at Tom Bush BMW, I hope I have enough technical expertise at my disposal to answer most of your question. If you have a question that you would like answered please send your inquiry to First Coast Chapter, P.O. Box 600038, Jacksonville Fla, 32260 attention: Hey Howard, I will be choosing one or two question to answer in each newsletter. If your question is more urgent please feel free to give me a call at Tom Bush BMW.
This months question is usually asked out of frustration. What does this microfilter thing do and where is it in my car? The microfilter thing is an electrostatically charged filter that captures dust and pollen particles (down to 5 microns) that normally are drawn into the passenger compartment through the ventilation system. It is similar to the filter that you have in your home AC unit. Just like your house filter your BMW's microfilter should be changed also. The recommended interval is at every inspection #1 and #2. However, if your AC smells musty or you have decreased blower fan volume change it sooner.
As for "where is it in my car?" this depends on the year and model. The filter has been installed since 1991 in some 7 series and since 1992 in all cars except Z-3. The locations are as follows:
I hope this alleviates some of the tension and frustrations caused by the microfilter thingy. Remember send your questions for my next column to First Coast Chapter P.O. Box. I look forward to hearing from you.