How Frequently Should The Microfilter Be Changed

[Disneygrad]

Changing one is no problem, it is clearly listed here. Does anyone know
SPECIFICALLY what the change interval is i.e. in miles and/or months?

[chefwong]

It's a personal preference IMO...
I tend to change mine every spring. It's a small pricepoint but NYC air ain't the cleanerst.

[JCL]

It is called for in Inspection I, which is usually at 30,000 miles.

Every year seems a little early. If I was in a NYC, I might go every two years. As chefwong says, anything earlier than scheduled is personal preference.

[rayxi]

It's easy enought to have a look at it whenever you get an oil change. If it's black or obviously clogged with build up then change it. Otherwise go with the 30k interval.

[Disneygrad]

Thanks, crew, for the various replies. Thirty thousand (30,000) miles being mentioned, I seem to recall that my wife's S2000 is set at the same replacement recommendation interval. Additionally, the "common sense" (something sorely lacking in many quarters these days) suggestions about environment I sort of figured out myself. The "checking it" is a little much for an old-timer like me UNLESS I am routing around in the engine compartment for more serious issues...but again, thanks for the suggestion.

Disney

[X5 Meister]

I'd check it sooner then that for a bunch of reasons:
1. Debris accumulates around the filter (in the housing) such as leaves, dirt, etc. You should vacuum that out.
2. If you notice a stale or musty odor from your A/C system, removing the microfilter and spraying some A/C cleaner in there while the system is running will help kill the mold that causes that smell.
3. It is my understanding that an engine oil service includes a microfilter change (though not the annual oil change per se) as well as the Inspection I and II. Given that since 1999 BMW has officially extended the oil change interval to around 15,000 miles, seems like the microfilter should be changed about ... every 15,000 miles!
4. If you want to keep the inside of your car as clean as possible change it more often, that will help keep the dust level down.
5. My last microfilter change interval was 25,000 miles and the filter was incredibly filthy. I'm going to do 15,000 miles max for next time.
6. At the very least remove it and hit it against the curb or something to shake out as much dirt/dust as you can. Make sure not to reinstall it in reverse though!
7. BMW makes 2 types of filters (a standard one (shown on the left below) and a carbon one (shown on the right below)), make sure to get the carbon one which also removes some odors.
8. It's relatively cheap $30-$40.

[jquang]

i know there is one filter underneath the wipers, does anyone know where the second filter is located. thanks.

[X5 Meister]

That's the only one. What I meant to say was that BMW makes 2 KINDS of filters.

[jquang]

thanks for the prompt response mgruber. is there a difference between the microfilter and air filter? thanks

[X5 Meister]

air filter is for the engine. microfilter is for the cabin.