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From: Don Eilenberger <>
Date: Fri, 11 Oct 1996 19:51:58 -0400 (EDT)
Subject: Re: E34 microfilter

Some time back, I asked here on the list how to replace the E34 microfilter for the AC/Heating system. Charles Vickers was kind enough to do an initial FAQ on how to do it. It was VERY useful.. I've decided to pass this along to the list, with a few minor additions I'll make since about 5 minutes ago I finished doing it. It took less than 1 hour to do thanks to these directions!

>Date: Wed, 2 Oct 96 08:44:01 -0500
>To: Don Eilenberger <>
>From: Charles Vickers <>
>Subject: Re: E34 microfilter
>I was also very apprehensive about taking on the microfilter project.
>After purchasing the filter from Imparts ( they advertise in the Roundel )
>for about $30 ( I think ) I tried to acquire as much info as possible on the

Got mine from: Steve D'Gerolamo c/o The Ultimate Garage, Emerson, NJ (201-262-0412). Steve can also be reached at:

"Steve D'Gerolamo" <>

I called Steve yesterday and got the parts I'd ordered today.. the microfilter was $26.

>Several Digest members sent me valuable info, but all seemed to be only
>partial instructions. I compiled all the sources and tackled the project.
>It wasn't as bad as I had expected, but it was no cakewalk. I will be
>glad to document all the steps for you if you are interested in changing the
>The first symptom is a lack of performance by your AC fan. Mine was
>barely blowing at the high position, so I knew something was wrong.
>Here in Houston AC is a necessity of life, with temps at around 100 F in the
>Summer and humidity +90.

Yup - noticed a real lack of air coming out of any of the vents.. there was air, just not enough of it.. the car has 68k miles on it.

>As I mentioned, just let me know if you need the Cliff Notes for E34
>microfilter change and I will be glad to send you my version.

I then asked Charles for the Cliff notes.. and got (to which I'll add a few fresh in the mind comments):

>OK, Microfilter 101 will begin.
>If you notice a lack of performance from the fan motor (output and cooling
>level are greatly diminished) it is probably the microfilter ( or as you
>will come to know it - the MF ).
>I purchased my replacement filter from Imparts, Ltd ( they usually have a
>large ad in the Roundel each month). The filter looks a lot like the air
>filter for the engine, a pleated paper element rectangular in shape.
>The only special tool involved is a Torx screwdriver #15 ( I'm not positive
>on the screwdriver number - I will check in my garage tonight - if it is a
>different number I will let you know ). I bought mine at Sears for
>around $3.00.

It actually is a T-20.. at least that is the size that my Torx set had it marked. I have a set of Torx that fit into a little hex carrier - which I can use an angle driver with.. very handy for this sorta project. I didn't check, but it did look about the same size as Compaq uses for all their screws, so you computer techies will have it in hand.

>Step 1 - Removal of the glove compartment
>There are two straps which retain the glove box lid. They are held on by
>clips. The clips push straight out the open end of the clips. One
>face of the clip is closed and the other is open. Make sure you don't
>lose these clips when they come flying off. After removing the clips
>take the retaining straps off.
>The door will now swing free.
>At the bottom of the glove box compartment (underneath) are two clips (
>kind of arm levers). Pull the levers down and the compartment should
>drop down.

Piece of cake. You can see the levers easily if you lie with your head under the glove box and look at the back. The levers just snap down. As a side note - these levers also can be used to adjust the fit of the glovebox to the dash.. when you have it out it will be obvious how this is doemove and set aside.

>Step 4 - Finding out any debris left in the bottom of the air
box while you've got it open. For some reason the new filter went in easier than the old one t tape duct taping since I figure I'll own the car long enough to be doing this again. It really looks like it should be a 30,000 mile item, not 60,000 as BMW recommends.

>Step 6 - Congratulate yourself. Not only did you bond with your
>magnificient example of German engineering, but also saved yourself a bundle.

Dunno what the book price for this job is - but I'm willing to guess 1-1.5 hours. Figure you saved a minimum of $60.

When reassembling the glove box - you'll see the clamps in the rear can be adjusted relative to the box. I used this adjustment to get the top of the box even on both sides so the wood matches up.. as I got the car, it wasn't perfect. It is now.

>I hope this helps you. Let me know how it works out. Good luck.

Was a GREAT help!

I would suggest to anyone who wants to - this would make a good FAQ for a web page someplace.. feel free to add it!

If you're going to tackle this job, I'd also suggest having these directions with you in the car.. I did, and found Charles notes to be a big help and referred to them whenever I started scratching my head. Great job Charles and THANKS MUCH!

Don Eilenberger
Spring Lk Hts, NJ, USA
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