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Subject: Changing the under-dash microfilter and sword removal in a '92 750iL Author: DavidC (moderator) : member since December, 2003 : 11919 posts Posted on: 2005-02-14 00:01:07

Most e32's from 1991 on up have a microfilter buried deep within the dash that's designed to filter outside air before it enters the cabin. Unless you've taken the trouble to change it yourself, you're probably still on the original. If so, you can safely bet dollars to doughnuts that the filter is, well, FILTHY.

A clogged filter can make your car smell bad plus it restricts air flow, making the blower fan work harder. In this article, I'll show you how to change the microfilter without removing the glovebox, saving yourself an hour or more of labor at your friendly local dealer. A lot of dealers don't even know about the existence of the microfilter, which may explain why I've spoken to so many e32 owners with what appear to be original filters in their cars (including myself).

Tools
You'll need the following:
8mm socket
T20 torx screwdriver
Philips screwdriver
Flashlight
Vacuum

Parts
Part # 64 31 1 390 836. Here's the ETK parts diagram.


The new microfilter.


The Procedure


Start by swinging the glovebox forward all the way.


Remove the carpeted panel with a philips screwdriver.


Lie on your back beneath the glovebox and look up. Remove the two philips screws that secure the air duct.


Pop out the plastic rivet on the right that attaches a cover to the air duct.


Remove the third philips screw that holds the air duct.


Now remove the 8mm hex screw located on the left side of the glovebox, just below the wood trim, then remove the black plastic cover (the one with the "achtung" label).



Remove the air duct by reaching in and pulling it down.


Now that the air duct has been removed, you should see something like this beneath the glovebox (looking toward the center tunnel).


Disconnect the black electrical plug from the sword. Disconnect the blue and yellow plugs to get the wires out of the way.


Using a T20 torx screwdriver, remove the two screws to release the sword.


Slide the sword assembly out.


Push the wires at the top aside to locate the black knob near the upper end of the green plastic. Turn it 1/4-turn counter-clockwise as shown.


Using the T20 torx screwdriver, remove the lower screw as shown.


Pull the green plastic door away and set it aside. Your should look like the photo above. When reinstalling, be careful not to break the black knob. Here's a useful tip. When reinstalling the green plastic sword cover, you can pull the yellow/blue connectors out slightly to get the sword cover into position.



Remove the old filter, noting the position of the tab along the edge.


This is the "clean" side of the filter. You can see that a lot of dirt was getting through it.


The old and new filters, side by side. The one on the left is the side exposed to the incoming air. It was so black and crusty that it was hardly recognizable as a filter when it was in the car.


Vacuum out and clean the hole where the filter mounts before installing the new one. You'll be amazed and appalled at what you find.

For information about repairing or rebuilding the sword, see Gale's Microfilter Change page.

David Cecil, KI4GZR
'97 740iL, 127k miles
'92 750iL, 77k miles
'86 735i, 95k miles

www.e38.org has links for everything about your BMW 7-series automobile

• Changing the under-dash microfilter and sword removal in a '92 750iL (pic) (url) - DavidC 2005-02-14 00:01:07 (21588 views)
  • Re: Changing the under-dash microfilter and sword removal in a '92 750iL - 93740il 2005-02-14 08:39:50 (1258 views)
    • here is the truth who actually did it, hehe (pic) - shogun 2005-02-16 01:37:26 (1750 views)
      • You got me! She's a champ, for sure! (nt) - DavidC 2005-02-16 01:58:10 (939 views)