Can I retrofit the cabin air filter?

[Dan in NZ]

My car came before the cabin air filter, does anyone know If one will just fit in, or is the housing completely different? I drive on a lot of dusty roads in the summer, and it would be great not to have a car full of dust.

[winfred]

i am not sure about euro cars, i did a 91 525 evap job that didn't have a filter but it did have the hole and cover for it, at which point i just stuck one in, if it doesn't have the place for it (some e32s don't, not sure about real early e34s) your screwed, the easy way to keep most dust out would be to keep the recirculate on and just don't let it in

[Mr Project]

Yeah, I looked at this on my '91, build date of 9/90, that does not have a microfilter. I had the evaporator out, working on the A/C, so I had a good look in there. There is NO WAY that microfilter would fit, and in order to retrofit it, you would need at least the whole back half of that assembly that makes up the 'box' that feeds air to the evaporator/heater core. A retrofit would be VERY difficult, if even possible. I'm pretty sure you'd have to tear the whole dash down, pull the HVAC airbox assembly, and start swapping parts in from a microfilter-equipped car.

Alternately, you could try putting a pice of thin filter material in front of the evaporator, but you'd have to pull the evap to change that every time. Or, you could try to set up filters on the air intakes in the cowl, but that's pretty tight down in there.

Just my observations from under the dash.... never tried or examined all the possibilities.

[Dan in NZ]

So on a RHD drive car, I would imagine the air filter is up near the pedals. When I'm at home in 10 days I'll take off the carpeted bump and have a look. do you think I'll be able to see the cover (if it's there) just by removing the carpet bump?

[Mr Project]

Yeah, maybe the carpet and the inner plastic liner, I can't remember how far down that plastic cover goes. Might obscure your view. You should be able to tell where the evaporator housing is, just look on the front side of that housing. If there's room between the evap. housing and the 'sword' or the 'sword equivalent' for a 1.5" filter inside that ducting, than you are probably golden.

In my case it was painfully obvious that you could not fit a filter of any thickness inside the evap. housing ducting.

[Geoff Hoad]

This is also true for the European version like we have. The whole assembly was modified to fit the microfilter in. Those hardy souls who have become contortionists when changing their microfilters know exactly what I mean. No sane man would try it.

[Julius]

This is an absolute nightmare. Im stuck atm, i got the card out of the way and the sword. This is a job for super super midget hands person.

[Geoff Hoad]

Sure is Julius. Not a nice job at all. The good news is that by the second or third time it actually becomes easier... What am I saying!!!

As for the smell, check the archives as I remember this issue being addressed before.

Cheers,

[Geoff Hoad]

To get to a RHD microfilter you need a convertional phillips head screwdriver and a #10 Torx screwdriver (optional). Undo the cover that sits abouve the pedals, then undo the carpet cover to the left of the pedals. Squeeze your head and one hand in to see a vertical yellow coloured slot. Undo the screw, pull out. Remove the microfilter. Be appalled at the amount of dirt in it. Throw away and replace with a new unit. Reverse the process. Drink beer, lots of it. After this job you deserved it.