DIY: Cabin Air Filter, the INEXPENSIVE Way!
You already know that BMW Activated Charcoal Filters or Mann Cabin (non-charcoal) Filters are $30-45 per pair of Cabin Filter, which is rather expensive for this low-tech device.
This is a DIY (guaranteed easy!!!) using Standard Engine Air Filter for $6.50/each or $13 total. So you will save $15-30 easily.
1. How Activated Charcoal works:
- The activated charcoal basically filters out the odors (farms, pigs, cows, NYC exhaust etc.).
- However once the charcoal pores are filled with these odorous particles, then the charcoal component of the filter is saturated and useless, but the Air Filter still filters through pollens, dusts, particles etc.
- The lifespan of activated charcoal depends on how much smelly stuff the filter has to adsorb.
2. As an inexpensive substitute (not activated charcoal):
- Use 1998 Cadillac Deville ENGINE Air Filter as a reference for E39 CABIN Filter. So any of these Engine Filters will work:
- Fram CA6479 ---> $6.50
- Purolator A34479 ---> $6.50 (at Advanced Auto Parts).
- Microguard GA34479 ---> $6.50 (at OReilly Auto Parts).
271 mm x 203 mm x 43 mm
(Stock Size is: 267 mm x 201 mm x 30 mm)
These filters are a tiny bit bigger but all you have to do is: using a utility knife and trim 2-3 mm of rubber molding on each long side and it will fit perfect. You will save $15-30 for beers money…...hehe!
This is the shortest DIY that I ever wrote: 1 picture! Just a way to save some money during this goofy economy....
18$ for a homemade filter?
You know you can find filters for $20 and not go through all that work?
Nope, it is $13 for a pair of Filters (instead of $35-45 for a pair of Mann or OEM Filters).
It is not home-made, it is the same filter used for Cadillac Engine lol...
It is not much work at all, it takes 5 seconds to trim the rubber on each side. Max 10 seconds total and it fits right in!
good DIY and money saving tip...but I'd rather have fresh carbon filtered air. Its nice to smell leather and clean air than exhaust and cigarette smoke from other drivers.
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Sounds great! I'll do it today. Very smart. Thank you for the posting.
Kudos, thank you.
hey bro thanx a lot nice to see some ghetto mods for a change!
defintely going to autozone 2 pick up some caddy filters
hey cnn which side of the filter goes to the bottom?
slightly off topic: i graduated from creighton a few years ago! go jays!
Last edited by Young Pete; 10-01-2009 at 04:05 AM.
This is because AirFlow enters the bottom, then UPWARD through the A.F. then into the Rubber Bellow into the car.
Wire mesh is ALWAYS downstream of air flow through an air filter, whether it is car or home HVAC filter.
BTW, what program did you graduate from Creighton?
I just bought my car a few days ago and I noticed a bit weird smell... Saw this mod, did it yesterday in like 10 min with the cleaning and cutting and all and voila ... no more smell! Great cheap mod, I used the Fram parts above and cost me with tax $16.60
I tried something similar and it just didnt have the same fresh effect that the activated charcoal did...
I can't wait until someone tries this with K&Ns and lists it as a mod
Actually it's a good tip. Excellent DIY material and stuff like is what makes a forum into a community.
Let us redefine "progress" to mean that just because we CAN mod a thing, it does not necessarily follow that we MUST mod that thing.
Just got my E39. How do you know when to change the filer other than the maint. manual recommended change?
Another trick is to remove the A.F. and hold it up aginst the sun at noon, if you cannot see any light passing through, it is bad. Replace it.
You may want to google to find out what other people do to inspect their A.F. in the car or even at home HVAC system and post something here as a feedback.
Sold i am doing this
I cannot help but wonder about the fact that the Cadillac filter has about twice as many filter ribs as the OEM. How does that affect the airflow rate/necessary air pressure through the filter and the difference in drag on the blower motor?
Caddy filters are a much less expensive option until the blower motor must be replaced. Was this possibility considered and eliminated?
more filter pleats = more surface area for air to travel thru = less resistance. creighton wins?
Did this today... works Great, with better air flow...
Also, I place a Fabric softener sheet, on top... (mountain Breeze)
BTW, they were 5.60 each at Meijer's
I love the Bosch units I bought for my 02 M5... !
Wow,.. I got raped at the stealer for 80 bucks a pop on the filters...where can I get the stock filters cheaper? I looked all over before I decided on the dealer..
Or you could go here:
These are aftermarket carbon activated filters. $15 a pair (plus shipping). If you look hard you may be able to find free shipping if you order a few other things.
obligatory e39 angel eye sig photo