Cabin Air Filters - how often?

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How often should one change CAFs?
My BMW has 42k now on the factory CAF.
(It's one of those charcoal activated ones that filter not only air but also detects odors/pollutants, etc and switches on recirc when the climate control is on auto mode).

(I noticed that inside windows have been fogging up quite often recently...and while reading about CAFs, I noticed one article where it said that it CAN be a sign of the CAF has run its useful course ... )

Is it time? The OEM CAF (made by Corteco Micronair) is on sale right now for $28 shipped...

Wonder if I should go ahead and do it? (5 min job, looks like)
 
My kia calls for a new one every 15,000 miles, seems like a short interval but I do it anyways. I would just go by what ever your owner manual says.
 
You only really need to change it if airflow is reduced or if you are getting funny smells.

My Honda's factory filter was so cheesy and flimsy that it only lasted 2 or 3 months before it began to stink. At the dealer they want $35 for a new one, so I've never bought one. Either run without or use pieces cut out of a $4 furnace filter (which only last a month). Last month I bought a activated carbon filter for an A4 for $14 and cut it to length. So far so good but I don't expect to get more than 6 months out of it as filthy as the air is here.
 
For some reasons unknown to me the cabin air filter is usually clogged up earlier than engine air filter in all my cars. The air flow from the vents is reduced quite a bit after cabin air filter is in used for 30-35k miles, at the same mileage the engine air filter is barely dirty.

If you can remove the cabin air filter easily you should do it to inspect and tap the dirty side lightly on hard surface to remove the loose dirt, leaves, bugs ... then reinstall while waiting for the new one.
 
Thanks for all replies.

It's not that bad that I can't wait for the new one (Actually ordered one after I started this thread it as the sale is for a limited time, so it should be here soon).

I guess with 42k miles on the factory one, and as it seems most of you guys' cars call for 15-20k mile intervals, it's probably not overkill to change now.

EDIT: found out that BMW also calls for every 15k CAF changes apparently.
 
I am fairly certain that they are becoming an annual replacement on many cars.

I think it is annual on the Jag.

I will admit that i bought one for the Clio but haven't changed it yet.

Been in the garage for 2 years.

I think i will buy a new one and change it when the weather warms up

I used to change the cabin filter whenever i bought a used car from auction. Part of my post purchase catch up maintenance.
 
Originally Posted By: actionstan
My kia calls for a new one every 15,000 miles, seems like a short interval but I do it anyways. I would just go by what ever your owner manual says.


I do the same, and after seeing the condition of my Sorento's filter at about 15k miles, its probably an okay idea. Plus I was noticing weird smells, after replacing the filter air coming out the vents was nice and fresh again.
 
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I asked my friend, retired BMW Master Mechanic running his own indy shop now, and he said:
"I have seen too many people either neglect their cabin filter, or not even realize it exists, and the result is far too often that the blower motor resistor fails. One could argue correlation vs causation, but in 30+ years, I've only seen that resistor fail twice on cars that had their cabin filter changed at reasonable intervals, and I couldn't even begin to tell you how many issues I've seen from it not being touched..."
 
In my Silverado....... every spring.
I get them on good sales so no big deal. I like the clean/fresh air and
it is a 5 minute chore.
In my Son's Altima.... every two years. He see's less dirt roads.
It is amazing how nasty these things can get even after a year.

YMMV

JP
 
My S2000 is a convertible and if it isn't raining outside the top is down. So all I do is take the dirty one out, put the clean one in and then wash the old one, let it dry and put it in the next time(about every 6 months).

ROD
 
I've only used 4 in 8 years on the car in my sig, I simply look at it. it's a 30 second swap on this model so it's ultra easy.

I like the ones with the activated charcoal, really helps the sinuses...
 
Owner's manual specifies every 12 mo or 12K miles so that's what I do. As JP mentioned, I get them on sale and its just part of routine maintenance.
 
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