[crazyguy]

i always keep the air circulation mode on (not the auto mode but shut off the air coming in from outside),do i still need to replace cabin filter? or it is a wear and tear item that i have to replace regularly regardless if i use it or not ?
thanks so much

 

[cn90]

Never good idea to recirc air all the time, recirc only when going behind diesel truck with smoke etc.
Otherwise, do not recirc.
You are correct that air flows through the Cabin Filter only when in Fresh mode.

If cost is an issue, then you have an alternative using Cadillac Engine Filter for $7/each:

http://www.bimmerfest.com/forums/showthread.php?t=400819

 

[crazyguy]

thanks dude