To Clear the Air.....

[GMAs]

Dave is right... at annual you should replace them... they are cheep... but, if you fly more than regular... they can be cleaned and recoated...(the coating is a fire protectent more than a getter for dirt) its when the brown stuff starts coming off in your hands... you want to replace them... as the foam is breaking down... as to any damage... their is a screen on the inside of the filter element.. that stops rocks and small children... so the size of what gets thru might be chunkie... it would be probably the burnt rubber smell.... from the element going thu the engine... and out the exhaust... but,

Dave is correct you should replace them on a regular interval... like the element every year.... and they are cheep so its not that bad

... while your at it ... change the vacuum regulator filters too... them things that one is out on the firewall.. the other under the back deck... new is good here too.... about a buck a piece... they make them white for a reason... and if they look black... time to get one from the box... smile... GMAs