I have the K&N factory replacement filter - not sure if it's related to that...

The foam that runs around the outside of the filter holder has sort of crumbled a little and has gotten sucked into the air filter. I was wondering how that would be able to happen, thinking the filter box SHOULD be sealed off from the outside...so I guess that means there's at least a gap there near the bottom. Since the bottom of the air filter is the side exposed to the outside world via the beather tube...that's the side that has the foam bits sucked into it. Anyone else notice this with either the factory filter or the K&N replacement? I have 30k miles on it now (5.4L).

 

My recall is a trifle foggy as to the source (the manual?), but I believe there is a Ford recommendation that any replacement filter is to have a FELT gasket as does the OEM.

When I replaced the OEM with a K&N drop-in, I wondered about the rationale for K&N's foam construction.

 

Maybe you saw that in the owners manual. I swear I remember reading that somewhere too. I think I'll switch back to a stock filter this summer. I don't like the thought of crap getting sucked in right there at the filter instead of out at the end of the tube where the air should be coming in.

 

I opened my airbox and looked at the filter this weekend. There was a sticker in or on the airbox warning about the FELT gasket. First time I ever heard/read that.

(Not sure about the manual. I haven't read mine lately though)

 

Oh ok. I think that's where I saw it then.

 

I had to go anyway, so while at Adavance Auto Parts I grabbed a new Purolator air filter that's a good match to the factory filter. It was $16.96 and has the felt. Part number A35528. This is for the 5.4L. Now I don't have to worry about it. Just need to figure out if I wanna stick that K&N out on ebay or not. Might not be worth the trouble to ship for the small $ I'd get.