I put a Ford sever duty (Donaldson) air cleaner on my 03' Super Duty. I can replace it a regular intervals but when do I know it NEEDS changing? The vacuum guage on the housing doesn't seem accurate to me.
Did you put the new restriction gauge on it at the same time? I think those are fairly accurate. I'm in a very dusty environment and I put 30k on mine and was at about 3/4 restriction. I decided I'll just change mine out as part of my regular 30k maint. (flush tranny, new air filter, new ccv filter, etc.)
I look at mine regularly also and it doesn't look dirty to me. A new restriction gauge came with the new filter housing but it always showed restriction even with a new element. I was thinking that I would see a change in performance, like lower boost or something like that. I'll keep an eye on it,
With an AFE cleaning kit. The instructions on how come with the kit. Basically you spray it down with a degreaser, let it sit for 10 minutes, wash with water from the inside out, let it set for a couple of hours, then reoil it.
Don't depend on that gauge to give any indication of the air filter status(at least on the 7.3L's) but for filter replacement of the big conical Donaldson I'd replace it every 15k-20k miles but thats my preference unless you operate in very dusty environment which could accelerate the intervals.
If you filled out your sig in the user CP we could tell what kind of truck we are dealing with.
Are you chipped? Have you done the fender sleeve mod? I've read chipped trucks can pull the gauge with no mods to the airbox on the AIS. The PoweCore filter supposedly can hold like 3 lbs of dirt.
This is what's keeping me from getting the AIS, that and I like the sound of my current setup. I go around 15k on my paper Donaldson.
FWIW the restriction gauge on mine works great. It just takes a REALLY long time to get enough restriction to make it start reading. By the time I got to 3/4 restriction the obvious change was that when I stomped on it to exercise the injectors I got some serious black smoke. With a clean filter I get a puff but none of that constant black smoke like you see from the guys with the hot chips.