I have a 2005 Honda Pilot EX and I want to know if replacing the engine air filter is necessary. I'm asking this because when I searched Youtube for a tutorial I could find only 1 for a 2004 Honda Pilot, which will work because it's the same car with different branding (no facelifts, nothing). I just wannt to make sure I should do this.
Air filters should be replaced when they are dirty, it's only a waste of money to do so sooner. Depending on the air quality where you drive, it could be yearly, but usually longer (3 to 5 years for most people).
I do have "lifetime" K&N air filters in 2 of my cars, it doesn't really save you gas, maybe gives you 2 extra HP, and you do not rinse these yearly, only when they get "gunky."
Disposable air filters like the one you most likely have in your Pilot usually cost about $12, whereas the "lifetime" air filters usualy cost around $65, and the cleaning kit for them costs around $15 and is good for 3 or 4 cleans, which, depending of the air quality of where you drive, should be cleaned every 3 to 5 years (in my experience).
Yes it's critical to do and hopefully has been done since 05"! An internal combustion engine breathes like we do so if you cut off it's air flow it'll suffocate. Will start getting very poor gas mileage and have huge power decreases. Replace immediately and do so each year at least. Or I'd recommend getting a lifetime K&N air filter that you rinse out each year. It cost a little bit more but pays for itself within the first ten tanks of gas in most cases because of the significantly increased amount of ait it allows into the engine.