Air filter replacement intervals - seriously, what is REALLY necessary?
 

The 06 C350 I've got now is on the original filters (yes,2, one on each side). It has been on the road for close to 3 years. They're a little dark, but the car has 28k miles and the manual calls for every 60k or 5 years if I am not mistaken. Now, on my 202, I was replacing them every 10k; they were cheap online, and clean filters are good, right?

I just feel like it's probably not necessary. When are these OEM filters truly in need of replacement?

Unless you live in a particularly dusty environment, such as dirt, sand or the occasional wild fire ash, then no one will fault you for following MB's service interval. Going longer than the service interval is more likely an exercise in false economy. Literally, how much will you be saving relative to the risk of various sensors and intake pieces?

yeah.

Wonder what MBDoc thinks

Opinion only:

How long a filter is efficient is determined by how much dirt/dust it has filtered ..years and miles mean nothing as far as I am concerned...
and any system that uses Electonic Airflow Sensing is looking for the cleanest air you can find in order to remain accurate....so, at 5 bucks a gallon, I prefer to change AF more often that not. And I clean them in between changes , along with the box they sit in..........
Overkill ????...I doubt it. You show me a dirty MAF and I will show you a dirty a/f......

Yeah, that's what I have done in the past; get the needle-attachment for the vacuum and get the big debris out of the pleats and the intake tubing, and then change em about every 6mos/10k or so. Guess it's the proper plan.

True. Every type of equipment in the world has its usage measured in terms of hours except for one: cars. The reason is because cars have odometers and not hour meters. Some people put hour meters in for this reason. I have thought about putting a "pre filter" in the tube to the air filter box to keep the rif-raf out. A lot of dirt piles up in there.

I change them once a year, air filters are cheap, gas ain't. Its also a good chance to vacuum out the airbox and wipe it down with a damp rag to get rid of all the dust and dirt.

Ditto, to both scouring the box and piping, and to having thought of doing a pre-filter for bugs and leaves

Guys, I was following some air filter threads over on the Corvette Forum; thought you might find some of the discussion interesting.

One of the guys there made a pretty good case for a reasonably dirty filter not really hurting gas mileage (under normal light-throttle driving conditions).
Seems the pressure drop behind the mostly closed throttle valve is MUCH greater than the pressure drop thru the filter, so no energy wasted getting
the air thru the filter at normal 1/8 to 1/4 throttle openings; even a dirty filter can easily flow enough air to cruise on. And today's engines adjust the fuel mixture to compensate for any slight pressure drop at the filter. Of course, full throttle is another story, and reason enough for Vette guys to change filters often.

Another thread had a big scientific test of a bunch of filter types, including the famous K&N. Bottom line was that the K&N cleaned 97%-plus of the particulates (size I can't remember) but the AC paper filter cleaned 99-plus.
The K&N allowed 17 times as many particulates to pass through; but of course had less restriction to flow at full throttle.

So, I will still change my paper MB filter at 10-15K miles, even though it still looks pretty good. even 1/10 MPG improvement pays for a filter pretty quick.

DG

Those K&N work wonders on Benz MAF sensors.....specially the Hot Film Mass ones...

I just use compressed shop air to clean out my AF (Blow inside out). My operating environment isnt all that dusty, however I keep mine clean for good measure.