How dirty is your air filter?

[coopns]

I often see/read about recommendations for changing your air filter. Mine never seem dirty. I mean there is a tiny bit of dirt but nothing that bad, filter still realitely white, not a lot of debris.

Any thoughts on this? Or am I missing the boat, should it be spotless?

 

[bodeh6]

I changed mine about a month or so ago. It wasn't "dirty". It was slightly discolored, some small pieces of debris, and thats it. I have seen peoples air filters that are brown or black in color and wonder how they get like that. Mine are never too bad.

 

[The_Jeff]

Not bad now since I discovered the mice last week eating holes in it and leaving all kinds of cool stuff on the dirty side!

 

[ARCOgraphite]

At the very least, change it every 20K or couple years. It will not affect gas mileage - only power on a modern lambda FI gasoline engine. If your drive on dusty roads often youll have to change it more frequently. I have "proof" on the fuel mileage impact - I had assumed the Subaru dealer changed the wifes AF at 30k - in fact when i was doing 44k OCI service, i removed it and it was the most dirty thing i ever saw - but the car was getting its best mileage at over 31mpg average on a forester AWD 5mt. The mileage dropped to 28 after i put a new fram filter in - but man O' man did it pick up passing power! Felt like a 30HP gain!

 

[Chris142]

Mine is plugged up and causing excess Silicone in my used oil analysis and low power by 10,000 miles.

 

[Dave Hess]

Every 40K miles for my cars, but thats most highway miles.

 

[fdcg27]

Well, I just replaced the air filters in the '99 Accord and the Forester.
Both had around 30K.
Neither looked really bad.
The way in which the cars are operated, as well as the areas, apparently aren't all that dusty.
The replacement Purolators were almost free after rebate.

 

[ahoier]

I "check" mine every 12k, but most don't need to be replaced (as FRAM suggests, as their "12000 mile tune up" lol).

Generally, they last me a good 20k.

 

[oldmaninsc]

Originally Posted By: ARCOgraphite
At the very least, change it every 20K or couple years. It will not affect gas mileage - only power on a modern lambda FI gasoline engine. If your drive on dusty roads often youll have to change it more frequently. I have "proof" on the fuel mileage impact - I had assumed the Subaru dealer changed the wifes AF at 30k - in fact when i was doing 44k OCI service, i removed it and it was the most dirty thing i ever saw - but the car was getting its best mileage at over 31mpg average on a forester AWD 5mt. The mileage dropped to 28 after i put a new fram filter in - but man O' man did it pick up passing power! Felt like a 30HP gain!


100 percent agree. I've noticed on the Mercury at about the 1 year mark I feel a little loss of power at full or close to full throttle.
One year for me is about 15k-25K miles, and I do drive in the desert quit often where it is very windy and dusty.

 

[HTSS_TR]

In my area the air filters are not needed to be changed until more than 30k miles, even at that mileage it was barely dirty, when I taped the dirty side on the ground less than 1-2 grams of dirt/sand got out of the filter. I think it could be in service for another 10-20k miles. No different in power or gas mileage was detected after new air filter was in.

 

[ARCOgraphite]

Originally Posted By: Chris142
Mine is plugged up and causing excess Silicone in my used oil analysis and low power by 10,000 miles.
Dirty filters usually filter better (until the rubber gasketing deteriorates) so I would not be so sure the filter was your high Si issue - recall Si is a component of most piston alloys and is part and parcel of piston wear. I do NOT recommend checking a filter - if you open the airbox - change it! Opening and cleaning the airbox subjects the engine to the sure possibility or large grain Si ingestion.

 

[hattaresguy]

Last time I changed the one in my truck at 15k miles it was almost perfectly clean. I think this one I'm just going to ignore and see how far it goes, bet I get 100k out of it.

 

[George7941]

I second the recommendation to leave the airbox alone until it is time to change the filter.

On HD trucks, the Owners' Manual specifically instructs you to not open air filter housings unnecessarily until the restriction gauge indicates filter replacement. This is to prevent dirt from falling in when the housing is opened up.

Here is a photo of my air filter housing

I added on the Fram restriction gauge. The element now has 67k km(41k mi)/4 years on it and the gauge still indicates zero restriction. I expect the element to go at least 80k mi before I need to change it. My driving is 90% city.

Save money and stop doing unnecessary filter element changes. Leave it alone. A filter could look dirty on its surface and still be perfectly serviceable. A restriction gauge is the only way to find out if replacement is needed.

 

[mechtech2]

Baloney about the restriction gauge.
It tells about idle .
Unless you have a diesel, the you are not at full throttle - so it's meaningless. And it would have to be specifically metered for you system and location on the system.

Dirty filters are not as harmful to fuel economy as when we had carburetors - but they still have an impact on economy and power, for sure.

 

[George7941]

Mechtech2, I have noticed from your posts that you have an enormous amount of experience in the automotive field and I do find your posts to be very informative. I expect that you are a professional in the field. You moniker hints at that.

However I think you have zero experince with restriction gauges, probably because you have not worked on HD trucks. Restriction gauges are MAX reading i.e. they record the max vacuum they have been subjected to. The flag will normally only move one way and they will not move back when the vacuum disappears. The flag has to be manually reset. My friend's 05 Silverado 6.0 gas teuck came with a factory installed restriction gauge.

As far as being calibrated to the system, it is not really necessary unless you are trying to get the last bit of life from the element. You can be conservative and change the element at 8 inches of vacuum, which is early. My gauge has yet to move with 41k mi on the element.

Dirty elements have zero effect on fuel economy. BADLY restricted elements will affect WOT power.

 

[ARB1977]

I'm waiting till 40K to clean the AFE Pro Dry in the Jetta. So far performance hasn't changed.

 

[mechtech2]

Of course I have experience with those little gauges - they are common.
And even on vehicles that
have them standard, they can show faults with new air cleaners, or show NO faults with filthy ones.

 

[dailydriver]

Originally Posted By: ARB1977
I'm waiting till 40K to clean the AFE Pro Dry in the Jetta. So far performance hasn't changed.


I have this same brand filter on my Z28 now.

I switch between the AFE Pro Dry in the spring/summer, and an Amsoil EaO83 in the fall/winter.
Each one gets cleaned and vacumed once a year, and BOTH should last a LONG time on this schedule.

 

[teambeechstreet]

My mother's 2001 Tahoe went about 100K and 9 years on the factory air filter. It was still fairly clean and not much dust came off when I tapped it on the ground. Only reason I changed it out was because a local parts place gave me a free filter for it.

 

[Falcon_LS]

With all the fine dust particles and sandstorms every day, I replace mine every oil change. Can I go more than 6,250 miles on an air filter? Sure, but at $6.90 for a Motorcraft FA-1032, I don't see the point.

Same goes for my Montero, albeit Mitsu charges $25.93 for their filter. But considering the truck does about 780 miles a month, $25.93 isn't so bad every 8 months.